UNIX (Uniplexed Information and Computing System) is the first set of operating system developed by the C language, the use of simplified reduced kernel with time-sharing (Time Sharing), interactive support multiplexing (Multi-Tasking) moreusers (Multi-User), and multi-program (Multi-Programming) function, widely used on the server, the workstation Sun's SunOS, the PC version of Microsoft's XENIX, Sun's Solarisand shareware versions of Unix such as Linux, FreeBSD, and so on.IBM's AIX, Sun's Solaris, HP's HP-UX, or Linux, etc., are from 1969, AT & T Bell Laboratories (Bell Labs) developed Unix. Recalling the history of Unix, MULTICS (MULTiplexed Information and Computing Service) program is an important key. At that time, most of the computers are using batch (Batch Processing): The concept of batch processing like clothes (Jobs) accumulated to a certain number of laundry, and thrown into the washing machine (CPU) processing only, usually washing machine (CPU) is idle. In order to enhance the performance of the CPU, AT & T, GE and MIT plan developed in cooperation MULTICS operating system. MIT design CTSS (Compatible Time-Sharing System) has been quite successful so MULTICS to CTSS a foundation, build large computer in GE's GE-645. Bell Labs and AT & T both belong to a company that was still in the late 1960s to participate in this plan, Unix father of Ken Thompson is Christine Tue their, by California, Berkeley change to Bell Labs, a MULTICS research team. But the MULTICS development progress is slow, but still have not seen progress over a two-year pre-period, so that in February 1969, Bell Labs decided to withdraw, but the MULTICS still continued development. Honeywell acquired GE's computer division in 1972, MULTICS enter the commercial market, in MULTICS relative prevalence of the 80s, about 75 to 100 millions of dollars worth of large computer use MULTICS.1977 MIT to exit the MULTICS of development, after the mid-1980s, Honeywell Bull sold the computer business, however, the development of MULTICS also 1988 program to a full stop. Ken Thompson in MULTICS, written for the GE-645 (Space Travel), known as the space travel game program, when Bell Labs to exit the MULTICS, Ken Thompson intend to find a machine to transplant in the past this game, so they and Dennis Ritchie toBell Labs to apply for a DEC-10 to create a time-sharing system, the application was not passed.Finally, they used a Pat abandoned in the the next Digital the PDP-7 (1964, when DEC production of mini-computer), Ken Thompson on technical experience in the MULTICS-tree (tree-structured) file system, the command interpreter(Command Interpreter) and access control peripherals - is based on a new set of operating systems have been written for this out-of-date computer. Limited by the machine's performance, PDP-7 only supports two users, it can not be called multi-user (Multi-User). Brian W. Kernighan time and worked with Ken Thompson will play MUITICS that the word itself, playfully joked that their system is actually UNiplexed Information and Computing System is abbreviated as UNICS, whichever is later homonym, called Unix. Because of the limited computing power of the PDP-7, also unlikely to provide parallel processing services to apply again, so Ken Thompson and Dennis Ritchie, please purchase a PDP-11/20 research in the name of the word processing system. PDP-11/20 disk slower than host a full three months before shipped to laboratories, idle time waiting for the disk, Ken Thompson PDP-11 assembly language rewrite the entire Unix kernel and the basic command .Bell Labs Patent Office is looking for a system as a tool for handling files, word processing system developed by Ken Thompson, of Bell Labs, exactly in line with demand, the Bell Labs Patent Office became the first commercial Unix users. So in November 1971, Unix team finally Unix version 1 finalize the instruction manual, the manual is marked for the First Edition, the version number of the documentation development by Bell Labs Unix version are simultaneously published benchmarks. Later, many versions of Unix, I do not want to go. November 1973 Unix V4 important re-written in C language, some small modifications to the source code, you can perform different hardware architecture above. Therefore, this prompted many commercial software companies and academic institutions to accelerate the development of Unix to become a milestone in the Portable Operating System. In this case since 1974, AT & T had to Unix source code available to academic institutions, better stability and efficiency in the implementation of the Unix and adding more features.1975 Unix V6 first use outside of Bell Labs, and to promote the development of California at Berkeley in 1978 1 BSD (1st Berkeley Software Distribution) Unix version, open the branch BSD family of Unix. 1979 Unix V7 is a the unprecedented complete operating system, to be ported to the VAX, called 32V.Due to its compact size, such as Illinois, Harvard, Berkeley and other results is far-reaching to 32V, the Bill Joy and Ozalp Baboglu, in Berkeley-based, virtual memory, demand paging and paging replacementPost 3 BSD Unix, because it has a large memory management mechanism, thereby gaining the support of the U.S. Department of Defense Advanced Institute for Defense Studies (DARPA). The same period, AT & T established the USG (Unix Support Group), gave birth to the Unix market goods, the first edition of the publication is the System III, again is System IV. From the Unix version of the BSD and AT & T compete with each other, and thus divided into two mainstream System IV and 4.x BSD. However, AT & T to court to sue the BSD source code plagiarism AT & T and end of acclaimed BSD systems, due to anti-AT & T drag Las method is broken down into several subsidiaries, but to accelerate the Unix products for the market speed. However, due to AT & T for Unix improvement in commercial applications, modify the spread of degrees of freedom is limited, making this a new concept of the importance of the Open Source world focus.1984 Richard M. Stallman founded GNU (the GNU is Not Unix) plans, developed a set of upward-compatible with Unix, called the GNU free software system, and the Free Software Foundation (Free Software Foundation was established in 1985; FSF), research and developmentmany free software available for use by the general public, also brings a solid foundation of future surging Linux put down roots.