In the beginning
Linux has continually developed for almost twenty years and has a somewhat eclectic heritage. It was created by a 21-year-old student, Linus Torvalds, and was released in September 1991. The earliest version, 0.01, came with the declaration that it was a basic alternative to the Unix derivative MINIX.
What is Unix?
An operating system for large-scale computer systems (such as mainframes) created by AT&T at Bell Labs as an operating system which was not tied to one hardware manufacturer’s platform.
With the concept of the GNU licence already established, allowing the open and fair sharing of software under a common licence, Linus shared his code with users of a MINIX internet forum. Within a month the code was returned by the community, tweaked, modified and improved. In October 1991, version 0.02 of Linux was released.
What is MINIX?
Preceding Linux, MINIX was the ‘cult’ Unix derivative; but it was not easily accessed by PC users. It was written in 1987 for educational purposes by university professor Andrew Tanenbaum.
Unlike its Unix ‘patriarch’, Linux was free for anyone to use, adapt and, more importantly, use on the then current PC AT hardware platform. In essence, the growth of the operating system relied on the enthusiasm of the community as well as the desire to access the then new i386 hardware.
Tux, the Linux brand mascot
What is PC AT and i386
PC AT refers to the IBM AT personal computer, released in 1984. Many desktop computers used today are based on the extended form (ATX).
i386 refers to the Intel 386 architecture, introduced in 1985. Although there has been considerable development of processors by Intel and other manufacturers, the Intel chip architecture is still the most common today.
Each revision of Linux supported newer hardware: hard drives, graphics cards and keyboards, for example. By early 1992 the operating system had already gone worldwide and had spread beyond Linus’ initial idea.
How did Linux spread?
The internet is not a post-1995 revolution; before then BBS (bulletin board systems) and email were available to most universities and large ‘connected’ corporations, as well as government organisations and defence establishments. The individuals who worked with Linus on the development of Linux were part of this wider community.
As Linux became established, more free and ‘open source’ code was available for applications, programs, utilities and ‘features’. Commercial vendors joined in the development and distribution of Linux, with companies such as Red Hat joining the fray.
In parallel communities, such as Debian who are the originators of the code supporting Ubuntu, groups worked on standardising code and the distribution of Linux.
What is source code?
When a computer program is created, the original code is called the ‘source code’. This is then subjected to a machine encoding stage (called ‘compilation’) for use on a specific computer system.
By 1996 Linux was already extensively used by many academic communities. It was being used in desktop computing, clustered computing, being tweaked for some handheld devices and used on servers. It was gaining a reputation for reliability, and it was still free.
What is clustered computing?
When many computers are interconnected to share processing power and storage, it is described as ‘clustered computing’. The most common example of this is Google, who have large clustered computing facilities interconnected worldwide to run their search engine and other services.
A steady evolution
Still in the domain of the ‘geek’, Linux was slowly being adopted by corporations and ordinary users alike. This was supported by the inclusion of easy-to-use desktops (with graphical user interfaces). This ensured that those who were non-technical could use the system in a similar way to the popular commercial operating systems.
Therefore the potential non-expert user could access a range of operating systems, where each is based on Linux, each could be directly installed or run from a bootable CD, accessed from a USB flash drive or run as a virtual machine.
What is a virtual machine?
A virtual machine is a software environment designed to emulate (copy) the behaviour of hardware. This allows users to install an operating system within a ‘host’ operating system. Examples of virtual machines include VMware, VirtualBox, QEMU and Microsoft Virtual PC.
Unlike many other operating systems, the same core (known as the ‘kernel’) lies at the heart of all Linux systems. The same kernel can be compiled to work on a range of hardware systems, so you can find Linux on many different devices: from mobile phones to supercomputers. With other operating systems you are likely to find that different versions are needed for servers, desktop computers and mobile phones.
Importantly, unlike most other operating systems, Linux can be installed on a low-specification systems. This is a result of subtle programming and a somewhat ‘geeky’ desire by some to ensure that they can still use their older computers. Because Linux can run well on older hardware, is easily modified and is free, it is very popular in developing countries and in education.
Visit http://www.linux.org/ dist/ list.html and explore the range of Linux ‘distributions’ available. A distribution is a Linux term for a different version of Linux. There are different distributions for the many different worldwide languages.
At the time of writing, the list contains 194 distributions; this does not include unreleased, private distributions nor other projects on the internet.