Blogger Digest

Linux Command To Check System Profile

2006-10-17T13:44:00.002+08:00

Linux system administrator and experienced users might interested in getting a Linux server profile in order to understand how the Linux system being setup, what is the server hardware specification, what are the software packages or drivers being installed, does it need to be patched or upgraded, etc.

less /etc/sysconfig/hwconf to get installed hardware information.
less /proc/cpuinfo to get installed CPUs specification.
less /var/log/dmesg or dmesg to get the Linux boot up information.
less /proc/interrupts to list the IRQ used by system devices.
less /proc/ioports to list I/O ports used by system.
less /proc/dma to list DMA channels and device used by system.
less /proc/version or uname -a or less /etc/redhat-release or lsb_release -a to show the Linux version.
kudzu -p to show the probe information about hardware detected
/usr/bin/lsdev to list devices and information on system hardware.
/sbin/lspci to list detected PCI devices.
/sbin/lsmod to list loadable modules.
/sbin/lsraid to list raid device.
/sbin/lsusb to list USB device.
/sbin/usbmodules to list kernel driver modules available for USB devices.

Related information:

Search more related info with Google Search engine built-in

Using find Command By Examples

2006-10-17T08:03:00.001+08:00

The find command is a Linux command that is used to search for files in the Linux file system. In fact, it is a standard shell command that exists in most Linux/Unix variants.

Using find command by examples

To search for all files that end with .sh, from the root directory down to all sub directories. Execute the find command as

find / -name "*.sh" -print
To search for all files that end with .sh, from both the dir1 and dir2 directories, and change the file permission mode to 755 for those matching files. Execute the find command as

find dir1 dir2 -name "*.sh" -exec chmod 755 {} \;
To search for all files that contains case-sensitive search term ABC, from the root directory down to all sub directories. Execute the find command as

find / -name "*" -exec grep -H "ABC" {} \;

To narrow down the scope of file searching as well as speed up the searching efficiency, rewrite the find command as

find / -type f -name "*" -exec grep -H "ABC" {} \;

to get find command search for regular file only instead of all file type that exists in the file system.
Using the grep command by understanding grep command option switches

grep -HIirls ABC *
1. to search all files from the current directory that contain the search pattern ABC
2. -H to print out filename
3. -I to ignore binary file
4. -i to search case-insensitive
5. -r to search recursively from the directory to all sub directories
6. -l to show file name once only for the file that containing the search pattern and exit from further search when the first match of pattern found in the file
7. -s to suppress any errors message about non-existent or unreadable file
Others forms of Linux command that serve the same purpose could be

find / -type f -print | xargs grep -H "ABC" /dev/null
or
egrep -r "ABC" *
To search for all files that are 1000KB (1MB) in file size, from the root directory down to all sub directories. Execute the find command as

find / -size 1000k -print
To search for all files that are greater than 1MB in file size, from the root directory down to all sub directories. Execute the find command as

find / -size +1000k -print
To search for all files that are between 1MB and 2MB (inclusive) in file size, from the root directory down to all sub directories. Execute the find command as

find / -size +1000k -size -2000k -print

Note! Use the +/- sign to indicate range, which apply to the time related quantity, as showing below.
To search for all files that are own by user ID 501, from the root directory down to all sub directories. Execute the find command as

find / -user 501 -print
To search for all files that are created less than five minutes ago, from the root directory down to all sub directories. Execute the find command as

find / -cmin -5 -print

This form of find command is useful to find out the effects of system change after installing or updating Linux package.
Linux file creation time vs Linux file modification time

The Linux file creation refers to a file being created in the file system, changes of file permission, or changes of file ownership.

Linux file modification time refers to a file last editing time.

Take a look on the diagram below, which is a snapshot of $HOME/bin directory contents listing.

The ls -la command shows that wdf file modification or last edited time on Sep 29 11:25. Then ls -lc command shows that wdf file creation time on Oct 15 12:26 which is the time the file being extracted from a tarball.
To search for all files that are created less than 2 x 24 hours ago, from the root directory down to all sub directories. Execute the find command as

find / -ctime -2 -print
To search for all files that are modified less than five minutes ago, from the root directory down to all sub directories. Execute the find command as

find / -mmin -5 -print
To search for all files that are modified less than 2 x 24 hours ago, from the root directory down to all sub directories. Execute the find command as

find / -mtime -2 -print
To search for all files that are accessed (such as execute the file, view the file using vi, cat, less, etc) less than five minutes ago, from the root directory down to all sub directories. Execute the find command as

find / -amin -5 -print
To search for all files that are accessed less than 2 x 24 hours ago, from the root directory down to all sub directories. Execute the find command as

find / -atime -2 -print
To search for all files that are own by group ID 22, from the root directory down to all sub directories, and change the group ID to 112 for those matching files. Execute the find command as

find / -group 22 -exec chown :112 {} \;
To search for all directories that are global writable, from the root directory down to all sub directories. Execute the find command as

find / -perm -0002 -type d -print
To search for all files that are not own by any user and group, from the root directory down to all sub directories. Execute the find command as

find / -nouser -o -nogroup -print
To search for all directories exists in the file system. Execute the find command as

find / -type d -print

The alternative form of commands are

ls -ap | grep /
find / -type d -printf "%P\n" apply -printf switch to show directories name only and discarding the leading path.
To find the total disk space take up by all tarballs ended with .gz file extension

find / -type f -name "*.gz" -exec du -k {} \; | awk '{sum+=$1} END {print sum"KB"}'
To create CPIO archive backup of dir1 and dir2 directories. Execute the find command as

find /f1 /f2 -depth -print | cpio -ocvB -O /f2f2.cpio

Related information:

Linux archiving and compression command by example
Using ls command by example
Search more related info with Google Search engine built-in

Online English Chinese Dictionary

2006-10-16T23:48:00.001+08:00

Forget about that weighty hardcover Oxford English-Chinese dictionary or running virtual CD-ROM drive to read the CD-ROM edition of dictionary.

Dict.cn and Yahoo Dictionary perhaps are the most wanted online English-Chinese and Chinese-English dictionary.

Dict.cn is built by a group of Chinese (from China) who study at USA, and started to offer service since year 2003. Other than online Chinese-English and English-Chinese dictionary service, Dict.cn also offers some other good services, such as

Web browser-Dict.cn integration to consult Dict.cn dictionary service easily
Dict.cn Web API enable software developer to develop software with dictionary service provided by Dict.cn
Dict.cn widget allows webmaster to provide Dict.cn dictionary service easily in his/her website
Add MSN Robot MSN ID, that is dictcn021@hotmail.com, to MSN Buddies list! This robot is COOL enough! While chatting in MSN Messenger, IM a word to MSN Robot and the robot will nice to reply the dictionary definition or translated word back.
Find out other tools offered by Dict.cn from the link below

Yahoo Dictionary offers similar features of Dict.cn too. In case Dict.cn unavailable, Yahoo Dictionary could be the backup or vice-verse.

Some of the great features offered by these two goodies are

Easy to remember URL.
Reasonable fast search time.
Reasonable clear pronunciation.
Antonym and synonym.
Variants of the search term such as adjective, adverb, verb, etc.
Recent search term.
Auto-listing of words that match the initial characters of search term as typing goes.
List of words that have close spelling.

Related information:

Dict.cn is the valid URL - such a short and easy to remember web address of a online Chinese-English English-Chinese dictionary!
Dict.cn tools to find out how attractive is Dict.cn!
Yahoo English-Chinese Dictionary at HongKong
Yahoo English-Chinese Dictionary at Taiwan
Really simply and plain interface of English-Chinese dictionary
Really fast and simple interface of English-Chinese dictionary
For those who are looking for online resources of learning Cantonese and Mandarin, bookmark these two sites
1. Dictionaries of English-Chinese, Mandarin, and Cantonese
2. Online Chinese Tools has a list of tools and references of learning Chinese online
Search more related info with Google Search engine built-in

PDF Creator vs PDF Viewer

2006-10-16T16:23:00.001+08:00

PDF, shorts for Portable Document Format, is an open standard file format developed by Adobe Systems to represent 2D document. Being an open standard file format meaning that anyone may develop application to read and write PDF files without having to pay royalties to Adobe Systems.

PDF is both device independent and resolution independent as it doesn't encode information which is specific to software, hardware, or operating system used to create and view the document. This feature makes a valid PDF file rendering exactly the same regardless of its origin or destination.

Related information:

Adobe Reader is the freeware version of PDF viewer provided by Adobe System to view PDF document.
PDFCreator is an open source program distributed under GPL GNU license. Don't get it wrong, PDFCreator is not a program that able to edit PDF file as Adobe Acrobat which cost over hundreds pound.

PDFCreator is a PDF creator, a PDF writer, a PDF maker, a PDF printer, a document-to-PDF converter, etc, but not a PDF editor!

PDFCreator works exactly like a legacy ASCII file printer device. PDFCreator convert a document to PDF file format when the document is "printed". For example, after finish editing a nice resume in Microsoft Word 2003, click on the print function, select the PDFCreator as the target printer, turn on some great PDF file security features and password encrypted protection, press print button, and finally getting a soft copy of resume in PDF file format.

Why need to convert Word document to PDF? Besides the points at the top of this article, email both Word and PDF version of resume may make the recruiter more choice to read the resume, that the recipients may not using Microsoft Office at all!
Search more related info with Google Search engine built-in

Context Menu Create Date-based Folder

2006-10-16T13:12:00.001+08:00

Tired of creating date-based folder daily which is used to save daily reports? Why not create a shortcut on Windows Context menu to simplify the job?

Steps to create the shortcut on Windows Context menu

Click on the My Computer icon on the Desktop
Click on the Tools menu
Click on the Folder Options
Click on the File Types tab
Search for "Folder" file type and highlight it
Click the Advanced button
Click the New button
Type a meaningful name, say DateFolder, in the Action field
Type CMD.EXE /C MD "%1\%%DATE%%" in the Application Used To Perform Action field below the Action field
Click OK button all the way to complete the procedures
Click on the Start button
Click on the Settings menu
Click on the Control Panel
Click on the Regional Options
Click on the Date tab
Set the Short Date Format to a format of date without using characters which are not valid to be used for a file name, such as "/". A valid date format such as dd-MMM-yyyy
Click OK to save the changes, if any.
Now, it is done. Right-click on any folder and click on the DateFolder shortcut, that has just created, from the pop up Windows Context menu.
Bingo! There is a date folder named after the creation date insides the folder that being right-click just now!

Related information:

Enable MS-DOS auto-complete filename with TAB key and auto-change path quickly.
Search more related info with Google Search engine built-in

Linux Command To Confirm Bad Sector

2006-10-15T23:11:00.001+08:00

Hard disk being one of the vital components in computer system. Unfortunately, hard disk is also being one of the most high risk and sensitive components that is prone to failures, owed to the fact of mechanical subsystem attached!

The Linux command badblocks could be used to run bad sector burn-in test on a new or suspected faulty hard disk. Just get a low end PC or server installed with Linux OS, attach the target hard disk to the IDE or SCSI bus, and run the badblocks command on the target hard disk. For example,

badblocks -svw -t random -p 3 /dev/sdb

get badblocks to perform three rounds of destructive write of random data to the second SCSI hard disk.

Be careful! The option switch -w performs destructive write. Never use this option switch on a partition with filesystem. Instead, use -n to perform non-destructive read-write on a partition with filesystem!

Related information:

Search more related info with Google Search engine built-in

Checklist To Tune DB2 Performance

2006-10-15T19:50:00.001+08:00

DBA suggests few of the recommended database performance tuning tips for IBM DB2 database engine that is running on Linux server.

Linux kernel parameters tuning that applicable to DB2 version 8.1 and 8.2.

Executing command sysctl -A to print out current kernel parameters setting. Some of the notable are
- kernel.sem (Semaphore setting)
  Recommended Value : 250 256000 32 1024
- kernel.msgmni (Maximum system-wide queues)
  Recommended Value : 1024
- kernel.msgmax (Maximum size of messages in byte)
  Recommended Value : 65536
- kernel.msgmnb (Default size of queue in byte)
  Recommended Value : 65536
In order to retain these changes of kernel parameters on every system reboot, add the updated kernel parameters setting to /etc/sysctl.conf system file to do the great job.
DB2 database configurable parameters tuning.

After connecting to database called my_test_db by executing db2 connect to my_test_db, running another DB2 command db2 autoconfigure apply none to get DB2 database engine calculate the best recommended value of DB2 database configurable parameters. Some of the notable are
- LOGPRIMARY / LOGFILSIZ
  Larger log buffer required for OLTP workloads with high transaction rate.
- CHNGPGS_THRESH
  For databases with heavy update transaction workloads, make sure there are enough clean pages in the buffer pool by setting the parameter value equal to or less than the best recommended value calculated by DB2 database engine.
- LOCKLIST
  The amount of storage that is allocated to the lock list. Increase this value if lock escalations causing performance concerns, that logged as warnings in the db2diag.log file.
- DBHEAP
  Database heap per database. Needs to be increased for larger buffer pools.
- NUM_IOCLEANERS
  Large buffer pools require a higher number of asynchronous page cleaners.
Alternate page cleaning algorithm tuning.

DB2 UDB ESE v8.2 introduces a new buffer pool page cleaning algorithm which is not turned on by default. It is necessary to test this new page cleaning algorithm with the database workload. To turn on this alternate page cleaning algorithm, executing DB2 command

db2set DB2_USE_ALTERNATE_PAGE_CLEANING=YES

Related information:

Search more related info with Google Search engine built-in

Disable Linux Reboot On CTRL+ALT+DEL

2006-10-15T18:39:00.001+08:00

Don't ever press CTRL+ALT+DEL key combination in a Linux server!

Windows guys used to press CTRL+ALT+DEL key combination follow by ENTER key to immediately lock the server running on Windows 2000 or Windows XP and above when they leave the server.

What is the default behaviour when pressing CTRL+ALT+DEL key combination in a Linux machine? Well, the default action of Linux in responding to CTRL+ALT+DEL key combination is to reboot the Linux machine immediately! Just press it once, not twice as in Windows Me, and Linux will not be kind to ask confirmation before it really rebooting itself!

Anyway, this Linux default behaviour in responding to CTRL+ALT+DEL key combination pressed could be tweaked, indeed. Edit the /etc/inittab system file, look for the line containing ctrlaltdel keyword, and then either

Remark the line ca::ctrlaltdel:/sbin/shutdown -t3 -r now to disable Linux from responding to the CTRL+ALT+DEL key combination

or
Replace the /sbin/shutdown -t3 -r now with something else, such as

dialog --clear --title "Information" --msgbox "Don't press CTRL+ALT+DEL key combination in Linux machine.\n\nTo reboot server, use init 6 or init 0 to shutdown Linux." 10 40;clear

which use the dialog box command to alert users with a text-based GUI information dialog box.

Related information:

The dialog box command is not a standard program installed by most Linux distribution. Find the dialog package from respective Linux distribution and install it.
Search more related info with Google Search engine built-in

Which Command Is Linux Refer

2006-10-15T17:12:00.001+08:00

Opss! Executing ls command at keith login account displaying directories in blue color, executable file in green color, and plain text file in white color, etc.

But, when executing the same simple ls command at root login account does not differentiate file type by color scheme. How come?

Users who are familiar with shell built-in command alias will know that it is the alias that wrap the ls command with --color=none option switch. At the command prompt, type

alias | grep ls

will able to tell the fact of this.

The which command is used to find out which command the Linux shell interpreter is referring to in the current login session. The simple form of which command, such as which ls will show the path of the ls command without telling the alias name of it. Well, tweak which command with its command option switch and wrap it with alias command, such as this

alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'

Execute the which ls again, will now able to show both the ls command path and the alias of it, as shown in the diagram.

Related information:

Use the alias command to shorten the long Linux command
Using the ls command by examples
Search more related info with Google Search engine built-in

alias Shorten Long Linux Command

2006-10-15T01:27:00.001+08:00

Tired of typing Linux command because of long list of command option switches? Try to use the command alias to relieve tired of typing long Linux command then.

As the command name suggests, the Linux shell built-in command alias allows a user-defined command to represent

A system command with long arguments, such as

find . -type d -print

This find command used with a long option switches to list all directories that exists from the current directory downwards. The find command could be rather long if more find command option switches applied.

This long command line could be made simple with an alias, such as

alias dirfind='find . -type d -print'

that allows user to execute the short user-defined command dirfind instead of typing out that long command line.
A series of system commands, such as

tar -zcvpf bin.tgz bin; [ $? -eq 0 ] && echo DONE || echo FAIL

These system commands execute sequentially, aim to check the tarball archive creation status upon its completion. If success then echo DONE else echo FAIL.

Again, by using the alias command could make it shorter and simple enough, such as

alias chkbkp='tar -zcvpf bin.tgz bin; [ $? -eq 0 ] && echo DONE || echo FAIL'

where the user could execute chkbkp at command prompt and the Linux shell will expanding it to that commands series.

Related information:

It is not advisable to declare and use alias in shell scripts. It is better to use a variable or a function for the purpose. Anyway, if insist, it is technically possible to use alias in shell scripts by turning on shell scripts option shopt -s expand_aliases before declaring and using an alias inside the shell scripts, such as the sample in diagram below.

By default, the parent shell where a shell scripts executed will always spawn the scripts execution into a subshell, unless explicitly run the shell scripts in the current shell environment. Shell scripts that is running in subshell will not able to use aliases defined in parent shell environment!

To run a shell scripts in current shell environment instead of spawning into subshell, use one of these two syntax

source testscripts.sh
or
. testscripts.sh

In Linux system, there is a file named .bashrc in each home directory. Use this file to define aliases, which will make the defined aliases effective on each login.
The login profile .bash_profile could also be used to define aliases. In fact, it is the .bash_profile which execute the .bashrc while a user login.
To remove an alias, simply use the shell built-in command unalias, such as unalias chkbkp
To list all the aliases defined in the current login session, just type the command alias at the command prompt will do.
Which command is the Linux shell refers to
Search more related info with Google Search engine built-in

Booting Thin Client Diskless Workstation

2006-10-14T23:29:00.001+08:00

Bootp, shorts for Bootstrap Protocol, is an UDP network protocol which is originally defined in RFC 951 to assign IP address for network clients. Bootp is well suitable to apply in diskless workstation, workstation without operating system installed, or simply called thin client.

Bootp is not DHCP! Although both of these two protocols sound similar at first thought, but they are technically different and could be co-exists in the same server or network segment.

Hospitality management system giant, Micros System Inc, makes good use of bootp in its high rank Point-Of-Sale system called Micros 8700 HMS.

When the diskless Micros PC Workstation power on, the bootp enabled network interface card will broadcast its MAC address to the network. When the bootp daemon running on the Micros host receives the broadcast packets, it will assign a valid IP address follow by transferring a DOS operating system image to the PC Workstation according to the MAC-IP-Image mapping maintained in the bootpd configuration file.

Once the image transferring (via tftp protocol) completed, the diskless PC Workstation starts to boot up with the OS image parking in memory segment that act as RAM-DISK. When the boot up completed, the Micros diskless PC workstation functions as if it is a normal desktop PC pre-installed with DOS OS.

Bootpd server and clients could be reside on different network segment by deploying bootp relay agent. To make thing simple or get it up and running right during initial roll out, put both bootpd server and client on the same network segment.

Checklist when thin client unable getting IP address:

Replace a known good unit of thin client to rule out possibilities of

Faulty boot ROM embedded in NIC that is bootp enabled
Faulty Ethernet patch cable
faulty network access point or LAN point

Bootp daemon is not running. In Linux/Unix, execute

ps -ef | grep bootpd
or
lsof -i | grep 67

to confirm bootp daemon is running and listening to legacy port number (as shown in /etc/services file)
Incorrect MAC address to IP address mapping maintained in /etc/bootptab bootpd configuration file
ARP cache conflict at bootpd server. Executing the command

arp -a

to list the bootpd server arp cache. Confirm that there is no ARP cache conflict. To delete the conflict, for example conflict on IP address 192.168.1.3, execute command

arp -d 192.168.1.3
Use cross-over patch cable or straight Ethernet cable and a hub to directly link up the bootpd server and client to form an simple isolate network. If it works in this simple network infrastructure, then get network experts sit in for assistant. There might be firewalls or routers that have blocked the UDP packets from reaching to bootpd server.

Related information:

Tftp protocol in brief

Host A sends an read request (RRQ) or write request (WRQ) packet to host B. The packet containing the filename and transfer mode.
Host B replies with an acknowledgement packet (ACK) to WRQ or directly with a DATA packet in case of RRQ. The reply also serves to inform host A of which port on host B the remaining packets should be sent to.
The source host sends numbered DATA packets to the destination host, all but the last containing a full-sized block of data. The destination host replies with numbered ACK packets for all DATA packets.
The final DATA packet must contain less than a full-sized block of data to signal that it is the last. If the size of the transferred file is an exact multiple of the block-size, the source sends a final DATA packet containing 0 bytes of data.

Search more related info with Google Search engine built-in

Repair Corrupted Outlook PST OST File

2006-10-12T08:47:00.001+08:00

PST, known as Microsoft Outlook personal folder file or email archive file, used to archive emails out from the mail box at server side to a local storage or network drive.

OST, known as Microsoft Outlook offline folder file, allows user to work with Microsoft Exchange mail box in an offline mode. For example, emails composed, Contacts or Calendar changes, etc, will be storing in the offline folder. These changes made in offline folder will be automatically synchronize with Microsoft Exchange Server once hook up to the network - emails composed will be sending out immediately and Contacts or Calendar changes are updated to server side objects.

Both the Microsoft Outlook PST and OST files are believed using MSDE database engine.

MSDE is a light-weight freeware version of Microsoft SQL Server database engine that Microsoft offers to attract database users (especially MS Access users, developers, students, educators, etc) to develop database projects using Microsoft SQL Server. The latest release of MSDE is called SQL Server Express edition.

MSDE built with limitation of accessing up to 2GB worth of data only. The same limitation occurs in MS Outlook PST and OST file as well!

Watch the size of PST and OST file! If they getting fatty, trim them down quickly to save archives of email from hitting the 2GB limitation or a file corruption will happened soon! The best practice is to create multiple PST or OST files to categorize email archives. For those email with attachment, it is easily reaching the 2GB limitation. So, more PST or OST files are needed to archive such emails with attachment!

Office 2000 and higher with latest patches installed is nice enough to alert users with an error message and disallow users from adding or receiving new email item, so to safeguard PST or OST file to become oversize and corrupted. Earlier versions of MS Outlook does not display any error or warning messages and allow users to oversize the PST or OST file until corruption!

Microsoft offers a tool called PST2GB to recover a MS Outlook PST file that is corrupted after storing over 2GB worth of data. Microsoft alleged that PST2GB is not a tool that is 100% work at all time! If PST2GB does work, it does not recover all of the data (the truncated data is missing).

PST2GB merely create a truncated copy of the PST file to under 2GB. The copy that is left after the PST2GB completes does not have all the original data because the PST2GB forcibly cuts a user defined amount of data (below 2GB) from the PST file.

In brief,
Data or the emails archive after the truncation boundary will gone missing.
There must be enough disk space, 2GB free disk space if as maximum as possible of recovery desired.

Steps to recover corrupted PST file as per Microsoft KB296088 (applied to MS Outlook 97 to MS Outlook 2002)

Download the PST2GB from Microsoft Download Center
Extract the downloaded file 2gb152.exe to an empty folder for these five files - Msstdfmt.dll, Msvbvm60.dll, Pst2gb.exe, Readme.rtf, Readme.txt
Start the Pst2gb.exe program.
Click Browse to select the oversize PST file and then click Open.
Click Create, select the name and location of the truncated data file to be created, and then click Save.
Enter the amount of the data that intended to truncate in the PST file. There is no absolute ideal figure for this but for the best results is using 20 to 25MB, more or less. If that works, repeat the process and truncate the original oversize PST file by only 15MB. If that works, then try the process with 5MB. If 25MB does not work, repeat the process and truncate the original PST by 35MB. If the process does not work, increase the amount until the process is successful.
Run the Inbox Repair Tool scanpst.exe on the smaller PST file.
Open the repaired PST file in Microsoft Outlook.
(Recommended but optional) If the file opens, right-click the root folder of the PST, click Properties, and then click Compact Now to start the compression. For a file of this size, the compression may take approximately 4-8 hours.
If the file does not open, discard the truncated PST file, and repeat the process with the original PST file. Truncate more data than in the first attempt, and try the process again.

If the following error message arise when trying to run the PST2GB Utility

Run-time Error '713': Class not Registered. You need the following file to be installed on your machine. MSSTDFMT.DLL

To resolve this error, follow these steps:

Microsoft Windows 98, Microsoft Windows 98 SE, Microsoft Windows ME

Copy the MSstdfmt.dll file to the C:\Windows\System folder.
Open a command prompt, and then type the following command

REGSVR32 C:\Windows\System\MSSTDFMT.DLL

Microsoft Windows NT, Microsoft Windows 2000, and Microsoft Windows XP

Copy the MSstdfmt.dll to the C:\<windir>\System32 folder.
Open a command prompt and type the following command

REGSVR32 C:\<windir>\System32\MSSTDFMT.DLL

where <windir> is either the WINNT or the Windows directory.

Related information:

PST2GB from Microsoft official download site
Inbox Repair Tool for MS Outlook 2000 to MS Outlook 2003
Inbox Repair Tool for MS Outlook 97
Inbox Repair Tool for MS Outlook 98
OST Integrity Check Tool for Outlook 2000
Mailbox Recovery for Microsoft Exchange 2000 Server
Search more related info with Google Search engine built-in

lsof Identify Resource Locked Process

2006-10-11T23:44:00.001+08:00

Samba server comes with a handy utility called smbstatus to report users who are holding the shared resources.

Utilities used to find out processes that are locking system resources are among the most wanted system utilities for experienced users and system administrators. The lsof being one of such excellent utility that used to identify process or user that is locking system resource such as file or network socket.

For example, a system administrator could use the lsof -i to easily understand how the IBM MQ server communicate over the TCP/IP network with IBM Informix server. The lsof output, as in the diagram below, shows that the Informix oninit is listening to a user defined mnemonic port name stp which the IBM MQ server communicate with. The /etc/services system files is usually used to map a numeric port number to a descriptive port name defined by user.

Execute lsof -i TCP to report all processes that are accessing the TCP sockets found on the system
Execute lsof -i tcp:8080 to find out what process is holding TCP port 8080.
Execute lsof without any command options to list system wide resources that are using by processes running in the system.
Execute lsof -p 456 to show all resources that are being held by process id 456
Some programs might running on the Linux system by more than one instance. In this case, type lsof -c ProgramName instead of lsof -p PID to get a broader scope of view. For example, lsof -c squid to find out what are the resources held by all squid processes running on the system.
Execute lsof -u keith to confirm resources that are being held by user id keith
Execute lsof /home/keith/secretfile to find out what are the processes that are locking the specify file /home/keith/secretfile

Related information:

Another utility called fuser has similar features as of lsof utility. Executing fuser -m /media/cdrom will report all process id that are holding the specify resource.

Each of the process id suffix with an ASCII character code which represent the resource access type. These resource access type codes are not standardize among various Linux distributions. To be safe and accurate, always consult the fuser man page to confirm the code definitions.

To check out what process ID is using TCP port 8080, execute the fuser as fuser -n tcp 8080 or fuser 8080/tcp
The native network related Linux command netstat is a good tool to find out what program or command is binding to a TCP and UDP port. For example, there are Bind, Djbdns, etc, used to bind with port 53 for DNS protocol. By executing netstat command as

netstat -tulap

will shows both the program and process id that bind to the network port. The diagram below shows the commands output of lsof vs netstat.

Both of the commands displaying pseudo port name instead of numeric port number, where the mapping of pseudo port name and numeric port number is defined in /etc/services file.

The netstat command, however, able to display numeric port and IP address with -n option switch. For example, rewrite the command as netstat -tulapn

Note! Both netstat -tulap and lsof -i MUST be executed with root user account privileges, else nothing as those in the diagram above will be seen.
Search more related info with Google Search engine built-in

Repair Corrupted Windows Boot.ini

2006-10-10T23:27:00.001+08:00

Boot up to Windows Recovery Console and execute command bootcfg to repair corrupted or recreate missing Windows boot.ini file.

The bootcfg command able to scan hard disks for installation of Windows NT 4.0 and above and then add them to existing boot.ini file. The command also able to rebuild a new boot.ini file if one does not exist.

A brief of bootcfg command usage and syntax

bootcfg /add scans the computer for Windows systems installed (for example Windows 2000 and Windows XP in a dual boot setup), displays the results to choose and add it to the Boot menu.
bootcfg /rebuild iterates through all Windows installations found in the PC, allows user to specify which installations to rebuild the boot.ini file.
bootcfg /list reads the boot.ini file and displays the operating system identifier, the operating system load options, and the operating system location (path).

Related information:

The bootcfg command syntax and usages
Search more related info with Google Search engine built-in

Sending Windows Console Message

2006-10-10T22:43:00.001+08:00

Windows Me or 9x comes with one handy network chatting program called Winpopup. Simple GUI allows user at one computer to chat over the network with counterparts sitting at another networked Windows.

However, there is not similar Winpopup replacement for Windows 2000 and above. There are two ways to send a message, better known as console message or Windows Alerts, to networked system running Windows 2000 and above.

Via the Computer Management window

Right-click on the My Computer icon on Desktop
Click on the Manage option from the pop up context menu
Click on the Action menu of Computer Management window
Goto All Tasks option
Click on the Send Console Message... option to call up Send Console Message window.

Via Command Prompt

Click on the Start button
Click on the Program menu
Click on the Accessories menu
Click on the Command Prompt application
At the Command Prompt window, type

net send 192.168.1.2 "testing messages"

to send a messages "testing messages" to PC with 192.168.1.2 IP address.

It is possible to replace IP address with DNS name or domain name to send console message to all workstations of the said domain.
Type net help send for more syntax and usage information.

Related information:

Search more related info with Google Search engine built-in

Restart VNC Remotely

2006-10-10T20:26:00.001+08:00

Opsss! Can't VNC over to remote hosts!

Might need to restart the VNC server, but how?

Restart Windows-based (Windows 2000 and above) VNC server

Right-click the My Computer icon on Desktop
Click the Manage option from the pop up context menu
Click the Action menu of the Computer Management windows
Click the Connect to another computer... option
Type the IP address or DNS name of the target PC running the VNC server
Enter the login authentication info when prompt
After connect successfully, click the Services and Applications on the left panel.
Click the Services option
Search for VNC Server service on the right panel, right-click on it, and click Restart option to restart the VNC server.

Restart Linux-base VNC daemon

Telnet or ssh over to target host that running the VNC daemon
Type the command vncserver -kill:1 to kill the VNC daemon running on DISPLAY:1, for example.
Type vncserver :1 to bring up the VNC daemon running on DISPLAY:1 again.
To ensure VNC daemon startup listening for connection, type

netstat -ant | grep 5901

where 5901 is the legacy VNC daemon listening port of DISPLAY:1 in the previous step. If the port is open and listening means that VNC daemon is up and running successfully.

Related information:

Running VNC daemon on Linux
Search more related info with Google Search engine built-in

MD5 Shell Scripts Find Duplicate Files

2006-10-10T13:34:00.001+08:00

The shell scripts wrap the default md5sum program found on most Linux system to prepare a report of unique and duplicate files in a given directory.

The lengthy source code could be shorten if removing the DupUniRpt function which merely used to prepare an easy to read report that showing both the filename and number of duplicate and unique files.

By removing the DupUniRpt function call and function coding, do remember to add the line

cat $FM5L

right after the DupUniRpt function call in the if-else statement. The $FM5L is a semi-raw report file that groups duplicate and unique files together.

The wDupUniRpt.sh contain the same source code of DupUniRpt function source code, which could be used to prepare that easy to read report based on the semi-raw report file. This shell scripts created merely for easy debugging purpose.

Both these shell scripts have been tested successfully with as much as possible scenarios. The source code might be able to further enhanced for efficiency or bugs fixing if any. Any suggestive comments are greatly appreciated.

Related information:

wmd5.sh to report both filename and number of duplicate and unique files in a given directory
wDupUniRpt.sh used to report redundant and unique records in an ASCII file of sorted records.
MD5 checksum used to find redundant files
Search more related info with Google Search engine built-in

Install Recover Console To Boot Menu

2006-10-09T23:06:00.001+08:00

Recover Console is not install to local hard disk by default during Windows installation.

In order to access to Recovery Console, normally practice is to boot up the system from the appropriate Windows setup CD. If the system is running on Windows XP, use the Windows XP setup CD. Note that Recover Console only available in Windows 2000 and above.

Other than access the Windows Recovery Console from bootable Windows setup CD, it is possible to install the Windows Recovery Console to local hard disk and configure it to appear as one of the Windows boot up option.

Install Recovery Console to local hard disk and enable Recovery Console as part of the Windows boot up menu option:

Click on the Start button
Click on the Run menu
Type D:\i386\winnt32.exe /cmdcons by assuming D: drive is CD-ROM drive letter in which the Windows XP Setup CD is loaded.
Click OK button and then follow the instructions on the screen to complete the straight forward setup and restart the computer at the end of setup process.
After the Windows reboot, edit the file C:\boot.ini with notepad editor. Note that this file is hidden system file which is not "appear" in Windows Explorer by default, unless turning on the view hidden file options.
If view hidden file option is not turn on, turn it on by

Open My Computer
Click on the Tools menu
Click on the Folder Options
Click on the View tab
Click on the Hidden files and folders
Click to select Show hidden files and folders option button.
Click to clear Hide protected operating system files check box
click OK to complete the turning on view hidden file procedures.

At the bottom of the file, append this line

C:\cmdcons\bootsect.dat="Recovery Console" /cmdcons

Note that changing the description "Recovery Console" to whatever meaningful name is possible.
Save and exit the edited file. On the next system boot up, notice that there is one new boot option called Recovery Console in the Windows boot up menu.

Related information:

Tweaking Windows Recovery Console
Search more related info with Google Search engine built-in

Using ls Command By Examples

2006-10-09T22:01:00.001+08:00

The ls command is a Linux command that is used to list directory contents. In fact, it is a standard shell command that exists in all Unix/Linux variants.

Using ls command by examples

To list all files in ascending order of file name detailed with file modification time

ls -la
To list all files in descending order of file creation time in full or customized date-time format

ls -lact --full-time
ls -lact --time-style="+%d %m %Y"
To list all files in descending order of file creation time

ls -lact
To list all files in descending order of file size in kilobytes

ls -laSh
To list only directories

ls -ap | grep /
or
ls -al | grep ^d

Alternatively, use the find command as

find . -type d -print
To list only directories initial with rpt filename

ls -al rpt* | grep :$
or
find . -type d -name "rpt*" -print

Definition of ls file listing command option switch

option switch l used to list files in long listing detailed format.
option switch a used to list all files including hidden files which filename prefix with a dot.
option switch lct used together to list file in descending order of file creation time.

option switch lc list file creation time and sorted by filename.

option switch lt list file in descending order of file modification time.
option switch h used to list files size information in kilobytes (KB).
option switch S used to list files in descending order of file size in byte.
option switch r used to reverse the default of descending listing order to ascending listing order.
option switch --full-time or --time-style used to display time-related info in full or customized format.

Notes! If the ls command colour scheme is not easy to read, turn it off by either:

On ad-hoc basis by adding option switch. For example

ls /etc --color=none

to list /etc directory contents without color scheme turning on. OR
On selective login session only. Use the alias command to save typing efforts. For example, execute the command

alias ls="ls --color=none"

will cause subsequent ls command executing as if it is supplied with --color=none option switch and automatically turn off the color scheme.
On each login session of individual login acount only. Copy the file /etc/DIR_COLORS to the user home directory as $HOME/.dir_colors and edit the variable COLOR to become COLOR=none to do the job.

From the next user login onwards, type the command set | grep COLOR will notice that the COLORS variable changed as specified in the $HOME/.dir_colors setting file. Typing the ls command as usual which will disable the file listing color scheme automatically.

To turn on the color scheme again, simply rewrite the line COLOR=none to COLOR=tty or COLOR=auto will do.

The file /etc/DIR_COLORS is used to control file listing color scheme globally, meaning that all users account will be affected.

Related information:

Creation time vs modification time at Linux file creation time vs Linux file modification time section of Using find command by examples article.
Search more related info with Google Search engine built-in

Microsoft Freeware Visual Studio Express

2006-10-06T06:27:00.001+08:00

Yes! Effective 19 April 2006, all Visual Studio 2005 Express Editions are free permanently!

Microsoft Express Edition includes a wide range of Microsoft flagship development tools such as MS SQL Server 2005, Visual Basic 2005, Visual C# 2005, Visual C++ 2005, Visual J# 2005, Visual Web Developer 2005. As long as Express keyword attached, such as Visual Studio 2005 Express Editions, it is a genuine Microsoft freeware edition.

For those who familiar with MSDE, SQL Server Express is the replacement. Microsoft alleged that the name MSDE was confusing to customers and partners because many did not realize that it was associated with SQL Server. By changing the name from MSDE to SQL Server Express there will be less confusion among customers and partners.

Everyone could use the Expression edition at no cost for the purpose of testing, learning, and even compile and sell the development project. Before this, Microsoft freeware such as Visual Basic Learning edition couldn't compile development into executable.

Related information:

Product comparison of Visual Studio 2005
Visual Studio Express frequently asked questions
Price comparison of Visual Studio 2005 products
Search more related info with Google Search engine built-in

File Command Guess Linux File Type

2006-10-03T21:09:00.001+08:00

By convention, Windows system using 3 alphanumeric characters to serve as file extension. File extension telling Windows OS how to deal with the file, what program to manipulate the file, and to Windows users easily recognize a common file type.

There is no such strong concept of file extension in Linux as well as UNIX world. Linux folks, however, do practice to use file extension for some file formats such as compression or archive file format. Windows users might easily get cheated by file extension trap in Linux.

For example, it is perfectly fine to rename a PKZIP compatible zip file called backup.zip to backup.tgz or whatever filename. Later, if the user simply executing tar -zxvf backup.tgz might either get errors or see nothing and thought the file is corrupted.

Wait! Before deleting the file which thought to be corrupted, use the file command to inspect the file type first.

Type file backup.tgz at the command prompt, it shows that backup.tgz is actually a PKZIP compatible zip file. So, user should executing unzip backup.tgz to extract the zip file or rename backup.tgz to backup.zip before executing the unzip command.

Related information:

Search more related info with Google Search engine built-in

Linux Archiving And Compression Command

2006-10-03T13:39:00.002+08:00

There are dozen of Linux commands or utilities used to archive files and compress data.

Take note that archive command (cpio, tar, etc) is different than compression command (zip, gzip, bzip, etc) from the technical points of view. Although both archive command and compression command could be used to backup files or filesystem.

Archive command simply group files together into one archive file without performing compression. Compression command group files together into one file which is compressed to reduce overall file size.

Also, take note that different archive and compression utilities have different advantages and disadvantages.

Following are some of the common command syntax that should be good enough for most file backup and data compression usage. Most of these syntax are portable to other UNIX or Linux variants.

The cpio archive command syntax:

Backup /home/keith/f1 and /home/keith/f2 directories recursively into cpio archive file format that named /home/keith/f1f2.cpio

find /home/keith/f1 /home/keith/f2 -depth -print | cpio -ocvB -O /home/keith/f1f2.cpio

If real full path is used, the file extraction has to be in real full path as well! This could be confirmed when listing cpio contents with -t option.

Example in step 1 could be more effective by first changing path to /home/keith and executing step 1 command as

find f1 f2 -depth -print | cpio -ocvB -O f1f2.cpio

In this case, relative path instead of real full path is used.

Using relative path is much safer and advisable as this helps to extract file relatively easier and reduce mistake of overwriting original file during file extraction.

Extract only f2 directory contents from f1f2.cpio archive file

cpio -icvdBum -I f1f2.cpio f2/*
Extract only file1 file in f2 directory from f1f2.cpio archive file

cpio -icvdBum -I f1f2.cpio f2/file1
List or view the contents of f1f2.cpio archive file

cpio -t < f1f2.cpio

The tar archive command syntax:

Backup f1 and f2 directories recursively and preserve files permission into tarball file named bkp.tar

tar -cvpf bkp.tar f1 f2
Extract all the contents of bkp.tar archive file

tar -xvpf bkp.tar
Extract only f1 directories and files underneath from bkp.tar archive file

tar -xvpf bkp.tar f1/*
Extract only file1 file in f2 directory from bkp.tar archive file

tar -xvpf bkp.tar f2/file1
List the contents of bkp.tar archive file

tar -tvf bkp.tar
Backup f1 and f2 directories recursively as well as compressing the tarball with either
- gzip compression utility by using -z option
- bzip compression utility by using -j option
To ease of file type recognition, Linux folks usually
- suffix filename of gzip compressed tarball with tar.gz, .tgz, .taz, or tar.Z
- suffix filename of bzip compressed tarball with tar.bz2
tar -zcvpf bkp.tgz f1 f2 to create gzip compressed tarball
tar -jcvpf bkp.tar.bz2 f1 f2 to create bzip compressed tarball
Extract all the contents of compressed tarball

tar -zxvpf bkp.tgz to extract gzip compressed tarball
tar -jxvpf bkp.tar.bz2 to extract bzip compressed tarball
List the contents of compressed tarball

tar -ztvf bkp.tgz to view contents of gzip compressed tarball
tar -jtvf bkp.tar.bz2 to view contents of bzip compressed tarball

The zip compression command syntax:

Most of the Linux/Unix-based zip utility is PKZIP compatible. So, most Windows-based zip program able to deal with Linux/Unix-based zip file, and vice-verse.

Compress f1 directory into zip file named f1.zip and encrypting the zip file using the -e option

zip -e f1.zip f1/*
Decompress only file1 file from f1.zip

unzip f1.zip f1/file1
Decompress all files from f1.zip

unzip f1.zip
View the contents of f1.zip

unzip -l f1.zip

The gzip compression command syntax:

Compress file1 into gzip compressed file named file1.gz (gz as default suffix given by gzip if not explicitly specify)

gzip file1
Decompress file1.gz

gunzip file1.gz

Gzip unable to gzip folder directly. Use tar command with -z option to gzip a folder.

The bzip compression command syntax:

Compress file1 into bzip compressed file named file1.bz2 (bz2 as default suffix given by bzip if not explicitly specify)

bzip2 file1
Decompress file1.bz2

bunzip2 file1.bz2

Bzip unable to bzip folder directly. Use tar command with -j option to bzip a folder.

Related information:

Compare and find the best compression format
Search more related info with Google Search engine built-in

Understand And Configure Linux Printer System

2006-09-26T14:53:00.001+08:00

Starting Redhat 7.3, Redhat Linux support two type of printing system known. These two subsystem are known as LPRng and CUPS respectively.

LPRng printing system, Redhat default printer subsystem, provides printconf as printer manager utility to configure /etc/printcap configuration file, printer spooler, etc.

While at command prompt, executing printconf-tui (Redhat 7.3) or redhat-config-printer-tui (Redhat 8.0) to bring up command line version of LPRng printing manager.

For the graphical version, click on the Main Menu => System Settings => Printing or type redhat-config-printer or printconf-gui at a XTerm or Gnome terminal shell prompt to bring up the same GUI program.
CUPS, shorts for Common UNIX Printing System, is an Internet Printing Protocol-compliant system for UNIX and Linux. CUPS printer subsystem uses the printer manager utility called lpadmin to configure /etc/printcap configuration file, printer spooler, etc. If CUPS is not the default printer subsystem, launch the Printer System Switcher application by executing the command redhat-switch-printer and set CUPS as the new default printer subsystem.

To allow only a few selected users to use a printer called inkjet-graphic, execute the command lpadmin -p inkjet-graphic -u allow:keith,jazz,alice and these setting will be updated to /etc/cups/printers.conf configuration file.

Note! The printer manager utility, printconf or lpadmin, saves any printer configurations made to the /etc/printcap setting file. If there is a need to make any printer configurations outside the printer manager utility, add them to the /etc/printcap.local file. The /etc/printcap file will be deleted whenever the printer manager executing or a server reboot.

Steps to add new printer is almost the same among printer manager utilities. In brief, these are the key points to get it works:

Give a descriptive queue name to distinguish the new printer with other printers or network resources, such as keith_laser, boss_laser, tenfloor_inkjet, etc.
Choose the appropriate printer queue type, such as LOCAL queue type for local physical attached printer, JETDIRECT for jetdirect printer, etc.
If there is option to select the Printer Device, rescan the devices for the correct device, or create a custom device. This will be the /dev entry that represents the interface between the device driver and the printer itself. In most instances, the device will be named /dev/lp0.
Choose a Printer Driver by selecting one from the extensive list. Drivers marked with an asterisk (*) are recommended drivers. If to configure remote printer or printer that does not have a corresponding driver in the list, the safest choice would be Postscript Printer. For JetDirect printers, Raw Print Queue is recommended.

To enable local printer sharing for remote host:

In local host which the printer attached, edit the /etc/lpd.perms configuration file to add in one line that will read ACCEPT SERVICE=X REMOTEHOST=</etc/host.lpd and make sure it should added before the line containing REJECT SERVICE=X NOT SERVER.
In the local host as well, edit the /etc/host.lpd printer access control file add in the full qualify DNS host name or IP address, one record per line, of hosts that are allowed to share the printer attached.
At the remote host, add the network printer as adding local printer except one has to choose a Unix Printer queue type and type the print server hostname and port (usually 631).

Related information:

LinuxPrinting.org is a database of documents about printing, along with a database of nearly 1000 printers compatible with Linux printing facilities.
Linux printing how-to from the Linux Documentation Project.
Search more related info with Google Search engine built-in

Redhat Enterprise Linux System File Permission

2006-09-25T22:19:00.001+08:00

Redhat Enterprise Linux device file permission could not be changed simply by using the chmod command. Instead, the device file permission is set by udev hotplug subsystem which is included in almost every 2.6 kernel based Linux distribution that is shipping.

The configuration file /etc/udev/permissions.d/50-udev.permissions defines the permission of each devices present in the Linux system. For example,

To change the raw devices file permission, search for the line that read as raw/*:root:disk:0660
To change tape drive file permission, search for the line that read as st*:root:disk:0660

The default permission defined is 0660. Simply change the 4 digits code as usual to an expected permission, say 0666 instead of 0660.

Related information:

Search more related info with Google Search engine built-in

System And Network Monitoring Freeware

2006-09-25T11:55:00.001+08:00

Nagios is the answer!

It is licensed under the terms of the GNU General Public License Version 2 as published by the Free Software Foundation.

Nagios is a powerful system and network monitoring application. It monitors hosts and services specified, alerting administrators when threshold triggered, and when they recover to healthy state.

Nagios is only available in Linux or UNIX variants. Although, it could helps to monitor Windows servers as well via the Windows version of Nagios client.

Nagios features:

Monitors network services such as SMTP, POP3, HTTP, NNTP, PING, etc.
Monitors server resources such as processor load, disk usage, etc.
Simple plugin design that allows users to easily customize own service checks.
Parallelized service checks.
Ability to define network devices hierarchy using "parent" hosts, allowing detection of and distinction between network devices that are down and those that are unreachable.
Notifications to contacts of email, pager, or user-defined method, when service or host status change.
Ability to define event handlers to be run during service or host events for proactive problem resolution.
Automatic log file rotation.
Support for implementing redundant monitoring hosts.
Optional web interface for viewing current network status, notification and problem history, log file, etc.

Related information:

Nagios official site
Nagios 2.0 documentation
Nagios Plugin is the open project at Source Forge to create Nagios plugin
Nagios Exchange is the official repository for third party Nagios plugin
Nagios plugin development guidelines
Search more related info with Google Search engine built-in

Internet Explorer Turns FTP Browser

2006-09-25T00:12:00.001+08:00

FTP is a legacy file transfer protocol that has been widely used since the day of networked computing.

Other than using the serious typing of command line FTP client, such as the standard FTP client offers by all Windows system, Internet Explorer able to serve as GUI FTP browser too!

Follow these simple steps to turn IE into a graphical FTP client:

Click the Tools menu from Internet Explorer,
Click on Internet Options,
Click the Advanced tab,
Check the check box labeled as "Enable Folder View For FTP Sites",
Check the check box labeled as "Use Passive FTP". Set this option only if the PC is behind a firewall.
Click OK button to complete the setting.
Now, IE is ready to serve as graphical FTP browser. For example, type ftp://keith@188.8.1.10 in the IE address bar and press ENTER to instruct IE connect to FTP server 188.8.1.10 using FTP user account keith. Enter the password when prompt.
Click OK and wait. After successful authentication, an interface similar to Windows Explorer shown. Copy files or folders as usual!

Related information:

Search more related info with Google Search engine built-in

Tweaking Windows Recovery Console

2006-09-23T00:04:00.001+08:00

The Windows Recovery Console is designed to help system administrators recover Windows-based computer that fails to start up properly. It is available only in command prompt. Hence the name "Console" attached. It looks like the Windows 9x boot disk, but Windows Recovery Console is more powerful and features rich than the old Windows boot disk.

Basically, Windows Recovery Console allow system administrators to:

Copy, rename, replace, and access to operating system files and folders
Enable or disable Windows services for next system bootup
Repair the file system boot sector or the Master Boot Record (MBR)
Create and format partitions

By default setup, Windows Recovery Console with Administrator account logon allows access to only

the root folder
the %SystemRoot% folder and sub folders of the Windows installation
the Cmdcons folder
the removable media drives such as the CD-ROM drive or the DVD-ROM drive

Trying access to folders other than those listed above will rejected with an "Access Denied" error message. Besides that, Windows Recovery Console disallow copy files from local hard disk to removable storage such as floppy disk. However, Windows Recovery Console allow copy files from removable storage to local hard disk or copy files from one hard disk to another hard disk.

Although, limitations imposed on default setup that stated above could be resolved by

First, enable setting in Local Security Policy.
1. Click on Start button,
2. Click on Run menu,
3. Type gpedit.msc and click OK button,
4. Click on Computer Configuration, Windows Setting, Security Setting, Local Policies, Security Options,
5. Look for "Recovery Console: Allow floppy copy and access to all drives and all folders" policy on the right pane and double-click it,
6. Select Enabled,
7. Click OK
Note! As a security measures, it might be wise to double-click on "Recovery Console: Allow automatic administrative logon" policy too and disable it.
Second and last, boot up to Windows Recovery Console, logon with Administrator login account, and execute these two commands:
1. set AllowRemovableMedia = true
2. set AllowAllPaths = true
3. set AllowWildCards = true to allow wildcard support for some commands such as del.
4. set NoCopyPrompt = true to disable prompt when overwriting an existing file.

Related information:

Install Windows Recovery Console
Search more related info with Google Search engine built-in

Shell Scripts Monitoring Disk Space Utilization

2006-09-22T23:31:00.001+08:00

Nothing special. Just a simple shell scripts, could be served as an introduction of Unix Shell scripts programming, written to check disk space utilization of Linux (applicable to Unix too) filesystems or partitions.

Note! Ignore the left most numeric digits which are not part of the Shell scripts coding. These are line number indicators, which could be turned on in Vi editor using the :set nu command code.

It might be useful to comment out line 14th and remove the hash key on line 15th, which disable echo alert to console and enable alerts emailed to mail box. Configure Linux scheduler via the crontab -e to run this shell scripts, perhaps once a day, and get system administrators alarmed of critical free disk space before the system comes to halt.

Related information:

ChkFreeSpace.sh shell scripts source code
Vi editor quick cheat sheet
Search more related info with Google Search engine built-in

Restart Disabled Windows Services

2006-09-19T22:53:00.002+08:00

What could be done besides rebooting Windows server when a particular Windows service become unavailable to start, stop, pause, resume, or restart?

Restarting a Windows service, particular a poorly coded third party Windows service, may turns out to become unable to start, stop, pause, resume, or restart, after the service timeout and fail to startup successfully again. All these five common actions or tasks are dimmed and become unavailable. Restart the Windows server is not the only way, and might not advisable too, to resolve the problem.

Try this before deciding to reboot the Windows server:

Right-click on the Windows service,

Select property,

Set the Startup type to Disabled,

Click OK,

Set to Startup type again to either Manual or Automatic,

Click OK again,

Now, this particular Windows service might able to perform one of the five common actions again. Restart the Windows server if these do not work perfectly too.

Fine Tuning Nagios Performance

2006-09-19T09:31:00.002+08:00

These optimization tips are suggested by Nagios official documentation. It might be useful to fine tune Nagios for optimum performance and effective monitoring service.

Enabling aggregated status updates with the aggregate_status_updates option to greatly reduce the load on the monitoring host especially when monitoring a large number of services. The downside of this approach is getting delay notification on status change.

If standard status log is used instead of aggregated status updates, consider putting the directory where the status log is stored on a ramdisk. Ramdisk helps to speed thing up by saving a lot of interrupts and disk thrashing.

Use max_concurrent_checks option to restrict the number of maximum concurrently executing service checks. Nagios is overloaded if the extinfo CGI showing high latency values, say more than 10 seconds, for the majority of service checks.

The overhead needed to process the results of passive service checks is much lower than that of normal active checks. Passive service checks are only really useful if there are some external applications doing some type of monitoring.

Compiled plugin (C/C++) runs more efficient and faster than interpreted script (Perl, etc) plugins. If really want to use Perl plugins, consider compiling them into true executable using perlcc utility which is part of the standard Perl distribution or compiling Nagios with an embedded Perl interpreter.

In order to compile in the embedded Perl interpreter, set the --enable-embedded-perl option in the configuration script before compiling Nagios. In addition, use the --with-perlcache option to enable embedded interpreter caching the compiled Perl scripts for later reuse.

The check_ping plugin used to check host states will performs much faster if break up the checks. This is due to the fact that Nagios judges the status of a host after executing the plugin once.

Hence, it would be much faster to set the max_attempts value to 10 and only send out 1 ICMP packet each time, instead of specifying a max_attempts value of 1 in the host definition and having the check_ping plugin send 10 ICMP packets to the host.

However, the pitfalls of this arrangement will happens when the hosts are slow to respond may be assumed to be down. Another option would be to use a faster plugin check_fping as the host_check_command instead of check_ping.

Do not schedule regular checks of hosts unless absolutely necessary. Set the value to 0 for check_interval directive in the host definition to disable regular checks of a host. Use a longer check interval if really need to have regularly scheduled host checks.

Disable the use_aggressive_host_checking option to speed up host checks. The trade off is that host recoveries can be missed under certain circumstances.

Set the command_check_interval variable to -1 if running a lot of external commands, i.e passive checks in a distributed setup, will cause Nagios to check for external commands as often as possible. This is important because most systems have small pipe buffer sizes (4KB). If Nagios doesn't read the data from the pipe fast enough, applications that write to the external command file (the NSCA daemon) will block and wait until there is enough free space in the pipe to write their data.

System configuration / hardware setup directly affecting how the operating system (and Nagios application) performs. CPU and memory speed are obviously factors that affect system performance, but disk access is biggest bottleneck. Don't store plugins, status log, etc on slow storage medium such as old IDE drives or NFS mounts. Always opt to use UltraSCSI drives or fast IDE drives whenever possible.

Note! Many Linux installations do not attempt to optimize IDE disk access. Use hdparam to change the IDE hard disk access parameters to gain speedy features of the new IDE drives.

Tweaking Windows Server LargeSystemCache

2006-09-17T22:16:00.002+08:00

LargeSystemCache determines whether Windows 2000 Server should maintains a standard size or a large size file system cache, and influences how often the system writes changed pages back to hard disk.

Increasing the size of the file system cache generally improves server performance, but it reduces physical memory space available to applications and services. In addition, writing system data less frequently minimizes use of the kernel disk subsystem, but the changed pages occupy memory that might otherwise be used by applications.

LargeSystemCache is DWORD registry data type that could be located at registry path

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

Setting LargeSystemCache to 1 (system default)

Establishes a large system cache working set that can expand to physical memory, minus 4 MB, if needed. The system allows changed pages to remain in physical memory until the number of available pages drops to approximately 250. This setting is recommended for most computers running Windows 2000 Server as file server on large networks.

Setting LargeSystemCache to 0

Establishes a standard size file system cache of approximately 8 MB. The system allows changed pages to remain in physical memory until the number of available pages drops to approximately 1,000. This setting is recommended for servers running applications that do their own memory caching, such as Microsoft SQL Server, and for applications that perform best with ample memory, such as Internet Information Services web server.

Other than access to registry via regedit.exe and edit directly, alternative method to tweak LargeSystemCache is by

accessing to the Server Optimization tab in Network And Dial-up Connections,
right-click My Network Places,
click Properties,
right-click Local Area Connection,
click Properties,
click File And Printer Sharing For Microsoft Networks,
and then click the Properties button,
to set the LargeSystemCache to 0, select the Maximize Data Throughput For Network Applications option,
to set the LargeSystemCache to 1, select Maximize Data Throughput For File Sharing.

The default setup of Windows 2000 Server initialize LargeSystemCache to 1 which is ideal when running as file server. However, setting LargeSystemCache to 1 can degrade service performance. As such, it is not appropriate when running as application servers such as Web server, SQL server, Exchange server. In this case, reset LargeSystemCache to 0 by selecting the Maximize Data Throughput For Network Applications option in Network And Dial-up Connections.

Compare And Find Best Compression Format

2006-09-17T14:38:00.002+08:00

Compression ratio depends on data and algorithm used for compression. Compression speed counts on CPU power and data compression algorithm in used. Some compression utilities such as 7za, gzip, bzip2, etc, come with options to set level of compression. Setting to higher level of compression will means more time taking to compress and decompress too!

Follow the links below to the comparison of various file compression formats. Find the best compression scheme that suit better for a particular application.

Lzop official site
Rzip official site
7za / 7-Zip / LZMA related article
Maximum Compression benchmark
Practical compressor test benchmark
Ultimate command line compressor benchmark
Linux compression tools benchmark. Find the balance between level of compression ratio and time require to complete the compression process.

Excerpt from the source:

lzop is the fastest tool. It finishes about three times faster than gzip but still compresses data almost as much. It finishes about a hundred times faster than lzma and 7za.

Get even higher compression ratios by combining lzma with tar to increase storage space effectively by 400%.

The data compression tool with the best trade-off between speed and compression ratio is rzip. With compression level 0, rzip finishes about 400% faster than gzip and compacts data 70% more. Rzip default compression level is another top performer too as it can increase effective disk space by 375% but in only about a fifth of the time lzma can take.

Rzip accomplishes this feat by using more working memory. Whereas gzip uses only 32KB of working memory during compression, rzip can use up to 900MB! But that's okay since memory is getting cheaper and cheaper.

7-Zip Better File Archiver Freeware

2006-09-14T13:58:00.002+08:00

7-Zip is a full function file archiver freeware!

7-Zip default to compress files in .7z compression format using LZMA compression algorithm.

LZMA, shorts for Lempel-Ziv-Markov chain-Algorithm, is a data compression algorithm developed on 2001. It uses a dictionary compression scheme similar to LZ77 (such as Gnuzip - better known as gzip in Linux world) but features with
high compression ratio
variable dictionary size up to 4GB
compressing speed at about 1MB/s and decompressing speed at about 10-20MB/s on 2GHz CPU
little memory require for decompressing depends on dictionary size
small code size for decompressing at about 5KB
supporting multi-threading and Intel Pentium 4 HT technology

Besides supporting 7z compression format, 7-Zip too able to compress and decompress some other popular compression formats.

Supported compression file formats:
7Z, ZIP, GZIP, BZIP2 and TAR
Unzip compressed file formats:
7Z, ZIP, GZIP, BZIP2, TAR, RAR, CAB, ISO, ARJ, LZH, CHM, Z, CPIO, RPM, DEB, and NSIS

While the classic Winzip, WinRAR, PowerArchiver, etc discontinue as true freeware, 7-Zip becomes better alternative freeware of file archiver as it is distributed under the GNU LGPL, with exception for the RAR plugin.

Others attractive features of 7-Zip such as:

Supports files size up to 16000000000GB
Unicode file name
Self-extracting capability for 7z format
Integration with Windows Shell
Ability of using any compression, conversion or encryption method
Multilingual interface up to 63 languages at time of writing.
Available in various platforms such as both Windows 32-bit and 64-bit version, Unix, FreeBSD, Redhat, Fedore Core, Debian, Gentoo, Mac OS X, BeOS etc

DisablePagingExecutive Boost Windows Performance

2006-09-14T00:01:00.001+08:00

Tweaking Windows core performance by editing registry key called DisablePagingExecutive only if

plenty of memory installed, e.g. 1 GB RAM or more
most of the memory being unused or idle on most of the time (wasting resource!), and
Windows 2000 and above (Windows XP, Windows 2003) is running.

DisablePagingExecutive is a DWORD data type that could be located at registry path

HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

The initial setup of Windows XP default DisablePagingExecutive value to zero. Setting this value to 1 to enable Windows core to fully utilize the huge memory installed. Tweaking this registry key benefits driver debugging too as all of the code and data are always memory resident. It also improves Windows system core performance by preventing high frequency of disk read in order to get code and data out from hard disk to memory for processing!

Related information:

Search more related info with Google Search engine built-in

Find And Remove Duplicate File

2006-09-13T21:17:00.001+08:00

When the hard disk space going larger and larger, more files are storing into it. Over the time, there might be a lot of duplicate files scatter around the file system.

As bulk of these redundant files are here and there, redundant files mess up file system, decrease system performance, wasting valuable disk spaces, and ineffective file backup. It takes time and could be a really tedious job to find and delete these redundant files when low disk space alarmed!

MD5 checksum could be a good candidate to find duplicate and redundant files! It could be used to precisely identify which files have updated since last backup done by comparing the MD5 checksum of files between source and target of the backup.

MD5 short for Message-Digest algorithm 5, is a widely-used cryptographic hash function with a 128-bit hash value. MD5 has been employed in a wide variety of security applications used to check the integrity of data stream, TCP/IP packets, files, etc.

Related information:

MD5Sums is a tiny Windows command line freeware that able to automatically generate MD5 checksum for all files in a directory except sub directories. Technically, a Windows shell scripts such as VBScripts could be written to programmatic find duplicate files that reside in the file system by calling this tiny freeware via Run method of WshShell object.
MD5 unofficial homepage to find implementations in various programming languages.
MD5 shell scripts to find unique and redundant files in given directory
Search more related info with Google Search engine built-in

Unzip RAR With ExtractNow Freeware

2006-09-12T22:49:00.001+08:00

ExtractNow is a great non-adware freeware used to decompress RAR compression file format!

As its name suggests, ExtractNow is merely an decompressing utility and is not a complete archival software. Nevertheless, this simple free utility is more than enough to satisfy today most decompressing functions. Other than supporting RAR compression file format, ExtractNow also support today majority compression file format such as ZIP, ISO, BIN, IMG, IMA, IMZ, 7Z, ACE, JAR, GZ, LZH, LHA, and SIT!

ExtractNow developer suggest not to bundle DLL that used to enable SIT compression file format support in its installer so as to reduce (installer) file size. Having say that, separate download of DLL is needed if expected to enable SIT support in ExtractNow.

Related information:

ExtractNow official site
Click here to separate download DLL to enable SIT file compression support
Search more related info with Google Search engine built-in

Sharing Big File With File Splitter

2006-09-10T23:36:00.001+08:00

Email a big file of few megabytes as attachment is never a good idea as it will likely to hang up the email server. Because of that, most email servers are likely configured to not relay or process email with non friendly attachment too. If it is really need to email such attachment,

Split the file into pieces of smaller size with file splitter such as File Chopper.
Compress the file to highest possible compression ratio and creating span disk (support by most zip utilities such as WinRar & Power Archiver)
Upload the file to public file server such as upload.com and rapidshare.de that offers file sharing services.
CAUTION! It is better to zip the files with strong encryption before uploading to any public file sharing providers. Zip the files with encryption helps to reduce file size as well as protect sensitive data from the eyes of non expected readers!
Combination of the three method - split the file, compress it with password encryption, and host the split-compressed file to public file server.

File splitter is preferable than span disk feature of zip utilities as file split could be rejoined with Windows built-in command whereas "span disk" require the receiving end to have similar zip program installed.

Related information:

File Chopper is a tiny file splitter program that able to chop a file into arbitrary file size and automatically generate a MS-DOS batch file used to rejoin the pieces of file back to its original file. The batch file is using Windows built in DOS copy command to do the job. For example, typing
copy /b File.1 + File.2 WholeFile.exe
to rejoin split files called File.1 and File.2 back to its original and workable file called WholeFile.exe
Uploading.com only allow unlimited download at certain countries or registered users only. Downloading speed is quite fast as at time of writing.
Rapidshare.de works similar to uploading.com
Using Lycos Mail account. The redesign of Lycos Mail upgraded to allow unlimited attachment size as claimed in its official site, provided not exceeding the default 3GB email storage space allocated to each email account. Although, the recipient's email system might not accepting such emails with huge attachment size. So, use Lycos Mail to send email with unlimited attachment size only to recipient's Lycos Mail email account! Perhaps, this is the Lycos Mail's intention to get more users to attach with Lycos Mail and not the others like Yahoo! Mail or Gmail!
Search more related info with Google Search engine built-in

Using VNC And Redhat Linux

2006-09-10T18:50:00.001+08:00

VNC shorts for Virtual Network Computing which is based on Remote Frame Buffer (RFB) protocol. VNC enable any VNC compatible clients running on any platform to access remotely, in graphical mode, to any VNC compatible server running on any platform!

For example, a VNC client running on Windows XP able to remote access to the Redhat Linux X windows via VNC daemon running on Redhat Linux, or the Redhat Linux VNC client able to access to Windows XP and run the Windows program in Windows XP via the VNC session.

The term daemon is normally refers to Linux/Unix-based server application/process. So as here. And the term "server" is then refers to a Windows-based server application/process.

VNC provides not only GUI remote access but also persistent desktop where the long running program or unfinished editing works could be kept running while VNC session is closed. User could reconnect back later at some other places and straight away continue to work on the incomplete tasks.

However, there is a different in handling convention VNC session between Linux to Windows and Windows to Linux. When access from Linux VNC client to Windows VNC server, the screen seen in Linux VNC client is the same as one see in front of the real physical GUI console. When a Windows VNC client connects to Linux VNC daemon such as VNC Server, the screen seen in Windows VNC client is different from the real physical GUI console. This happens because the Linux X windows use the default :0 display (X server screen number) on startup and the port is not sharable with other sessions. The work around is by using x11vnc or the Redhat bundled Vino as VNC daemon.

Vino allow legacy VNC client access directly to the :0 display. For example, Redhat Enterprise Linux ES 4 comes with vino RPM package. Once installed, the Vino is called Remote Desktop and normally grouped under Preference menu. Its simple GUI configuration make it easier to startup the Vino's VNC daemon!

VNC Server is bundled with all Redhat Linux distribution. Once installed, start the VNC Server by typing vncserver at command prompt. The vncserver command, is actually a shell scripts file, bring up the first VNC Server daemon listening to TCP port 5801 & 5901 by default. To bring up second VNC Server daemon, specify a port number other than the default. For example, type vncserver :2 to bring second daemon listening to TCP port 5802 & 5902. Port number starting from 5801 is meant for Java-enabled web browser connection, while port number starting from 5901 is meant for legacy VNC client connection. Although VNC Server could not directly connecting to :0 display by default as Vino or x11vnc do, this feature could be enabled by using VNC loadable module for the X Window system or upgrade to VNC Server version 4.x.

x11vnc works like Vino but has much more features bundled such as built-in SSL encryption/authentication, file transfer, etc. x11vnc is written in plain C language and uses only standard libraries. So, there is no compatibility and performance issues by using x11vnc as VNC daemon, indeed!

Connecting from VNC client of any platform to Windows VNC server is quite straightforward. Just type the IP address of the Windows VNC server in VNC client will do. However, a combination of IP address and display port is used to connecting VNC client of any platform to Linux VNC daemon. The display port number is taken from the last 2 digits of Linux VNC daemon listening port number (ignore leading zero if any). For example, type http://10.170.46.111:5801 at any Java-enable web browser in order to connect to a Linux VNC daemon that listening to port 5801 or type 10.170.46.8:1 at any legacy VNC client in order to connect to Linux VNC daemon listening to port 5901.

Related information:

x11vnc official site
VNC Server v4.x official site
TightVNC VNC utilities
UltraVNC VNC utilities
Search more related info with Google Search engine built-in

What Happen When Deleting A File

2006-09-10T15:29:00.001+08:00

What happen to a file when deleting it from Windows? The native Windows OS delete function simply remove the file entry (complete path and filename) from directory entries. The file's data content, however, is still remain untouched in the storage area. That is why to copy a file of few hundred megabytes take some minutes while deleting it takes just few seconds.

Disk formatting isn't different. Unless low level format or Zero Fill is performed, an advanced undelete utilities able to recover data from a hard drive formatted with high level or native disk format utilities. With low level format, the entire hard disk is then filled with "zero", hence overwrite any data reside in the hard disk!

Note, it is better to use low format utilities from the respective hard disk manufacturer instead of generic low formatter (such as the BIOS built-in function) to avoid the hard disk unusable later!

Related information:

How to undelete a file from Windows
How to delete a sensitive file securely
SDelete command line utility used to delete sensitive data securely
Sure Delete Window GUI utility used to delete sensitive data securely
Create File - Windows 2000 Resource kit used to generate empty file of arbitrary size up to 4GB (when running on Windows XP)
WipeFree command line utility used to generate dump file to fill up free disk space where the deleted file reside
Search more related info with Google Search engine built-in

Zero Fill Sure Delete Sensitive Data

2006-09-10T12:12:00.002+08:00

Simply delete a file or format a hard disk by conventional way doesn't securely protect sensitive data stored inside the hard disk!

There are chances that other people able to recover or undelete the sensitive data by using simple undelete utilities such as Restoration.

However, there are utilities too that able to anti-undelete data deleted from hard disk! Anti-undelete utilities such as SDelete and Sure Delete will overwrite the sensitive data at least one time (or more than one times for more security in mind) with arbitrary bits or zero bits as Zero Fill does!

SDelete is a command line utility which is easy to use yet secure than Windows built-in del DOS command or Windows native delete function! To make it easy to use,

Click on Start button,
Click on Run menu,
Type cmd in the Open field and click OK to call up Command Prompt window,
Type echo %PATH% at the command prompt and press ENTER to output a list of default program paths separated with semi-colon.
The default program path is used by Windows Run menu and Command Prompt to automatically locate a file or program. For example, the Run menu automatically locate cmd.exe and execute it, after typing cmd followed by pressing ENTER in previous step shown. If the cmd.exe is not reside in default program path, the Run menu will not able locate and execute it automatically.
Put the Sdelete.exe to the any one of the folder path listed in echo %PATH% output, preferable is to use the system folder (e.g. C:\Windows\System32 in a default Windows XP setup),
Add a MS-DOS Command Prompt shortcut with customized option switch to Context Menu (if the shortcut is not there).

After this step, using command line utilities will becomes easier. Just right-click on any folder and click on the MS-DOS Command Prompt shortcut added to Context Menu, the MS-DOS Command Prompt will opens and automatically pointing to the complete folder path of which the folder being right-clicked. Now what? Just type sdelete SensitiveFile.dat to delete a file called SensitiveFile.dat resides in that particular folder - hassle free!

Related information:

SDelete command line utility used to delete sensitive data securely
Sure Delete Window GUI utility used to delete sensitive data securely
Create File is one of Windows 2000 Resource kit (creatfil.exe) used to generate empty file of arbitrary size up to 4GB (when running on Windows XP). Use it to create as many empty file as possible to fill up all the empty space reported by Windows will able to wipe off deleted file data that reside at these free disk space.
WipeFree command line utility used to generate dump file to fill up free disk space where the deleted file reside. It is better than creatfil.exe as it doesn't limited to 4GB file size. Although, its speed is lower than creatfil.exe does.
What happen to a file when deleted from Windows
Undelete files from an emptied Recycled Bin with Restoration
Enable MS-DOS faster change path and auto-complete filename
Search more related info with Google Search engine built-in

Undelete File From Emptied Recycle Bin

2006-09-07T00:08:00.002+08:00

Undelete file utilities able to unerase deleted files even the deleted files no longer in the Recycle Bin!

Thanks to Brian Kato's effort in creating a tiny but great utility which he called it Restoration. It is absolutely free, standalone (no installation required, simply double-click and run), freeware (non-adware), tiny, and a must have software in a USB thumb drive. Depending on the free disk space left on hard disk, those deleted files might able be undeleted by Restoration!

So, don't panic next time if the files being deleted accidentally and emptied from Recycle Bin. SHIFT+DEL or even formatting hard disk also not a problem with Restoration to recover the deleted files!

Download Restoration
What happen when a file deleted from Windows
How to anti-undelete sensitive data
Search more related info with Google Search engine built-in

However, do mind to worry on how to prevent highly sensitive and confidential files from recovery by others!

GNU GDB Core Dump Debugging

2006-09-05T11:49:00.001+08:00

GNU gdb is a must have utility to Linux administrators and programmers! Most Linux package, including Redhat Linux, normally includes gdb as part of the standard distribution. Install the gdb package if it is not there.

GNU gdb is a powerful program debugger and core dump analysis tool. Linux administrators appreciated to have this great utility in tracking down Linux core dump and segmentation fault. Linux programmers rely on it to debug various programming bugs! GNU gdb supports diverse programming languages such as C, C++, Objective-C, Fortran, Java, Pascal, assembly, Modula-2, and Ada.

Analysis Linux segmentation fault or core dump file

To analysis Linux core dump file /home/jason/core.18638 with GNU gdb debugger, run command
gdb /usr/bin/w /home/jason/core.18638
Binary file /usr/bin/w is simply chose. It is because the program which generated this core dump file being unknown in the first place.
The debugger warns that the specified executable file may not match the core dump file. It suggests that the core dump file was generated by "ps ax" command, where an invalid syntax used to run ps command. The gdb output also can't figure out which line of program code trigger the core dump creation, as shown in the last line, "#0 0x4001c9fc in ?? ()", of the screenshot below.
Rerun gdb again with correct binary by typing
gdb /bin/ps core.18638
Now, (as shown in screenshot below), gdb load the appropriate symbols to analysis the core dump file. The last line of gdb output, "#0 0x4001c9fc in stat2proc () from /lib/libproc.so.2.0.7", suggests that the core dump generated while executing the stat2proc function in /lib/libproc.so.2.0.7

Debug an executable C program compiled with debugging information

The C program must be compiled with debugging information that gdb could use. For example, type
gcc -g -o HelloWorld HelloWorld.c
to generate debugging information with -g option of gcc compiler. Gdb will fails to set appropriate breakpoint, as shown in next screenshot, if no debugging information found.

Run the command
gdb HelloWorld
to debug the program called HelloWorld
Create a breakpoint to tell gdb where to stop the program execution in debugger. Gdb accept breakpoint at line number or function of the corresponding C program source code. For example:
- break 679 would instruct gdb to stop at line 679
- break ComputeMean would instruct gdb to stop right before the breakpoint at ComputeMean function
Type run to execute the program inside gdb.

The execution will stop right before the breakdown set in previous step or exit on failure. If it fails before the breakpoint, re-examine where suppose to state the break. Repeat the breakpoint step and rerun.

If no failure found, line number of the corresponding source code where the execution stop will be printed in gdb output. Open the source in program editor, normally Vi editor, to locate that line number to re-code (for debugging) if necessary.

Type
run arg1 arg2 < inputfile > outputfile
if needs to run the program with argument.
Type list to list the whole program source code inside the gdb output.

Type help to get more information on using the gdb command. For example, type help list to get more information on the list command.
After the program execution stop at breakpoint, type
- next or n to move on to next one line of the program source code.
- step or s to step into a function and execute the function line by line. Command next will not step into function but execute the function as a whole. Type finish to exit from the middle of line execution inside the function.
- Type until 967 to execute continuously until line 967 instead of line execution as with next command.
- Type cont to continuously executing until the end, next breakpoint if more than one breakpoint set, or exit on failure
- Press ENTER (means repeat the last executed command) after pressing next, n, step, or s command to make life easier.
Type print variable to view the content of variable.
Use the set variable = 32 command to set the new value 32 to variable.
Use the ptype variable to print the variable type.
Type delete 1 to remove the first breakpoint set.
Type disable 1 to deactivate the first breakpoint instead of removing.
Type enable 1 again to reactivate the first breakpoint.

Related information:

GNU gdb official site
Documentation on using GNU gdb
Diverse programming languages supported by GNU gdb
Search more related info with Google Search engine built-in

Windows Media Player Play All Files

2006-09-04T13:36:00.001+08:00

Windows Media Player to play real media, quicktime, 3gp, mp3, avi, divx, in fact all known multimedia file formats! No more "codec not found to play this file" kind of problem with a super codec pack called Storm Codec!

Windows Media Player that is installed by default should able to play all digital media file formats of today digital world! It cannot play a digital media file simply because it does not find the codec, which is the real engine that decode that multimedia file format. Having say that, a player is just the graphical interface (frontend) of codec that present to user the equalizer, volume control, playing option, viewer windows, etc. It is the codec that really interpreting the multimedia file and not the graphical interface (the "player")!

So, why installing Real Media player, QuickTime player, Winamp, etc? Instead of installing too many multimedia players (the frontend), install only the different codecs will do the job! Disk space should not be a problem to install bulk of these multimedia players with today hard disk capacity. However, fewer such players installed means less messy and burden to Windows registry, lower the risk of DLL conflict, and a better system performance!

Storm Codec is the answer! It is a freeware, non-adware, stable super codec pack that allow Windows Media Player to play most (if not all) known multimedia formats (quicktime, real media, 3gp, mpeg1, mpeg2, mpeg3, mpeg4, wav, xvid, ogg, aac, etc)! The Storm Codec installer, however, install a GNU GPL player called Media Player Classic (MPC). You may bind all the digital media file formats with this player. Alternative, select "None" for not binding with MPC and manually binding digital media file formats to Windows Media Player.

If there is a digital media file format that cannot be played properly, use the bundled program called Gspot to investigate what codec is needed and revisit Storm Codec home page to check for upgrade availability.

Related information:

Storm Codec home page
Storm Codec home page (alternative)
Search more related info with Google Search engine built-in

Vi Editor Quick Reference

2006-09-03T00:49:00.001+08:00

Read this brief introduction of Vi editor cheat sheet for better understanding on the guides follow:

Always use vim (VI Improved editor) instead of vi, as some of the features outlined below are found only with vim.

Another great feature of vim is that, it will always open the file at the line where the cursor stop right before existing from the last file access!

If it has been a habit with vi command name, then make an alias and put it into the login scripts

alias vi='vim'

to retain the simplicity of the command name. For the same reason (of simplicity), the vi command name is used to refer vim, throughout this Vi command cheat sheet!
Bold font used to denote Vi editor's command code.
To execute Vi command code, press ESC to enter command mode.
On start up, Vi editor is in neutral mode. Press ESC follow by i to start editing (insert) mode.
Once complete typing the command code, Vi editor automatically shift to editing mode. Some command codes which initial with ":" (colon), there is a need to press ENTER key to end the command code.
If it is not comfortable with the Vi editor color scheme, turn them off by typing:
- :syntax off - turn off color scheme
- :set nohlsearch - turn off search pattern highlighting
If Vi editor color scheme is a must, but found that some of the color (especially the color of comment lines) is dim and not bright enough for easy reading, tweak the Vi editor by
- :set bg=dark
  or
- :set bg=light
to find the best Vi editor background color for a better colored visual aid and comfortable reading.
Press V to mark the whole line under the cursor, continuous as cursor move. Press v to start highlight as cursor move.
To get "online" help on any of the Vi editor command codes, press :help command code in the editor.

Bulk delete or copy then paste a block of sentences within a file

Move the cursor to the first line of the block of sentences and press mm
Move the cursor to the last line of the block of sentences
Press d'm to delete the block of sentences from current line where the cursor stop to the line where "m" marker initiated in step 1, OR
Press y'm to copy the block of sentences from current line where the cursor stop to the line where "m" marker initiated in step 1, THEN
Move the cursor to a position of file where it is intended to paste the copied block of sentences
Press p to paste the copied block of sentences.

Bulk copy a block of sentences in file A and paste the copied sentences to file B

Move the cursor to the first line of the block of sentences and press mm
Move the cursor to the last line of the block of sentences
Press "by'm to copy the block of sentences from current line where the cursor stop to the line where "m" marker initiated in step 1
Press :e fileB to open another file called fileB for editing
- Use command code :!e fileB instead of :e fileB if there is a need to continue editing fileA after exiting fileB.
Move the cursor to a position of file where it is intended to paste the copied block of sentences
Press "bp to paste the copied block of sentences from fileA to fileB.

Copy portion of text in a line then paste to elsewhere within a file

Move the cursor to the first character of the intended portion of text to be copied and press mm
Move the cursor to the last character of the intended portion of text to be copied
Press y`m to copy the portion of text from the first character where "m" marker initiated in step 1 to the last character where current cursor stop.
Move the cursor to the intended position of the file
Press p to paste the copied portion of text.

To copy portion of text from file A and paste the copied text to file B, use command code "by`m instead of y`m
Read carefully that y'm function differently from y`m as shown. They are different syntax, indeed!

Moving around within the file

Press G to move the cursor to the last line of file
Press 1G or gg to move the cursor to the first line of file
Press nG to move the cursor to the n-th line of file
Press CTRL+b to move the cursor backward in 1 full screen
Press CTRL+f to move the cursor forward in 1 full screen
Press 0 (numeric zero) to move the cursor to the beginning of line
Press $ to move the cursor to the end of line
Press h to move the cursor to the left or press CTRL+h while in editing / inserting mode
Press j to move the cursor down or press CTRL+j while in editing / inserting mode
Press k to move the cursor up or press CTRL+k while in editing / inserting mode
Press l to move the cursor up or press CTRL+l while in editing / inserting mode

Use the arrow key of the keyboard to move up, down, right, or left if it works in your terminal.

Check the current position or line number of the file edited currently

Press :set nu to turn on display line numbering feature
Press :set nonu to turn off line numbering feature
Press CTRL+G to show current file name, current line number, total lines, and percentage of cursor location in the file.

Search a keyword within the file

Press :set ignorecase to search in case insensitive mode
Press :set hlsearch to turn on feature of highlighting matched search term
Place the cursor under the search term exists in the file. Then press * (asterisk) to instruct Vi editor to search for next occurrence of this search term in forward position.
Press /apple to search for "apple" keyword in forward position.
Press ?apple to search for "apple" keyword in backward position.
To search for "Apple" or "apple", apply the regular expression by typing command code /[Aa]pple or ?[Aa]pple

While in searching mode, press N to instruct Vi editor to search in backward position. Press n to instruct Vi editor to search in forward position again.

Replace matched search keyword with new word

Press :s/Color/Colour/gic to replace "Color" with "Colour" in the current line by ignoring case sensitive and ask for confirmation before replacing.
- the g flag indicate to replace all occurrence of the pattern found within the line
- the i flag indicate case insensitive
- the c flag indicate to ask for confirmation before replacing.
Press & while in next line to tell Vi editor repeating the last used :s command (substitution)
Press :1,$s/apple/orange/g or :%s/apple/orange/g to instruct Vi editor to replace all apple found in file to orange
Replace "apple" with "^" in the previous example to tell the Vi editor to insert orange in every beginning of lines in the file.

Blogger Digest :: Notes of regular expression

The . means any single character except newline
The * means zero or more occurrences of any character
The [] means any single character specified inside the bracket
The [^] means any single character not specified inside the bracket
The \< means match at the beginning of the word
The \> means match at the end of the word
The \<ABC\> means match the word "ABC" exactly (and not "deABCfg")
The ^ means match at the beginning of the line
The $ means match at the end of the line
The ^ABC$ means to search for ABC within the line.

Common editing functions

Press A to indicate start of appending at the end of line
Press a to indicate start of appending after the cursor
Press I to indicate start of inserting at the end of line
Press i to indicate start of inserting after the cursor
Press O to insert one blank line before the current line
Press o to insert one blank line after the current line
Press J to join the next line into the end of the current line
Press 3,5J to join the lines of 3rd to 5th into the end of the current line
Press R to indicate start of replacing characters continuously from the current cursor until the start of next command mode (by pressing ESC key)
Press r to replace one single character
Press ~ to toggle character to uppercase or lowercase
Press u to undo one at a time the series of changes made in backward sequence
Press U to undo the latest change made
Press CTRL+R to redo changes made by undo
Press x to delete character to the right of the cursor
Press X to delete character to the left of the cursor
Press dd to delete the whole line where the cursor rest
Press ndd to delete n lines from the line where the cursor rest
Press d$ or D to delete all characters from the cursor to the end of line.
Press N,Md to delete all lines from line N to line M, inclusively.
Press :! top to execute a shell command called "top" (in this example), and return to the edited file when existing from "top" command.
Press : top to execute a shell command called "top" (in this example), and exit to the shell command prompt when existing from "top" command.
Press :!! to repeat the latest executed shell command inside the vi editor
Press CTRL+l to refresh the editing screen
Place the cursor under a filename that exists in the currently edit file, say "stdio.h" that exists in a typical C program source code, then press gf to instruct the Vi editor search (start from the current directory - hence priority of file returned is from current directory) and open the file named "stdio.h"
Place the cursor under a word which is likely part of the Linux man pages, for example "if", then press K will instruct the Vi editor to look for man page of "if" keyword. If there is, the man page is opened right from the Vi editor.
Press :split to split horizontally the currently edited file into two Vi editor windows.
Press :split file2 to split the Vi editor windows horizontally. The upper Vi editor windows access to file2 while the bottom Vi editor windows access to the currently edited file.
While in splitting mode, press CTRL+WW to switch between split Vi editor window. Copy between files made even easier in split Vi editor windows - just copy the block of lines and press CTRL+WW switching to target file then press p to paste the copied lines.

Customize Vi editor environment

Press :set all to print all current VI setting to screen
Press :set nooption to turn off option (e.g. :set nonu to turn off line number printing)
Press :set tabstop=2 to specify each tab equal to 2 spaces
Press :set autoindent to tell Vi perform auto-indention as per previous indented line in the file
Press :set noautoindent to turn off auto-indention
Press :set nu to turn on line number display.
Press :set nohls or :set nohlsearch to turn off feature of highlighting matched search term.
Press :set hls or :set hlsearch to turn on feature of highlighting matched search term.
Press :syntax enable or :syntax on or :syn on to turn on Vi syntax color scheme
Press :syntax off or :syn off to turn off Vi syntax color scheme
If it is very attractive to use Vi editor color scheme, but found that some of the color is dim and not bright enough for easy reading (especially the comment lines), tweak the Vi editor background color and "lighting" by
- :set bg=dark
  or
  :set bg=light
- :colorscheme blue
  or
  :colorscheme murphy (best colored aid)
  or
  Find out what others background color schemes are available by looking at the /usr/share/vim/vim61/colors directory. Find the colors directory from the file system if it is installed at different path, by typing
  
  find / -type d -name colors
  
  The colors directory contains *.vim file such as blue.vim, murphy.vim, peachpuff.vim, shine.vim, etc.

Note! The Vi editor environment setting could either

Place at the bottom of the file content and remarked as comments by the comment identifier. The comment identifier used is depend on the file type. For example, typical C program source code use /* while shell scripts use # as comment identifier. This method is meant to customize Vi editor environment based on file basis rather than apply globally to all files open in Vi editor.

When the file opened in Vi editor, Vi editor will start to interpret the Vi editor environment setup and respond accordingly. Press :set modeline command code if Vi editor is not responding to the setup automatically.

The customization lines seen in a C program source code:

/* vim: set autoindent: */
/* vim: set tabstop=2: */
The customization lines seen in a typical shell scripts:

# vim: set autoindent:
# vim: set tabstop=2:

Create a file called ".vimrc" in home directory. This file will be read by VI editor to customize Vi editor environment for all files opened by Vi editor in the current login session as long as there is no customization embedded in the edited file.

The $HOME/.vimrc file contains one customization setting per line. Hence the $HOME/.vimrc could be seen as

set autoindent
set tabstop=2
set nu
set nohls
syn off

General options to startup VI editor

Type vi + filename to direct Vi editor open the file at the last line of file
Type vi +n filename to direct Vi editor open the file at the n-th line of file
Type vi -r filename to direct Vi editor to edit the last saved version of the file after crash
Type vi -d f1 f2 to open f1 and f2 in Vi editor windows that split vertically. Then, press :diffupdate to highlight the differences found in f1 and f2. Press :set scrollbind will direct Vi editor to automatically refresh and highlight the differences found between f1 and f2. The :set scrollbind is particular useful when one of the files is editing and Vi automatically highlights the latest differences found between these 2 files.

General options to exit VI editor

Press ZZ or :wq or :x to save and exit the edited file
Press :w to save current file without exiting from the edited file.
Press :w f2 to save the edited file to another file named f2 and continue editing the current file. If no save command given to the currently editing file, no changes made will be saved to this current file!
Press :q! to quit the edited file without saving the changes made

Related information:

Search more related info with Google Search engine built-in

Auto Logon In Windows 2000

2006-09-03T00:29:00.002+08:00

Default setup of Windows 2000 and above doesn't recommend auto logon feature. Obviously, it is due to security concerns.

Sometimes there might be just good enough to enable auto logon feature. For example, enable auto boot up and auto logon an information kiosk station that housed inside a securely locked stainless steel cabinet in public area.

Steps to enable auto logon in Windows 2000 and above

Click on Windows Start button,

Click on the Run menu,

Type regedit.exe in Open field and click OK to call up Windows Registry Editor,

Locate to HKey_Local_Machine\Software\Microsoft\Windows NT\CurrentVersion\Winlogon,

Set DefaultUserName to an user account (either local or domain user account) that intended to automatically logon.

Use this guide to create the keys (DefaultUserName, DefaultPassword, DefaultDomainName, AutoAdminLogon) if these keys are not exists,
1. Right click on Winlogon,
2. Select the New,
3. Click on String Value,
4. Enter the name of the key (DefaultUserName, DefaultPassword, DefaultDomainName, or AutoAdminLogon).

Set DefaultPassword to the password of the user account defined in DefaultUserName,

Set DefaultDomainName to a domain that able to authenticate the user account defined in DefaultUserName. If the local user account instead of domain user account is defined in DefaultUserName,
- key in the computer name (Right click on My Computer, click Properties, click on Computer Name to look for Full Computer Name that define the computer name.), OR
- leave it blank if the computer is not current joining to a domain.

Set AutoAdminLogon to 1 to enable auto logon (0 to disable it).

To bypass auto logon (so that able to logon as another user account), hold down the SHIFT key during the boot up or logoff process!

Caution! the password is stored in registry as plain readable text!

Alternative option for Windows 2000 machine that is not joining a domain

Go to Control Panel and double click Users And Passwords,

Select the user account from the list (the account to which intended to automatically logon),

Uncheck check box option Users Must Enter A User Name And Password To Use This Computer and click OK,

Key in the password of the user account selected in previous step,

Click the Advanced tab,

Click to clear the Require Users To Press Ctrl-Alt-Del Before Logging On check box.

Auto Logon In Windows XP

2006-09-02T22:12:00.002+08:00

Default setup of Windows XP and above doesn't recommend auto logon feature. Obviously, it is due to security concerns.

Sometimes there might be just good enough to enable auto logon feature. For example, enable auto boot up and auto logon an interface workstation that housed inside securely protected data center.

Steps to enable auto logon in Windows XP and above

Click on Windows Start button,

Click on the Run menu,

Type regedit.exe in Open field and click OK to call up Windows Registry Editor,

Locate to HKey_Local_Machine\Software\Microsoft\Windows NT\CurrentVersion\Winlogon,

Set DefaultUserName to an user account (either local or domain user account) that intended to automatically logon.

Use this guide to create the keys (DefaultUserName, DefaultPassword, DefaultDomainName, AutoAdminLogon) if these keys are not exists,
1. Right click on Winlogon,
2. Select the New,
3. Click on String Value,
4. Enter the name of the key (DefaultUserName, DefaultPassword, DefaultDomainName, or AutoAdminLogon).

Set DefaultPassword to the password of the user account defined in DefaultUserName,

Set DefaultDomainName to a domain that able to authenticate the user account defined in DefaultUserName. If the local user account instead of domain user account is defined in DefaultUserName,
- key in the computer name (Right click on My Computer, click Properties, click on Computer Name to look for Full Computer Name that define the computer name.), OR
- leave it blank if the computer is not current joining to a domain.

Set AutoAdminLogon to 1 to enable auto logon (0 to disable it).

Click on the Windows Start button,

Click on the Run menu,

Type control userpasswords2 in the Open field and click OK,

Select the user account from the list (the account to which intended to automatically logon),

Uncheck check box option Users Must Enter A User Name And Password To Use This Computer and click OK,

Key in the password of the user account selected in previous step,

Click the Advanced tab,

Click to clear the Require Users To Press Ctrl-Alt-Del Before Logging On check box.

Note, Windows XP Home edition don't allow auto logon with built-in Administrator user account!

DOS Auto Complete Path And Filename

2006-09-01T11:29:00.003+08:00

Enable MS-DOS faster change path and auto-complete filename are the main attractions to use Windows command line utilities!

The fastest and easiest way to change path in MS-DOS or open MS-DOS prompt at indicated path dynamically is by adding tweaked MS-DOS shortcut to Windows context menu. Coupled with MS-DOS's filename auto-completion, it is easier to use various Windows command line utilities such as compiling program source code with command line compilers of C, .Net, Java, etc.

MS-DOS of Windows XP featured with filename auto-completion. Just press TAB key and the MS-DOS will automatically lists the file's name in the current directory. If initial character(s) is typed then only follow by pressing TAB key, it will only lists out those file's name with matching initial characters. MS-DOS of Windows 2000 able to auto complete filename by pressing TAB key too. Although, this feature is not turned on by default!

Turn on Windows 2000 MS-DOS's filename auto-completion feature:

Click the Windows's Start button,
Click the Run menu,
Type regedit.exe in the Open field to call up Windows Registry Editor,
Go to HKEY_CURRENT_USER\Software\Microsoft\Command Processor
Set the value of CompletionChar to 9.
Done. Open MS-DOS, or better known as Command Prompt, to test the result. Now, the MS-DOS should automatically lists the filename each time pressing the TAB key. If initial character(s) is typed then only follow by pressing TAB key, the MS-DOS should automatically lists only file's name that matches with the initial character(s) given. Note, pressing SHIFT+TAB will tell the MS-DOS listing backward.

Add tweaked MS-DOS shortcut to Windows context menu:

Open My Computer or Windows Explorer,
Click the Tools menu,
Select Folder Options,
Click on File Types tab,
Search for "Folder" file type and highlight it,
Click the Advanced button,
Click the New button,
Type a meaningful name, say Open DOS, in the Action field,
Type C:\WINNT\system32\CMD.EXE /k cd %1 in the Application Used To Perform Action field below the Action field,
Click OK button all the way to complete the procedures.
To test the result, right click on any folder in local or network drives (not network folders which are not mapped as network drive). The Windows context menu should has new command shortcut named as Open Dos (the name given in previous step). Click on the Open DOS, the MS-DOS windows (titled as Command Prompt) opened up with the DOS current directory as the folder being right-clicked!

BIOS Beep Code Definition

2006-08-28T16:43:00.002+08:00

When power turn on, most computer system will first executing Power On Self Test (POST). If POST encounters any errors, it will generate beep tones (via the functioning chassis speaker), known as BIOS beep code, to alert the operator.

Different manufacturers might define different BIOS beep code definition. It is better to consult respective manufacturer for precise BIOS beep code definition.

Most of the BIOS beep code of an IBM compatible PC are related to random access memory (RAM) or central processing unit (CPU).

RAM related problems could be due to faulty RAM chip or improper RAM contact with RAM slot.

Disconnect power cord from power supply.
Unplug the RAM module carefully.
Clean the contact with non-static cloth.
Restore the RAM module carefully to the slot firmly.
Power on to perform POST testing again.
If that doesn't work, replace a known good RAM to eliminate RAM possibility.

CPU related problems could be due to a faulty CPU, overheat, or improper CPU contact with CPU slot.

Disconnect power cord from power supply.
Unplug the CPU with care.
Blow away dust found in the CPU heat sink and slot with a blower. Don't blow by mouth to prevent moisture accumulated within the contacts!
Restore CPU to the slot with care.
Power on the computer system for POST testing again.

Ethernet Cable Pin-out Configuration

2006-08-28T08:16:00.002+08:00

It is not a must to have a hub or switch to connect two PCs or servers for networking purpose!

As long as both computer system able to talk on TCP/IP protocol and the network interface cards are functioning, these two computer system could be networked via a crossover Ethernet CAT-5 cable! In fact, crossover cable is also used to link up (stacking) 2 switches or hubs together.

Crossover Ethernet Cable Pin-out Configuration
The maximum length of Ethernet cable should not more than 100 meter to avoid signal loss (unstable network connection).

Pin Number	RJ45 (EIA/TIA 568B Color Code)	RJ45 (EIA/TIA 568A Color Code)	Pin Signal
1	Orange White	Green White	Transmit +
2	Orange	Green	Transmit -
3	Green White	Orange White	Receive +
4	Blue	Blue
5	Blue White	Blue White
6	Green	Orange	Receive -
7	Brown White	Brown White
8	Brown	Brown

Where is pin 1 position at RJ45?
Diagram below showing pin 1 position at RJ45 jack and pin 1 position at RJ45 plug respectively

To network more than two computer systems, a hub or switch is a must. A straight Ethernet cable (not the crossover Ethernet cable) must be used to linked up a computer system to either switch or hub. As the name imply, a straight Ethernet cable has same RJ-45 pin-out configuration at both end of the CAT-5 cable, either by using EIA/TIA-568A standard or EIA/TIA-568B standard.

Percentage Symbol Means Accuracy

2006-08-27T18:08:00.002+08:00

The best indicator to analysis stock performance is percentage! The absolute change in dollars and cents doesn't make sense in analysis stock trading efficiency.

Investor A who bought Google stock at 300 bucks in the morning and realized his gain when Google stock traded at 310 bucks in the afternoon, get 10 bucks or 3.3% as his investment profit.

Speculator B who bought a penny stock at 60 cents in the morning and realized his gain when the penny stock traded at 70 cents in the afternoon, get 10 cents or 16.6% as his investment return!

A wise investor or speculator should always judge his luck or investment efficiency in term of percentage and not the actual monetary gain!

Speculator B should have nothing to complain for the 10 cents as his investment return! Indeed, he should had realized his gain as soon as possible before the stock traded close to 70 cents! An increment over 10% in the same day is quite ridiculous! There are no financial tools in the market that could give such daily return by investor's standard, except for speculator's standard!

Image how much investor A would had made from the penny stock if he turned out to spend his capital of 300 bucks in the same penny stock as speculator B! Investor A perhaps would had sold out his penny stock at 65 cents (8.3% of investment return), given his investment capital and the gain made. Speculator B might out of luck if all the big boys withdraw from the penny stock at 65 cents (and then most likely that penny stock started to trend south)!

Identify Genuine Stainless Steel

2006-08-24T17:18:00.002+08:00

Stainless steel is a ferrous alloy that has higher resistance to oxidation (rust) and corrosion in the present of chromium and nickel.

Chromium forms a passivation layer of chromium(III) oxide (Cr2O3) when exposed to oxygen. The layer is too thin to be visible, shiny, and impervious to water and air to protect the metal beneath. The Cr2O3 reforms quickly when the surface is scratched, a phenomenon called passivation by materials scientists, and is seen in other metals such as aluminium.

Nickel stabilize the austenite structure of iron to prevent stress corrosion cracking. Stress corrosion cracking is a rapid and severe form of stainless steel corrosion that forms when the material is subjected to tensile stress and chloride-rich environment (e.g. sea water) at higher temperature (e.g. 50°C). Nickel is the most expensive element in stainless steel. Nickel is also the material that cause a stainless steel non-magnetic and less brittle at low temperature.

The 400 series of stainless steel, which is usually used for kitchenware are magnetic positive. The 400 series is generally cheapest in price as there is no nickel material in this alloy.

The 300 series stainless steel that is used in chemical plant generally non magnetic, except the cold-rolled stainless steel. The better stainless steel is of grade 304 or 18-8 (18% chromium and 8% nickel) stainless steel. Stainless steel of 18-8 grade offers better corrosion resistance than the 400 series. Most architectural stainless work are done with the 300 series.

Cold-rolled 300 series stainless steel has similar physical composition (18% chromium and 8% nickel) and corrosion resistance of type 304. These are all nominally austenitic alloy (nonmagnetic), but some of the austenite transforms to martensite (magnetic) when the material is deformed, as in cold rolling. This martensite transformation causes the 300-series to be magnetic when cold formed. The cold-rolled material is much harder than annealed material. An annealed 304 stainless steel panel could dent easily.

Selecting Tile For Renovation

2006-08-24T12:15:00.002+08:00

Choosing the right tile for renovation project has never been an easy job. Factors to consider include the grade or the type of tile, color, pattern, surface, cutting, size, price, etc. Combination of tile features could greatly impact the looks and feels of the renovation project!

Homogeneous tile have pigments added into the body before firing at much higher temperature than when producing ceramic tile. Hence, homogeneous tile's surface is much harder, durable, and incredibly suitable for heavy duty usage (such as porch, shopping floor, etc). Once hit with a fallen object, homogeneous tile will not leave a big crack line or a damage surface showing different material or color beneath the surface.

As the whole piece of homogeneous tile is made up of same material, it can be round edged at the sides. Ceramic tile is made of red clay with a thin layer of coloring applied on the surface. Chamfer the edges of ceramic tile reveal the red base below, and PVC strips will be needed to cover the edges of ceramic tile. Homogeneous tile's surface can also be polished to make it reflective and shining like a mirror! A ceramic tile can only be glazed to make it shiny and it's not as long lasting as compare to the polished surface of homogeneous tile.

Porcelain tile is made by the dust pressed method from a composition resulting in a tile that is dense, impervious, fine grained, and smooth. It is available in mat, unglazed, or a high polished finish.

Quarry tile come with glazed or unglazed surface, made by extrusion process from natural clay or shale. Quarry tile is commonly appear in the dark red shades, brown, and gray.

Terrazzo tile is made of marble or granite chip mix with Portland cement or epoxy matrix, molded in various thickness and sizes.

Agglomerate tile is made by mixing graded marble or granite chip of different size with Portland cement, polyester resin or epoxy.

Pegaga Or Centella Asiatica

2006-08-23T17:32:00.002+08:00

Pegaga is a polymorphous, creeping plant, rooting at nodes, with sometimes significant tap root, cylindrical and glabrous stems. Other names of pegaga including Centella asiatica (L.), Hydrocotyle asiatica, gotu kola, Indian pennywort (English), Mandukaparni (India), pegaga (Malaysia), and Ping Da Wan (崩大碗), Di Qien Cao (地錢草), Zhi Xue Cao(积雪草), 雷公根, 蚶殼草, 地堂草, 銅錢草, or 落得打.

Western research studies show that pegaga contains active ingredients such as Triterpenoid glycosides, asiaticoside, Vallerin, Tannins, Alkaloid, Volatile oil, and Pectin. It could act as a relief for fever, bowel complaints, leprosy, rheumatism, ichthyosis, poultice for syphilitic ulcers (Grieve), uterine cancer, wounds, arthritis, stuttering, haemorrhoids, Cellulite (Murray), skin disease, respiratory tract infection, cirrhosis, venous sufficiency, tremors and twitching muscles (Bushell).

Medical benefits

Treat symptoms of nervous breakdown, reduce stress, improve reflexes, and increase mental and physical power.
Reduce high blood pressure.
Slow down ageing process.
Drain out toxins.
Indian use this herb to treat skin inflammations and as a mild diuretic.
Oriental use it to treat emotional disorders such as depression, cure high fever, relieve congestion due to colds and upper respiratory infections.
Positive effect on blood circulatory system by strengthening the veins and capillaries.
Treat phlebitis (inflammation of the veins), leg cramps, swelling of the legs, and "heaviness" or tingling in the legs.
Proven to be particularly useful to people who are inactive or confined to bed due to illness.
Its beneficial effect on circulation may help improve memory and brain function.
Used successfully to promote healing after episiotomy, a surgical incision of the vulva performed to prevent tearing during childbirth. In fact, a study reported in a French medical journal in 1966 revealed that women treated with pegaga after childbirth healed more rapidly than those given standard treatment.

Mascots Of The Beijing 2008 Olympics

2006-08-23T08:26:00.002+08:00

Beijing unveiled five mascots for the 2008 Olympics on 11 Nov 2005, in conjunction of a gala show held in Beijing, to mark the 1,000-day countdown to the opening ceremony of the games. The XXIX Olympiad will take place from 8 Aug 2008 to 24 Aug 2008.

The five mascots are officially called the Five Friendlies, comprises of Beibei (the fish), Jingjing (the panda), Huanhuan (the Olympic flame), Yingying (the Tibetan antelope), and Nini (the swallow). The first syllables from their two-syllable names form a statement "Beijing Huan Ying Ni", which means "Welcome to Beijing".

Furious Water Rafting At Sungai Sedim

2006-08-23T00:48:00.002+08:00

World class challenge in river rafting in Malaysia.

Sungai Sedim at Kulim of Kedah state has a 15KM stretch of fast flowing waters and rapids which are excellent for white water sports activities. Besides the furious rafting, there is also suite for kayaking, camping, jungle trekking, or just just unwind from the hustle and bustle of city life.

Apart from that, there are a few of jungle trekking path that lead to nearby peaks such as Gunung Inas at 1454m ASL, Gunung Bintang Utara at 1835m ASL, Gunung Bintang at 1862m ASL, and Banjaran Bintang at 1699m ASL.

Alternative KLIA Express To KLIA

2006-08-23T00:13:00.002+08:00

KLIA Express is no doubt provides the fastest and easy way from Kuala Lumpur city center to KL International Airport (KLIA)! There is luggage check-in counter where travellers could escape the crowd at KLIA and save time for leisure wandering around KL Sentral or KLIA tax-free trading zone!

Sitting comfortable inside the clean and calm cabin for just about 28 minutes, the speedy train travel non-stop from KL Sentral to KLIA. The price to paid for the convenient, at this time of writing, is Ringgit Malaysia 35 dollars per single trip.

There is also cheaper fare offered by the train operator, with a trade-off that passengers have to stop at intermediate station. Get down from the train at Putrajaya and reenter the next train from Putrajaya again. Just tell the ticket counter that you are looking for KLIA Transit instead of KLIA Express. It only costs a total of RM 15.70 from KL Sentral to KLIA via stopover at Putrajaya! While waiting for next train, probably could consider taking a quick visit to the scenic Putrajaya, which is planned city to serve as new federal government administrative center.

KLIA Express Fare and Schedule

One way non-stop from KL Sentral to KLIA, or vice-verse, at RM 35

Every 15 minutes one train during peak hour, i.e. 0500-0900 & 1600-2200

Every 20 minutes one train during off peak hour, i.e. 0900-1600 & 2200-0000

KLIA Transit Fare and Schedule

Stopping at 3 intermediate stations

Every 30 minutes one train in service

One way from KL Sentral to Putrajaya, or vice-verse, at RM 9.50

One way from Putrajaya to KLIA, or vice-verse, at RM 6.20

Escape To Cameron Highlands

2006-08-22T14:38:00.002+08:00

Thinks of escaping from the hustle and bustle of city life or the hottest summer? Take a trip to Cameron Highlands! One of the few highlands resorts in West Malaysia, filling with cool breeze and freshen ionized air, virgin rain forest, greenly tea plant, beautiful flower and strawberry farm, miscellaneous vegetable farm, attractive dawn and romantic sunset from the peak of Gunung Brinchang, antique English church and smoke house, waterfall, jungle trekking...Another peace of life heaven for natural lovers!

Air-conditioned coach available daily from KL Pudu station, with an intermediate stop at Tapah small town before heading to the Tanah Rata. While at Tapah, don't forget visit to the bamboo basket factory, which had been one of the main source of income for the Tapahan. It has been a sunset industry when the farmers from Cameron Highlands abandoned to use bamboo basket for their vegetables packing. Asam Laksa and fried kuey teow are still the famous food in the town. The lovers restaurant at the Sungai Tapah river bank or the rest house at its opposite hilltop could be nice chit-chat venue too.

Omnibus services, some are air-conditioned, running daily from Tapah town to Cameron Highlands too. Don't worry about the drivers' skill. They all trained to drive you through the curly road from Tapah to Cameron Highlands. The only thing to worry is whether you will vomit in the coach. Before boarding, prepare some soul junks that help to lighten vomit feel!

Omnibus schedule from Tapah to Cameron Highlands:
0800am, 0915am, 1030am, 1115am, 0130pm, 0300pm, 0430pm, 0600pm

Omnibus schedule from Cameron Highlands to Tapah:
0730am, 0800am, 0900am, 1030am, 1130am, 0115pm, 0315pm, 0415pm, 0530pm

Bash Shell Scripts And Bad Interpreter

2006-08-22T08:10:00.002+08:00

Beware! A Linux Bash shell scripts might fails to execute at all after uploaded from a different operating system. For example, from Windows OS to Redhat Linux.

Why? It is due to different encoding format implemented in different OS!

To confirm the shell scripts could run properly, always conduct testing upon finishing transfer. For example, duplicate a copy of the shell scripts transferred, remark all the lines of the shell scripts except the very first line where normally begin as #!/bin/sh (Sha-bang), append one simple line such as echo "test", then save and execute it. If the scripts fails to execute with error messages : Bad interpreter : no such file or directory, it might due to file encoding format!

Most commercial UNIX system default to Bourne shell /bin/sh (hence, called Bourne shell scripts) whereas Linux system default to Bash shell /bin/bash (hence, called Bash shell scripts). A symbolic link /bin/sh pointing to /bin/bash is usually created during Linux setup.

The first line of most UNIX shell scripts is #!/bin/sh. The two characters #!, known as sha-bang, tells the UNIX operating system that this file contains a set of commands to be fed to the command interpreter specified, which is /bin/sh.

This very first line #!/bin/sh can be omitted if only a set of generic system commands are used, or not using internal shell directives at all. Best practice is to include this line anyway.

If the UNIX shell scripts fails to execute with rejected error messages : Bad interpreter : no such file or directory,

Run command ls -la /bin/sh to confirm the specify path of command interpreter (the shell) is correct.

In Linux system, it should be a soft link to /bin/bash. Verify that /bin/bash exists and create the soft link named /bin/sh if the link is not exists.

Run the command ln -s /bin/bash /bin/sh to create a soft link (symbolic link) called /bin/sh pointing to the physical file /bin/bash.

If the path is valid, then
Make a copy of the scripts file.
Next, run command dos2unix YoursScriptsFileName.
Finally, execute chmod 755 YoursScriptsFileName.

If this step works, it means the scripts file encoding format is not compliance to UNIX/Linux format. Chance is there if the file being transfer from other platform like Windows OS.

Running command od YoursScriptsFileName and compare the first line of octal format of the file contents to the octal output of command od BackupScriptsFileName will tell the different.

Amazing Pre-shool Maths Formula

2006-08-21T22:12:00.002+08:00

Feeling dull on the black and white accounting system, worsen by Monday blue effects and a hazy morning? Try this funny maths...reproduce any given 7-digits code (e.g. last seven digits of a cellphone number, ICQ number, etc), after applying that number with a series of simple pre-school calculations:

Enter first 3 digits of the 7-digit code to your normal calculator.
Multiply the number by 80
Add 1 to the previous result
Multiply the result from previous step by 250
Plus the result with the last 4 digits of the number
Plus last 4 digits of number once again to the previous step result
Minus it with 250
Divide it by 2
Bingo! That is the original 7-digits code.

Blood Type Compatibility

2006-08-21T21:55:00.002+08:00

Recipient blood type	Donor blood type must be
AB+	Any human blood type
AB-	O-	A-	B-	AB-
A+	O-	O+	A-	A+
A-	O-	A-
B+	O-	O+	B-	B+
B-	O-	B-
O+	O-	O+
O-	O-

Conclusion of blood type compatibility

AB+ blood type is a selfish type! Recipient of AB+ blood type can receive any blood type donation (must be human blood type, of course!), but itself cannot donate to any blood type except own self!

Blood group AB individual has both A & B antigen on the surface of red blood cell, and his blood serum does not contain any antibodies against either A or B antigen. Hence, an individual with type AB blood can receive blood from any group (AB being preferable), but can only donate blood to another group AB individual.

Blood group A individual has the A antigen on the surface of red blood cell, and his blood serum containing IgM antibodies against the B antigen. Therefore, a group A individual can only receive blood from individual of group A or O (A being preferable), and can donate blood to individuals of group A or AB.

Blood group B individual has the B antigen on the surface of red blood cell, and blood serum containing IgM antibodies against the A antigen. Thus, a group B individual can only receive blood from individuals of groups B or O (B being preferable), and can donate blood to individual of group B or AB.

O- individual is great donor! Individual of O- blood type can donate to any blood type! But O- individuals himself is high risk group! They can only receive blood of O- only!

O+ is slightly less vulnerability than O- individual, considered as second high risk group. Individuals of A- and B- blood type are in this group as well.

Blood group O individual does not has either A or B antigen on the surface of red blood cell, but their blood serum contains IgM antibodies against both A and B antigen. So, a group O individual can only receive blood from a group O individual, but they can donate blood to individuals of any AB, A, B, or O blood group.

Wash Away Oily Dirt

2006-08-21T00:00:00.002+08:00

Give a few drop of lemon juice or white vinegar fluid to the oily dirt and wipe it with a wet cloth. Applying this tips could make the conventional washing method later much easier to eliminate the oily dirt!

Efficient Clothes Washing

2006-08-20T23:35:00.002+08:00

Clothes washing agents used to alkalized the water. Alkalized water made dirt cleaning easier.

Once mixing up dirt clothes with washing agents in barrel of water, the dirt will extracted out within ten minutes. If the clothes is in the water longer than ten minutes, the extraction process reverted as dirt turns alkalized water to become acidic again. The dirt becomes much difficult to wash away from the fiber of clothes in an acidic water.

So, wash the dirt clothes as soon as it is in the water!