UNIX is the oldest general-purpose operating system. In 1969, K. Thompson and D.M. Ritchie of Bell Labs in the United States developed UNIX based on the smaller and simpler time-sharing operating system MULTICS. At that time, it was implemented on DEC's PDP-7 minicomputer. In 1970 Officially put into operation. For several years, UNIX remained an operating system restricted to AT&T. In 1971, the V1 version written in PDP-11/20 assembly language was developed, including the most basic file system and some simple software. After that, it underwent some improvements.
In 1973, D.M. Ritchie developed the system description language C, and applied the new C to rewrite UNIX originally written in assembly language. This is V5, which makes UNIX modification easier and has the ability to operate on different CPUs. Portability on the platform has become an important feature of UNIX. Since then, UNIX operating systems and applications are almost all written in C language. You only need to have a C compiler on the corresponding platform (convert C language into the corresponding platform machine language translation software), it can be transplanted. C has a traditionally very close relationship with UNIX. In the same year, K.Thompson and D.M.Ritchie submitted the article "The Unix Time Sharing System" at the 4th Operating System Principles Symposium of the American Computer Association. The UNIX system was officially disclosed to the outside world. This article was later published in Commnnication in July 1974. Of ACM Magazine.
In 1975, V6 was launched. After that, Interactioe System Co. (acquired by SUN) became the first reseller of UNIX. UNIX stepped out of Bell Labs and was equipped on PDP-11 machines. It began to spread widely, especially on university campuses. Analyzing the structure of UNIX, correcting errors and making improvements, and developing better-use application software have become the best assignments and graduation project topics for teachers and students majoring in computer science. At the University of California, Berkeley (UCB), some software technicians headed by Willian Joy developed BSD, which was derived from V6 and became a new member of the UNIX family. BSD has developed greatly at Berkeley. Until 1992, the UNIX trademark holder USL (a subsidiary later established by AT&T) sued Berkeley for improper use of the Unix license. Although USL ultimately lost the lawsuit, Berkeley also announced in the same year that it would no longer develop BSD. The ultimate version of BSD is 4.4 BSD, this is something to talk about later. Attached below are schematic diagrams of the respective development processes of the two major UNIX schools AT&T UNIX and BSD. In addition to UCB, Carnegie Mellon University's (CMU) Mach project also has a profound impact on the development of UNIX. Many popular UNIX systems today are related to Mach.
After V6 was launched, V7 was launched in 1978, which included more commands and could support large-scale files. V7 was later ported to VAX machines and was called 32 V in 1981 In 1983, System III was developed, and in 1983, System V, which was suitable for education and easy to maintain, was launched.
In addition to the two main schools, there are also "UNIX-like" operating systems developed by some software and hardware manufacturers on different CPU platforms.
Although these systems have different implementation methods, their functions and operation and management methods are similar to some versions of the main schools. We call them "compatible" UNIX. The following table is a list of compatible UNIX:
Name company hardware platform features
AIX IBM RS6000, POWER PC integrates the characteristics of SVR2 and BSD, unique system management
IRIX SGI PC/workstation latest Version V5.x is based on SVR4
ULTRIX DEC PC has many 4.2BSD and 4.3BSD features
SunOS
(Solaris) SUN 68K, Sparc, X86 based 4.3BSD also has a lot of content from SYSTEM V, NFS and OPEN LOOK GUI standards developed by SUN itself
HP-UX HP X86, developed from HP workstation 4.2BSD
NeXT NeXTstep 68K, X86 is based on Mach core 4.3BSD, has a user-friendly interface and complies with the Openstep standard
Xenix SCO/Microsoft X86 is based on SVR2
SCO UNIX SCO X86 The follow-up product of Xenix, PC UNIX with greater influence
UNICOS Cray Cray supercomputer
Dell UNIX Dell X86 based on SVR4
Minix personal work X86, Mac, Atari and V7 compatible, The originator of LINUX
Interestingly, most of them are not called "UNIX". The main reason is that the UNIX trademark is held by AT & T (later its subsidiary USL). In the spring of 1993, NOVELL will Acquired by USL, the UNIX trademark belongs to NOVELL from then on, and the name "AT&T UNIX" becomes history. In 1994, NOVELL surprisingly gave up the "UNIX" trademark and resold it to the British X/OPEN, which enabled all operating systems that comply with the X/OPEN standard to be called "UNIX". However, NOVELL still retains the copyright of the original UNIX system program code.
Later, it is not mentioned in the book. I will add here that BSD stopped developing after version 4.4 due to a copyright lawsuit with AT&T (later, some development members removed it based on their work in BSD. and AT&T's copyrighted code developed into today's FreeBSD). The lawsuit was finally settled out of court. After that, AT&T faced antitrust charges and sold the UNIX part to SCO. NOVELL sold the source code and their unixware products to SCO, and recently SCO sold their UNIX server part. Sold to Linux manufacturer Caldera...
The two inventors of UNIX won the Nobel Prize in the IT industry - the Turing Prize
for their outstanding contributions in the 1980sp>