Software Release

Types of Software

1. Proprietary – We have to purchase with money
2. Freeware – Freely available on Internet
3. Shareware – Trail and buy version
4. Open source – We can view the source code.

Source code is having 4 different freedom levels

1. View source code
2. Run source code
3. Modify source code
4. Redistribution of source code

Redistribution must be done under GPL (GPL – General Public Licence)

Linux version releases as follows

• 1991 – Linux 0.1
• 1992 – 0.2
• 1993 – 0.3
• 1994 – 1.0
• 1996 – 2.0

For RHEL 5.1, the kernel version is 2.6.18.EL and the recent released is 2.6.29.EL

Distributions of Linux

1. Slake ware
2. Redhat – RHEL (Supported) and Fedora(Un supported)
3. Suse
4. Ubuntu
5. Mandrake
6. Debain
7. Knoppix


Recommendations

If you don't know what you're doing, don't choose distributions that require a lot of legwork to configure basic services or install extra software. If you are new to GNU/Linux and want a great desktop experience, I recommend trying these distros (listed in no specific order):

•   Linspire
•   Xandros
•  SUSE Linux
•  Mandriva

All of these distros will cost you something -- usually under US $100. A lot of experienced GNU/Linux enthusiasts will recommend non-commercial distributions like Ubuntu, Fedora Core, or Debian. These are good distros and are available free of charge, but require that you add proprietary video drivers and Web browser plugins by hand, and don't have the same kind of automatic hardware management that the four distros I listed above have. That means that you could end up rather frustrated by your GNU/Linux experience. Also stay away from the open source edition of SUSE Linux -- that is also missing many of the proprietary extras that you're used to in Windows or OS X (the commercial version of SUSE does have plugins for Java, Flash, and PDF). It's not tough to add them if you follow this guide, but many people are not prepared to get that technical with their software.

If you're looking for a distro that is more suited to server use, try these:

• Red Hat Enterprise Linux
• SUSE Linux Enterprise Server
• Mandriva Corporate Server

Again, people will argue that other distros or Unix-like OSes are better, but the above-mentioned distributions are easy to install, configure, and manage, and come with extensive documentation and commercial support. You will have a much easier time with them, and you're better off going with one of these if you're new to GNU/Linux or Unix-like operating systems in general. You can make virtually any GNU/Linux distribution into a server of any kind; it's just a matter of how much work you have to do to prepare and maintain it. If you don't want to do a lot of work, choose one of the above distros.

Non-commercial desktop distributions of note include:

• Ubuntu
• SUSE Linux OSS
• Fedora Core

If you would prefer more of a challenge, as either a server or a desktop OS, try these distros:

• Gentoo
• Debian
• Slackware
• Arch

Lastly, if you would like to see what a GNU/Linux desktop can look like, you can download Knoppix, a distro that runs entirely from a CD. You write the ISO file to a blank CD-R disc, then restart your computer with the disc in the CD drive. You'll run a whole distribution right from the CD. When you're done playing around, just select the Shutdown menu option, remove the CD from the drive, and restart -- nothing will be written to your hard drive.


Features of Linux
1. Multi user and Multi tasking
2. Clone of UNIX
3. Secured
4. Portable