Operating Systems

system to have done so. MULTICS examined many new concepts including segmented memory, device independence, hierarchal file system, I/O redirection, a powerful user interface and protection rings. The 1960's also gave rise to the minicomputer, starting with the DEC PDP﷓1. Minicomputers presented the market with an affordable alternative to the large batch systems of that time, but had only a small amount of memory. The early operating system of the minicomputers were Input/Output selectors, and provided an interactive user interface for a single user, and ran only one program at a time. By the 1970's, DEC introduced a new family of minicomputers. The PDP﷓11 series had 3 operating systems available to use on the systems, a simple single user system (RT﷓11), a time sharing system (RSTS) and a real﷓time system (RSX﷓11). RSX﷓11 was the most advanced operating system for the PDP﷓11 series. It supported a powerful command language and file system, memory management and muiltprogramming a number of tasks. Around the same time as DEC were implementing their minicomputers, two researchers, ken Thomspson and Dennis Richie were developing a new operating system for the DEC PDP﷓7. Their aim was to create a new single﷓user operating, and the first version was officially released in 1971. This operating system, called UNIX became very popular and is still used widely today. Fourth Generation Computers (1980﷓1990)By the 1980's, technology had advanced a great deal from the days of the mainframe computers and vacuum tubes. With the introduction of Large Scale Integration circuits (LSI) and silicon chips consisting of thousands of transistors, computers reached a new level. Microcomputers, which were physically much like the minicomputers of the third generation, however they were much cheaper enabling individuals to now use them, not just large company's and universities. These perso...