development of Unix and Unix-like systems, starting in 1969 A Unix-like ( sometimes referred to as UN*X or *nix ) operate system is one that behaves in a manner alike to a Unix system, although not inevitably conforming to or being certified to any adaptation of the Single UNIX Specification. A Unix-like lotion is one that behaves like the match Unix command or shell. There is no technical standard defining the term, and opinions can differ about whether or the degree to which a particular operating system or application is Unix-like.
Reading: Unix-like – Wikipedia
The condition can include free and open-source operate on systems inspired by Bell Labs ‘ Unix or designed to emulate its features, commercial and proprietary workalikes, and versions based on the license UNIX source code, which may be sufficiently Unix-like to pass certification and bear the UNIX hallmark .
The Open Group owns the UNIX trademark and administers the Single UNIX Specification, with the “ UNIX ” diagnose being used as a certificate sign. They do not approve of the construction “ Unix-like ”, and consider it a pervert of their trademark. Their guidelines require “ UNIX ” to be presented in uppercase or otherwise distinguished from the surrounding text, powerfully encourage using it as a post adjectival for a generic bible such as “ system ”, and discourage its use in hyphenate phrases. [ 1 ] other parties frequently treat “ Unix ” as a genericized trademark. Some add a wildcard character to the name to make an abbreviation like “ Un*x ” [ 2 ] or “ *nix ”, since Unix-like systems much have Unix-like names such as AIX, A/UX, HP-UX, IRIX, Linux, Minix, Ultrix, Xenix, and XNU. These patterns do not literally match many arrangement names, but are silent by and large recognized to refer to any UNIX system, descendant, or work-alike, even those with wholly dissimilar names such as Darwin / macOS, illumos / Solaris or FreeBSD. In 2007, Wayne R. Gray sued to dispute the status of UNIX as a brand, but lost his case, and lost again on entreaty, with the court upholding the hallmark and its possession. [ 3 ] [ 4 ]
Simplified history of Unix-like operating systems “ Unix-like ” systems started to appear in the former 1970s and early 1980s. many proprietary versions, such as Idris ( 1978 ), UNOS ( 1982 ), Coherent ( 1983 ), and UniFlex ( 1985 ), aimed to provide businesses with the functionality available to academician users of UNIX. When AT & T allowed relatively cheap commercial binary sub-licensing of UNIX in 1979, a diverseness of proprietorship systems were developed based on it, including AIX, HP-UX, IRIX, SunOS, Tru64, Ultrix, and Xenix. These largely displaced the proprietary clones. Growing incompatibility among these systems led to the initiation of interoperability standards, including POSIX and the Single UNIX Specification. versatile complimentary, low-cost, and unrestricted substitutes for UNIX emerged in the 1980s and 1990s, including 4.4BSD, Linux, and Minix. Some of these have in turn been the footing for commercial “ Unix-like ” systems, such as BSD/OS and macOS. several versions of ( Mac ) OS X/macOS running on Intel-based Mac computers have been certified under the Single UNIX Specification. [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ] The BSD variants are descendants of UNIX developed by the University of California at Berkeley with UNIX source code from Bell Labs. however, the BSD code basis has evolved since then, replacing all of the AT & T code. Since the BSD variants are not certified as compliant with the Single UNIX Specification, they are referred to as “ UNIX-like ” rather than “ UNIX ” .
Dennis Ritchie, one of the original creators of Unix, expressed his public opinion that Unix-like systems such as Linux are de facto Unix systems. [ 12 ] Eric S. Raymond and Rob Landley have suggested that there are three kinds of Unix-like systems : [ 13 ]
Those systems with a historical connection to the AT & T codebase. Most commercial UNIX systems fall into this category. so do the BSD systems, which are descendants of work done at the University of California, Berkeley in the late 1970s and early 1980s. Some of these systems have no master AT & T code but can inactive trace their lineage to AT & T designs.
Trademark or branded UNIX.
These systems—largely commercial in nature—have been determined by the Open Group to meet the Single UNIX Specification and are allowed to carry the UNIX name. Most such systems are commercial derivatives of the System V code floor in one form or another, although Apple macOS 10.5 and late is a BSD variant that has been certified, EulerOS and Inspur K-UX are Linux distributions that have been certified, and a few other systems ( such as IBM z/OS ) earned the hallmark through a POSIX compatibility layer and are not otherwise inherently Unix systems. many ancient UNIX systems nobelium long meet this definition .
broadly, any Unix-like system that behaves in a manner roughly consistent with the UNIX specification, including having a “ platform which manages your login and command line sessions “ ; [ 14 ] more specifically, this can refer to systems such as Linux or Minix that behave similarly to a UNIX system but have no genic or trademark joining to the AT & T code base. Most free/open-source implementations of the UNIX purpose, whether genic UNIX or not, fall into the restrict definition of this third category due to the expense of obtaining Open Group documentation, which costs thousands of dollars [ citation needed ] for commercial closed source systems. Around 2001, Linux was given the opportunity to get a authentication including free assistant from the POSIX chair Andrew Josey for the emblematic price of one dollar. [ citation needed ] There have been some activities to make Linux POSIX-compliant, with Josey having prepared a list of differences between the POSIX standard and the Linux Standard Base stipulation, [ 15 ] but in August 2005, this project was shut down because of missing matter to at the LSB knead group. [ citation needed ]
Some non-Unix-like manoeuver systems provide a Unix-like compatibility layer, with varying degrees of Unix-like functionality .
other means of Windows-Unix interoperability admit :
- The above Windows packages can be used with various X servers for Windows
- Hummingbird Connectivity provides several ways for Windows machines to connect to Unix and Linux machines, from terminal emulators to X clients and servers, and others
- The Windows Resource Kits for versions of Windows NT include a Bourne Shell, some command-line tools, and a version of Perl
- Hamilton C shell is a version of csh written specifically for Windows.