08 June 2007

Hijack file in Clearcase

The Hijack command (Team|Hijack) is only available for use with files in snapshot views. Hijacking a file makes the file editable (changes from read-only to a read-write state) without checking the file out. This command lets you work on files when the ClearCase server is not accessible, such as when you are disconnected from the network.

Use ClearCase's Update View wizard (Team|ClearCase Tools|Update View Wizard) to convert the file's ClearCase status from Hijacked to checked out (Reserved checkout or Unreserved checkout) when the server does become available.

To hijack the active file from the Team menu, choose Team|Hijack "".

To use the context menu to hijack one or more files,

  1. Select the file or files in the project pane.

Use the Ctrl key or the Shift key to select more than one file.

  1. Right-click the selection, and choose ClearCase|Hijack Files from the context menu.
  2. Click OK to hijack the files.
  3. Click OK to close the dialog box.

Important: To convert a hijacked file to a checked out file (under ClearCase control), choose Team|ClearCase Tools|Update View to open ClearCase's Start Update dialog box. When you select the Leave Hijacked Files In Place option on the Advanced page of the dialog box, and click OK to update the view, the hijacked files will be treated as checked out files.

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17 May 2007

Apache 2.2 client denied by server configuration

Setting up and starting apache 2.2 went smoothly. The first hiccup occured when a virtual host was added. The site cannot be browsed. The log file says:
client denied by server configuration
Kind of like the problem that I ran into with the 2.0.54 installation
(13)Permission denied: access to /index.php denied

I thought it would be a user/group problem. Apache 2 had a wierd group set by default (#-1). With 2.2 it's not so wierd but a more orthodox 'daemon'. Why it wasn't set to nobody as it used to be with 1.3 is a mystery. Changing it to nobody didn't solve the problem.
Digging deeper, I found the problem in is actually in the root directory configuration section.

In 2.0 it's
Options FollowSymLinks AllowOverride None
In 2.20 it's
Options FollowSymLinks AllowOverride None Order deny,allow Deny from all
The added bit of extra security in 2.20 causes the docroot for the vhost been inaccessible. Just commenting out the access configuration stuff does the trick. A better solution is to add the following with the in the vhost block.
Order deny,allow Deny from all

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13 April 2007

Time Setting in Mediawiki

If you ever wondered about the wrong time shown in the wiki when you look at recent changes, then please take a note of the following.
By default wiki comes with Coordinated Universal Time (UTC) time setting.

Please change your preferences in our wiki by the following procedure if you have not done yet-
Login to your wiki.
Click on my preference at the top right corner.
Click on Date and Time settings.
Under Time Zone, enter 05:30 in the offset text box. (05:30 is the time difference between IST & UTC). This setting is for India. According to your country, you can change this setting.
Click Save.

It will really make some sense while tracking the changes made to any of the wiki pages.
This time preference will show the local time in the following pages-
Recent changes
Related changes
Page history, Image history
User contributions
"This page was last modified" at the bottom of pages
Posted by Picasa

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12 April 2007

PC-BSD: A unix family OS


Now and then a new wind comes along in the ebb and flow of Linux distributions. OK, so I know PC-BSD is not Linux, but it's close enough. It's fair to say without going into technicalities and politics that BSD and Linux are cousins in the operating system world. It is also true that there is some cross-pollination between the two. I'm sure some BSD users have ogled at Linux distributions. Many a Linux user has flirted with the BSDs and or even fantasized about OS X. I know I have. This is exactly why I found PC-BSD attractive. At any rate, let's get to the review.
PC-BSD Vision (bullet points):
The software must be easy to install.
The operating system must be minimalist.
Software must be available, and easily installed.
The system must be dynamic, yet backwards compatible.
You can read the entire PC-BSD Vision here.

The Installation:
The installation is a simple, graphical one. I'’m not sure what toolkit they use for the installation but it looks fairly nice. The installation does just that and not much else. A minimal set of questions is asked. You don'’t even get to select the packages. From the vision, we can see that PC-BSD is targeted at desktop users and the functional and simple installation is appropriate for this purpose. Version 0.7.5 adds the ability to define a custom partitioning scheme.

PC-BSD partition editor

Installer progress

The Desktop:
Since I wasn't given a package list, I had to wait till the installation finished to find out what the default desktop is. After the usual post-installation reboot, the system automatically logged me into a nice KDE 3.4 desktop. Most desktop oriented distributions use KDE so this wasn't a surprise.

I was a bit disappointed with the complete lack of GNOME. More than that, Firefox, OpenOffice, Thunderbird and other popular applications were missing in action. The desktop looks like a standard KDE desktop with a few modifications. There are no unneeded packages or extra bloat. PC-BSD fulfills its goal of being a minimalist distribution (Pt. #2, Vision) quite well.
As you will notice from the screenshot, there is a familiar "My Computer" icon which gives you quick access to hard drives, CD-ROM drives, local network, and settings. In my daily use of PC-BSD, the "My Computer" icon has been very handy. It is also convenient for new users as it functions as a gateway to commonly accessed places. The PC-BSD developer'schoice to place this prominently on the desktop is a good move.

Default Desktop

Package Manager:

While fiddling around with the menu, I ran across an entry for "PC-BSD Program Manager (Remove Programs)" but clicking this only gave me a empty list. What I really wanted to do was to learn how to install programs. I'd heard about FreeBSD's ports system, but I had a feeling that if the system had a remove programs component, an install component was also likely to be present. I headed over to the PC-BSD website which, sure enough, had a list of downloadable packages.

Let me explain the package installation procedure. After you download, unzip, and double click the downloaded PBI file, the PC-BSD installer launches. Security is honored by asking for the root password. A wizard guides the user through installing the package. The user is also asked whether to install desktop or KMenu shortcuts. A slick progress bar is displayed while the actual installation takes place.

I followed this procedure with Firefox and it worked like a charm. Desktop and menu icons were installed as promised. Then I ran the Remove Programs utility again. Now instead of a empty list, it listed Firefox and gave me the option to remove it. I did so just to test the uninstall procedure which worked well. I went ahead and installed some other packages that I required for my day-to-day computing.

In my experimentation with the package manager, it works very well. Any Windows or Mac user will easily follow the procedure. In fact, since all PC-BSD packages use the same installer so adding packages is a more consistent process than Windows.

Another point worth noting is that PC-BSD packages are as self contained as possible. Each package is installed in its own separate directory. For example, Firefox is installed under "/usr/local/MyPrograms/Firefox1.0.4/". This directory contains the executable as well as any libraries it needs. This is a different approach from the majority of distributions that use global libraries.

This method of installing packages has these advantages:
1. Changes to system libraries don't break individual packages. Since all the libraries Firefox needs are in it's own neat directory, any changes to the system libraries doesn't affect Firefox.
2. While this method deviates from tradition, to the user it is transparent. The package installer takes care of all the messy details and the end result is a system that is less likely to break. It's a win-win situation.
The end result of all this work the PC-BSD team has done is that Joe User can download and install software the same way that he does on a Windows machine. And that's a big deal.

Package Creator:

I ran across the third component of the packaging system called the "Package Creator" on the package database. I was expecting it to be a hacker utility to created those pesky PBI packages but it was actually a graphical one. While I didn't create any packages of my own, there is a good tutorial on the subject. Package creation is a complicated by dependencies on every UNIX-like system. The separate libraries solution that I discussed earlier simplifies this problem. This means it's easier for more technically inclined users to create and upload packages and that's always a good thing. I'll have to play out with package creation under PC-BSD a bit more until I give my final verdict.

The Fine Print:

While the project is off to a solid start, there are a few components that need catching up. Like most projects, PC-BSD's documentation lags the development process. At this moment, the only resources users have is the FAQ and the forum. There is a handbook that is planned, but is under construction.

I'm not saying that the developer team is lazy. It's only natural for a system to be developed before documentation gets written for it. Quite to the contrary, PC-BSD's development has been progressing at a furious rate. The lack of formal documentation is made up by a burgeoning community of eager users on the forums. The developers have a good level of interaction with the users on the forums. This collaboration will hopefully iron out some of the smaller issues with PC-BSD.

Speaking of issues, I ran across a few things I'd like to forward to the PC-BSD crew. Since PC-BSD is a desktop operating system, a Windows user should be able to install and use it. At this point, after the installation, there is no "Getting Started" screen or anything of that sort. This could be as simple as implementing Konqueror to the PC-BSD website on the first boot. The user should be shown how to use the system, install and uninstall packages etc. Without a Getting Started document, a less experienced user will get stuck.

Similarly, it would be nice to see a document that lists key differences between Linux and FreeBSD. As someone who runs Linux as well as PC-BSD, I'm aware of the many technical differences pertaining to device names, commands, and runlevels. I've been educated well by the FreeBSD Handbook, but for users who are just starting out with FreeBSD, a less thorough guide is needed.

Another issue is the lack of packages such as Flash, Java, and other such plugins. I understand that inclusion of these packages is legally questionable but it may be something that needs looked into. The developers haven't completely ignored this problem, though. JavaWizardis a PC-BSD package that downloads and configures Java for your system. Hopefully something similar will be implemented for Flash. The presence of JavaWizard is a clear indication that unlike some other developers the PC-BSD team actually use their software. They are aware of the problem and are addressing it. Moreover, you can still use the FreeBSD ports to install some of the above packages but that involves hacking at the command prompt.


It's easy to see that PC-BSD has a lot of potential. Note that PC-BSD is beta software. Version 0.7.5 is stable enough in my experience, but your mileage may vary. When it comes to the basics of installing the operating system and applications, PC-BSD wins hands-down. It is backed up by the solid and slick KDE 3.4. It is a welcome change to the mundane and ordinary. As I was wondering what lies ahead for PC-BSD, I found a Wishlist page that shows a roadmap. With further improvements, PC-BSD will be the next big thing. I recommend you try out PC-BSD today!

Source & Help: www.pcbsd.org

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10 April 2007

Configuring system to run an application on startup

How to configure your system to run an application automatically whenever you boot your system?

First create a shortcut of the application you want to run & put this shortcut to the following location-

D:\Documents and Settings\rtomar\Start Menu\Programs\Startup

Please remember to change “rtomar” with your username. You can put that application directly to this location if you don’t want to put the shortcut.
Following are some typical examples one would like to start automatically whenever he starts system-

Microsoft Office
Web Browser
Your mostly used IDE
Any exe file (In my case, I have an AutoIT script welcoming me on startup)

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09 April 2007

Deadlock Concept in Computing

Deadlock refers to a specific condition when two or more processes are each waiting for another to release a resource, or more than two processes are waiting for resources in a circular chain.

Deadlock is a common problem in multiprocessing where many processes share a specific type of mutually exclusive resource known as a software, or soft, lock. Computers intended for the time-sharing and/or real-time markets are often equipped with a hardware lock (or hard lock) which guarantees exclusive access to processes, forcing serialization.
Deadlocks are particularly troubling because there is no general solution to avoid (soft) deadlocks.

Deadlock concept can be described by the following picture.

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09 March 2007

Package management system

A package management system is a collection of tools to automate the process of installing, upgrading, configuring, and removing software packages from a computer. The term is most commonly used with regards to Unix-like systems, particularly Linux, as these systems rely heavily on it, with thousands of discrete packages on a typical installation being common.

In such a system, software is distributed in packages, usually encapsulated into a single file. As well as the software itself, packages often include other important information, such as the full name, a description of its purpose, the version number, vendor of the software, checksum information, and a list of other packages, known as dependencies, that are required for the software to run properly. This meta-information is typically entered into a local package database.

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