The Warm Up
Next day Eva came to office and met Mike who had promised to start Linux training from next day onwards. Mike was also in time in office and Eva was also eager to start. Mike said, “After you left for home, I was thinking of installing one Linux machine for you. Then later I thought that I should guide you step by step. Before we start our journey next, I think I should introduce you to different flavors of Linux.”.
Mike started telling about different Linux flavours. “Some of the famous distributions of Linux are: Red Hat, Fedora, CentOS, Debian, Ubuntu and SuSE. Each of these have different versions. Some are paid ones and some free.”
Eva asked, “You had told me that Linux was free and open source, Isn’t that so?”
Mike replied, “Yes. But the point is that companies spend lots of money on development of products which they provide for free. To keep the business running, money has to come from somewhere. For that purpose different approaches are adopted by companies behind the softwares. These approaches include subscription licenses, support services, premium products and so on.
One of the approches is to make different versions of same software. One with all the basic features and it’s distributed free. The paid ones are often called premium versions. The difference between the two could be in terms of list of features. Most of the users who use the software, normally don’t require extra features. The extra features are usually required by companies of various sizes. The premium versions of products usually come with support subscriptions.
Another approach is to keep only one version of software and sell the support services and help the clients installing, upgrading and maintaining the softwares.
Yet another approach is to sell related software products which could be considered as advanced software functions. This is achieved in the form of extensions often called plugins and modules.
The benefits of providing the product free to the community are numerous. More the eyes watching the software, more is the ruggedness achieved in terms of bugs removal as the time passes.
Let me now introduce you to some of the famous Linux distributions also called distros.”
The Red Hat Linux distribution was created by Marc Ewing in 1994. Red Hat, Inc., the company behind Red Hat which was founded in 1993 is well known for it’s enterprise operating system Red Hat Enterprise Linux(RHEL). The softwares installed in RHEL have extension .rpm which stands for RedHat Package Manager(rpm). That’s precisely the reason that we call RHEL an rpm based distro. RHEL aims for production servers used in enterprises of various sizes. Hence, more attention is paid to stability and security than latest versions of different softwares used in RHEL.”, Informed Mike.
Eva then asked, “Does that mean that Red Hat also comes with different operating system versions?”
“Yes”, said Mike. “Red Hat not only spend money in further reasearch and development, but backs up several free famous distributions like Fedora. Let’s proceed further.
The Fedora Linux is also rpm based distibution. It is a project which is supported by community and sponsored by The Red Hat Inc. The main target of Fedora Project is to contribute to rapid development of new softwares using open processes. New softwares which are included in Fedora project may later on be included in RHEL. Fedora usually has latest versions of softwares in use and community using is ever increasing. Since, rapidity is the aim, so different versions of Fedora Linux come very fast. That leads to life cycle of Fedora being short and usually it’s not preferred for production use. Fedora also works on several side projects of RHEL which require research and development.
The CentOS Linux is taken from (C)ommunity (E)nterprise (O)perating (S)ystem founded in 2014. For businesses and individuals who can’t afford or don’t want to bear the subscription license costs of RHEL and can’t stand with Fedora’s relatively short life cycles prefer CentOS. CentOS goes in line with RHEL and is supported by community. The target of CentOS is to provide free, community supported and enterprise grade operating system. Functionally CentOS is very much compatible with RHEL which is it’s upstream source. CentOS hence is also rpm based distro and goes independent from RHEL.
The Debian Linux is composed of purely free software. This project was released first as 0.01 version in 1993. Debian also carries the tag of the robust and rock solid operating system. Apart from servers, the Debian and the distros based on it have desktop versions as well which have captured market share of operating systems for personal computers and laptops. Debian Linux has all the softwares installed with the extension of .deb and hence it’s also called deb based distro.
The Ubuntu Linux is based on Debian architecture. It’s widely used on personal computers as well as on servers. Ubuntu gets it’s commercial support from Canonical Ltd., founded by Mark Shuttleworth. The term Ubuntu roughly means Humanity To Others. The operating system has gained immense popularity as a server as well as a desktop. Being based on Debian, Ubuntu is also deb based distro.
The SuSE Linux is open-source Germany based software company which was founded in 1992. The company develops and sells Linux based products to businesses. SuSE is S.u.S.E (S)oftware-(u)nd (S)ystem-(E)ntwicklung i.e Software and Systems Development. SuSE is the company which took Linux to the market for the first time ever in history for enterprises. The community version of SuSE linux is called OpenSUSE project which is sponsored by SuSE. The enterprise product is named as SuSE Linux Enterprise Server(SLES). This is also rpm based linux distro.
Operating System Life Cycle
Eva asked, “What does the term Life Cycle mean for operating system?”
Mike answered, “Life cycle is a generic term used in context of the operating system. It means the time from planning, creating, testing and deploying of the operating system to stopping the support for it. For instance, the operating systems come with several bugs in first place after the first release. Later on these bugs are discovered and reported. These bugs are then corrected and software patches are rolled out for the relevant operating systems. Eventually a time comes when patching up the operating system alone is not sufficient. Also, newer softwares which are developed independently, may not work on older operating systems or could render the operating system unstable. That is the time when new operating system is created with all the previous bugs fixed and new features and softwares included. This time from the date of starting of releasing of new operating system version to the date of stopping providing the support is called the life cycle of operating system.
The approximate dates of start and end of operating systems life cycle are planned and declared in advance. The information is available on websites of the companies behind the operating systems.
The advance knowledge of life cycle or sometimes said as release cycle is important so that businesses can plan the migration of servers to latest versions without taking the business down.
Does that clarify your doubts?”
“Much appreciated.”, said Eva, “How much are the usual life cycles of the Linux distros you just told about??”
“RHEL has provided 10 years of life cycle for it’s versions 5, 6 and 7. And RHEL 4 was given 7 years of life cycle. Same goes for CentOS. Debian and Ubuntu provide 5 years life cycle. Suse Linux Enterprise Server has 10 years life cycle for it’s latest versions.”
Linux distros come in various flavors and are supported by different companies for different reasons.
Red Hat: Backed by Red Hat Inc., Red Hat Enterprise Linux is rpm based distro with 10 years life cycle.
Fedora: RPM based distro making latest softwares available. Has Has short life cycle of about 13 months. Released every six months.
CentOS: Free RHEL community edition emphasing on stability and security with 10 years release life cycle making it suitable for enterprises equally well.
Debian: Deb based rock solid distro suitable for desktops and servers with life cycle of 5 years.
Ubuntu: Most famous in clouds, Debian based distro with life cycle of 5 years. Well suited for desktops and servers.
SuSE: RPM based distro available as enterprise product named SLES(SuSE Linux Enterprise Server) and as OpenSUSE which is community based.