UNIX

UNIX was originally developed in 1969 by K. Thompson, R. Canaday and D. Ritchie for minicomputers in the Bell Laboratories in the USA owned and run by AT& T. By the mid-1970s, UNIX had been introduced to University of California at Berkeley by Thompson, then widespread into an academic world. Most computer science departments of universities have been used UNIX. UNIX initially became popular in industry because for many years AT& T licensed the system to universities for a nominal fee. The effect of this was that UNIX was carried by recent computer science and engineering graduates to their new places of employment. Rapid commercialization of UNIX followed on from this. This rapid commercialization caused the lack of standards. Many hardware and software vendors developed their own versions.
After UNIX was widespread, it had been used by scientists and engineers. It is because of its scientific and technical orientation. It is less well known with business people. All that, however, is probably about to change. The reason is that with the arrival of very powerful microcomputers using the newer chips such as pentium and pentium-pro chips, UNIX has become a major player in the microcomputer world. The difficulty of learning is also about to change because of the graphical user interface.

This is a multiuser, multitasking operating system that runs on many different computer systems from microcomputer to mainframe, because UNIX is written in C programming language, which is a language designed for system-level programming. UNIX is consisted of a kernel, the file system, the user interface. The kernel is the heart of the operating system. The file system has a hierarchical directory method for organizing files on the disk and the shell.

Advantages and Disadvantages

• Advantages: UNIX is the portable operating system that can be used with many different computers from mainframe to microcomputer. The other operating systems such as DOS, Windows, Mac operating system, and OS/2 cannot be used for other systems. One of many strong features of UNIX is multitasking. UNIX allows users to run multiple programs simultaneously.
  UNIX also shares it among multiple users. UNIX is not restrained by the computer systems such as conventional memory as the DOS and OS/2 systems are. It can accomplish many operations that were formerly performed on minicomputers or mainframes. It is important, because industry can achieve the performance and benefits of large computers from microcomputers by using UNIX.
  Networking is another strong feature of a UNIX operating system. UNIX can be connected through several different kinds of equipment. It can share files among them.

• Disadvantages: Although UNIX can do many things, it can be difficult for novice microcomputer users to understand. This is a reason it has had a limited impact to date. UNIX was a minicomputer operating system used by programmers and computer science professionals some time before the rise of the microcomputer. This means that it has certain qualities making it useful to programmers - many supporting utility programs and documentation, for instance. Some of its features make it difficult for end users.
  Limited application programs are another disadvantage for UNIX. UNIX off-the-shelf programs for microcomputers are limited. However, this situation is going to change, because many software vendors are rewriting DOS and Windows applications for UNIX.
  There is not a standard for UNIX. This may be the biggest problem for the popularity of UNIX. The principal microcomputer versions are the AT& T UNIX System V, the UC Berkeley UNIX, and Xenix developed by Microsoft for a microcomputer version. AIX from IBM, Solaris, and Linux are other variants of UNIX. An application program written for one version of UNIX may not run on other versions.
  There is also not a standard GUI for many UNIXs. There were several attempts to combine the Sun, AT& T, and U.C. Berkeley versions of UNIX to produce a standard graphical user interface. The one was Open Look (Sun/Open Windows) by Sun, AT& T and Berkeley. Another graphical user interface was an OSF/Motif by the Open Software Foundation (OSF). OSF/Motif is now in severe disarray.

Linux

Linux is a great variant of UNIX. It has most of the features and, in some cases, better features of UNIX. Furthermore, it runs on lower end machines - 386- class system or higher with 8MB of memory. It requires only as small as 20MB of hard disk space to install it. It requires a CD-ROM drive. Users can get all these features at only $30 to $50 (Information: http://www.cdrom.com or http://www.morse.net). Users who are not decided to buy can even download Linux free from several ftp sites (e.g., sunsite.unc.edu, tsx-11.mit.edu, ftp.uu.net, and wuarchive.wustl.edu).