A Brief History of Unix :: Computer Science

A Brief History of UnixThis document is designed to give people with no previous UNIXexperience some sense of what UNIX is. This document will cover the archives of UNIX and an introduction to UNIX.HISTORY OF UNIX AND CAUSES FOR ITS POPULARITYMost discussions of UNIX begin with the history of UNIX withoutexplaining why the history of UNIX is important to understanding UNIX.The remainder of this document will describe some strengths andweaknesses of UNIX and attempt to explain why UNIX is becomingpopular. All of UNIXs strengths and weaknesses can be todayrelated to the history of its exploitation, hence a discussion ofhistory is very giveful.UNIX was originally developed at Bell Laboratories as a private investigate project by a small group of people starting in 1969. Thisgroup had experience with a number of different in operation(p) systemsenquiry efforts in the 1970s. The goals of the group were to designan operating system to satisfy the following objectivesSimple and elegantW ritten in a high level dustup rather than conference languageAllow re-use of codeTypical vendor operating systems of the time were extremely large andall written in assembly language. UNIX had a relatively small amountof code written in assembly language (this is called the kernel) andthe remaining code for the operating system was written in a highlevel language called C.The group worked primarily in the high level language in developingthe operating system. As this development continued, small changeswere necessary in the kernel and the language to allow the operatingsystem to be completed. Through this evolution the kernel andassociated software were extended until a complete operating systemwas written on top of the kernel in the language C.UNIX APPLICATION PROGRAMMING INTERFACEM both proprietary operating systems have a simplified view ofapplication behavior. The typical application reads some data fromdisk, tape or a terminal and does some processing. produce is producedont o disk, tape, tape, terminal, or printer. The operating systemsgenerally provide easy to use well-implemented facilities to supportthese types of facilities.As applications become more sophisticated they need new features suchas network access, multi-tasking, and interprocess communications. Intraditional operating systems, these features are often hard to use,not well documented, and only callable from assembly language. When aprogram makes use of these features, the program may be much morecomplex and much more difficult to maintain.In UNIX because the C language was written to be utilize to implement anoperating system rather than a traditional input-processing-outputapplication, use of these sophisticated features is quite easily donefrom the C language without writing any assembly language.