UNIX

Unix (officially registered as UNIX®) is a portable, multitasking, multiuser operating system; developed in 1969 by a group of AT&T Bell Laboratories employees.

The system, along with all rights, were sold by AT&T to Novell, Inc. Novell, Inc. subsequently sold the software to the Santa Cruz Operation in 1995, which in turn resold it to Caldera Software in 2001, a company which later became the SCO group. However, Novell always argued that it only sold the rights to use the software, but retained the copyright to "UNIX®". In 2010, and after a long legal battle, it has once again become the property of Novell.

Only operating systems that are fully compliant and certified to the Single UNIX Specification can be referred to as "UNIX®" (Others are called "Unix-like" or "Unix-like"). Sometimes the term "Traditional Unix" to refer to Unix or to an operating system that has the characteristics of UNIX Version 7 or UNIX System V or unix version 6.

History

In the late 1960s the Massachusetts Institute of Technology, AT&T Bell Laboratories, and General Electric were working on an experimental operating system called Multics (Multiplexed Information and Computing Service), developed to run on a mainframe computer. (mainframe) model GE-645. The goal of the project was to develop a large interactive operating system that featured many innovations, including improvements in security policies. The project managed to give birth to production versions, but the first versions had poor performance. AT&T's Bell Laboratories decided to disassociate themselves and devote their resources to other projects.

One of the Bell Labs programmers, Ken Thompson, went on to work on the GE-645 computer and wrote a game called Space Travel. However, he found that the game was slow on the General Electric machine and really expensive, something like US$75 per game.

So Thompson rewrote the program, with the help of Dennis Ritchie, in assembly language to run on a DEC PDP-7 computer. This experience, along with the work he did for the Multics project, led Thompson to initiate the creation of a new operating system for the DEC PDP-7. Thompson and Ritchie led a group of programmers, including Rudd Canaday, in the Bell Labs, to develop both the file system and the multitasking operating system itself. To this they added a shell (or shell) and a small set of programs. The project was baptized UNICS, an acronym for Uniplexed Information and Computing System, since it only provided services to two users (according to Andrew Tanenbaum, it was only one user). The authorship of this acronym is attributed to Brian Kernighan, since he was a Multics hack. Given the popularity of a play on words that considered UNICS a castrated MULTICS system (since eunuchs, in English, is a homophone of UNICS), the name was changed to UNIX, giving rise to the legacy that survives to this day.

Until then, there had been no financial support from Bell Laboratories, but that changed when the Computer Science Research Group decided to use UNIX on a machine superior to the PDP-7. Thompson and Ritchie were successful in fulfilling the request to add tools that would enable word processing to UNIX on a PDP-11/20 machine, and as a result obtained financial support from Bell Laboratories. This was how for the first time, in 1970, the UNIX operating system running on a PDP-11/20 was officially discussed. It included a program to format texts (runoff) and a text editor. Both the operating system and the programs were written in the PDP-11/20 assembly language. This "word processing system" Initial, made up of the operating system as well as runoff and the text editor, it was used at Bell Laboratories to process the patent applications they received. Soon, runoff was enhanced into troff, the first desktop publishing program that allowed typesetting. On November 3, 1971, Thomson and Ritchie published a UNIX Programming Manual (original title in English: "UNIX Programmer's Manual").

In 1972 the decision was made to write UNIX again, but this time in the C programming language. This change meant that UNIX could be easily modified to work on other computers (in this way, it became portable) and so other variations could be developed by other programmers. Now, the code was more concise and compact, which translated into an increase in the speed of UNIX development. AT&T made UNIX available to universities and companies, also to the United States government, through licenses. One of these licenses was granted to the Department of Computing at the University of California, Berkeley. In 1975 this institution developed and published its own surrogate for UNIX, known as the Berkeley Software Distribution (BSD)., which became strong competition for AT&T's UNIX family.

In the meantime, AT&T created a business division called Unix Systems Laboratories for commercial exploitation of the operating system. Development continued, with the delivery of versions 4, 5 and 6 in the course of 1975. These versions included the pipes or pipes, which allowed development to be given a modular orientation with respect to the code base, managing to further increase the speed of development. As early as 1978, about 600 or more machines were running some of the various incarnations of UNIX.

Version 7, the last widely distributed version of the original UNIX, entered circulation in 1979. Versions 8, 9, and 10 were developed during the 1980s, but their circulation was limited to a few universities, even though the reports describing the new work were published. The results of this research served as the basis for the creation of Plan 9 from Bell Labs, a new portable and distributed operating system, designed to be the successor to UNIX under investigation by Bell Laboratories.

AT&T then began development of UNIX System III, based on version 7, as a variant of commercial dye and thus sold the product directly. The first version of System III was released in 1981. Despite this, the Western Electric subsidiary company continued to sell older versions of Unix based on the various versions up to version 7. To end the confusion with all the divergent versions, AT&T decided to combine several versions developed at different universities and companies, giving rise to Unix System V Release 1 in 1983. This version introduced features such as the Vi editor and the curses library., developed by Berkeley Software Distribution at the University of California, Berkeley. It also had compatibility with the VAX machines of the DEC company.

In around 1991, a computer science student at the University of Helsinki named Linus Torvalds developed a kernel for Intel x86 architecture computers that emulated many of the functionality of UNIX and released it as open source in 1991., under the name of Linux. In 1992, the GNU Project began using the Linux kernel with its programs.

In 1993, the Novell company acquired AT&T's Unix Systems Laboratories division along with its intellectual property. This occurred at a sensitive time as Unix Systems Laboratories was fighting a lawsuit in the courts against BSD for copyright infringement, disclosure of secrets and trademark violation.

Although BSD won the lawsuit, Novell discovered that much of the BSD code was illegally copied into UNIX System V. In reality, Novell's intellectual property was limited to a few source files. an out-of-court settlement the terms of which remain secret at Novell's request.

In late 1993, Novell sold its commercial UNIX division(i.e., the former Unix Systems Laboratories) to Santa Cruz Operation (SCO), apparently retaining some intellectual property rights to the product. software. Xinuos (formerly UnXis) continues to commercialize System V in its UnixWare product after acquiring SCO in April 2011.

Most Significant UNIX Families

• AT strangerT: The family that originated in the UNIX of AT fakeT. Considered the "pura" and original UNIX family. Its most significant operating systems are UNIX System III and UNIX System V.
• BSD: Family originated by the UNIX license to Berkely. BSD was rewritten not to incorporate intellectual property originating from AT fakeT in version 4. The first implementation of the TCP/IP protocols that gave rise to the Internet are the stack (stack) TCP/IP BSD.
• AIX: This family arises from the licensing of UNIX System III to IBM.
• Xenix: Family derived from the acquisition of the original rights of AT fakeT first by Microsoft and sold them to SCO.
• GNU: In 1983, Richard Stallman announced the GNU Project, an ambitious effort to create a system similar to Unix, which could be distributed freely. The software developed by this project - for example, GNU Emacs and GCC - have also been a fundamental part of other UNIX systems.
• Linux: In 1991, when Linus Torvalds began to propose core Linux and joining partners, the GNU tools were the perfect choice. By combining both elements, they formed the basis of the operating system (based on POSIX), which is now known as GNU/Linux. The kernel-based distributions, the GNU software and other aggregates among which Slackware Linux, Red Hat Linux and Debian GNU/Linux have become popular both among computer fans and the business world. Note that Linux has an independent origin, so it is considered a 'clinical' of UNIX and not a UNIX in the historical sense.

The interrelationships between these families are as follows, roughly in chronological order:

• The BSD family emerges from the original AT fakeT UNIX license.
• Xenix also arises by licensing the original UNIX of AT fakeT, although it was not owned by SCO.
• AIX arises by licensing UNIX System III, but also incorporates BSD intellectual property.
• The original AT fakeT family illegally incorporates BSD intellectual property into UNIX System III r3.
• The AIX family again incorporates intellectual property of the AT fakeT family, this time coming from UNIX System V.
• Linux incorporates BSD intellectual property, thanks to its release with an open source license called Open-source BSD.
• According to SCO Group, Linux incorporates intellectual property from AIX thanks to the collaboration of IBM in version 2.4. It is not yet shown and there is a judicial process: SCO Deputies on Linux.

The brand

UNIX® is a registered trademark of Novell, after a dispute with The Open Group in the United States and other countries. This mark can only be applied to operating systems that conform to the "Single Unix Specification" of this organization and have paid the established royalties.

In practice, the term UNIX is used in its family sense. It also applies to POSIX-based multi-user systems (such as GNU/Linux, Mac OS X [which, in its version 10.5 has already achieved UNIX certification], FreeBSD, NetBSD, OpenBSD), which do not seek UNIX certification by be expensive for products intended for the final consumer or that are freely distributed on the Internet. In these cases, the term is often written as "UN*X", "UNIX*", "*NIX", or "*N? X". To refer to them (both Unix and Unix/POSIX-based systems) we also use "Unixes", but "Unices" (which treats the word Unix as a third declension Latin name) is also popular.

Major implementations

Throughout history, a multitude of commercial UNIX implementations have arisen. However, a reduced set of products has consolidated the market and prevails thanks to a continuous development effort by their manufacturers. The most important are:

• Sun Microsystems Solaris. One of the most widespread Unix operating systems in the business environment and known for its great stability. Part of Solaris' source code has been released with open source license (OpenSolaris).
• AIX from IBM. IBM's "owner" UNIX fulfilled 30 years of life in 2016 and continues in full development, with a perceptible mainframe heritage in fields such as virtualization or RAS of services, inherited from its "older brothers".
• Hewlett-Packard's HP-UX. This operating system was also linked to the departmental computers of this manufacturer. It is also a stable operating system that continues to develop.
• macOS. This is a complete UNIX, approved by The Open Group. Its marked difference is that it has a proprietary graphical interface called Aqua, and is mainly developed in Objective-C instead of C or C++.

There are operating systems based on the Linux kernel, and the GNU suite of applications (also called GNU/Linux), among the most used we find:

• Red Hat Enterprise Linux. Which Red Hat manufacturer is known for its wide range of solutions and inputs to free software development. It supports the Fedora project that benefits and derives from it compatible distributions such as Oracle Enterprise Linux and CentOS, also distributions like Mandriva Linux, was based on one of its first versions.
• Novell's Linux SUSE. Originally released by the German company SuSE. It is popular for its centralized management tools. Similar to RedHat with Fedora, it supports the openSUSE project.
• Debian GNU/Linux. With one of the largest and oldest communities in the free software movement, it is the basis for distributions such as Xandros, Mepis, Linspire, Ubuntu and Linux Mint.

Operating systems descended from 4.4BSD are also popular:

• FreeBSD. Perhaps the most popular operating system of the family, of multiple purpose. With a very elaborate SMP implementation, it is the operating system used by Yahoo servers. And base of many operating systems among them Apple's Mac OS X.
• OpenBSD. Widely recognized for its proactive security and permanent audit of the source code. It is used in environments where security prevails above all, it is usually found installed on servers that act like Firewall, VPN or Proxy.
• NetBSD. It is known for its portability, to October 2008: 53 supported architectures. NASA has used it for research on satellite TCP/IP networks, as well as for recycling old computers with modern software.

The following UNIX implementations are historically significant, however they are currently deprecated:

• Tru64 UNIX currently by Hewlett-Packard (before Compaq and originally from Digital Equipment Corporation).
• UnixWare and SCO OpenServer formerly from Santa Cruz Operation and SCO Group, now from Xinuos (UnXis).
• NEC UX/4800.
• Silicon Graphics Inc IRIX..

Classic UNIX commands

Some basic UNIX commands are:

• Navigation/creation of directories/archives: ls cd pwd mkdir rm rmdir cp.
• File editing/vision: touch more ed vi nano.
• Text processing: echo cat grep sort uniq sed awk Thai head.
• File comparison: comm cmp diff patch.
• System administration: chmod chown ps find xargs sd w who.
• Communication: mail telnet ssh ftp finger rlogin.
• Shells: sh csh ksh.
• Documentation: man.

This is a list of the sixty user commands from section 1 of the First Edition:

ar as b bcd boot cat chdir check chmod chown cmp cp date db (Unix) dbppt dc dc dsw dtf du ed find for form hup lbppt ld ln ls mail mesg mkdir mkfs mount mv nm od pr rew (Unix) rkd rk rom

Other commands

• Time: lime