AIX (pronounced /ˌeɪ.aɪ.ˈɛks/ ay-eye-EKS[5]) is a series of proprietary Unix operating systems developed and sold by IBM since 1986.

IBM has continuously enhanced the software with features such as processor, disk, and network virtualization, dynamic hardware resource allocation (including fractional processor units), and reliability engineering concepts derived from its mainframe designs.

[8] Unix began in the early 1970s at AT&T's Bell Labs research center, running on DEC minicomputers.

By 1976, the operating system was used in various academic institutions, including Princeton, where Tom Lyon and others ported it to the S/370 to run as a guest OS under VM/370.

[9] This port later grew into UTS,[10] a mainframe Unix offering from IBM's competitor Amdahl Corporation.

In the late 1990s, under Project Monterey, IBM and the Santa Cruz Operation attempted to integrate AIX and UnixWare into a multiplatform Unix for Intel IA-64 architecture.

[17] In 2003, the SCO Group filed a lawsuit against IBM, alleging misappropriation of UNIX System V source code in AIX.

[19] According to its developers, the AIX source (for this initial version) consisted of one million lines of code.

One of the novel aspects of the RT design was the use of a microkernel, called Virtual Resource Manager (VRM).

For the graphical user interfaces, AIX v2 came with the X10R3 and later the X10R4 and X11 versions of the X Window System from MIT, together with the Athena widget set.

[19] AIX PS/2, first released in October 1988,[21] ran on IBM PS/2 personal computers with Intel 386 and compatible processors.

nroff and troff for AIX were also sold separately in a Text Formatting System package priced at $200.

The X Window System package was priced at $195, and featured a graphical environment called the AIXwindows Desktop, based on IXI's X.desktop.

[citation needed] Unlike AIX/370, AIX/ESA ran both natively as the host operating system, and as a guest under VM.

AIX/ESA, while technically advanced, had little commercial success, partially because[citation needed] UNIX functionality was added as an option to the existing mainframe operating system, MVS, as MVS/ESA SP Version 4 Release 3 OpenEdition[29] in 1994, and continued as an integral part of MVS/ESA SP Version 5, OS/390 and z/OS, with the name eventually changing from OpenEdition to Unix System Services.

As part of Project Monterey, IBM released a beta test version of AIX 5L for the IA-64 (Itanium) architecture in 2001, but this never became an official product due to lack of interest.

These systems were more or less based on the Power Macintosh hardware available at the time but were designed to use AIX (versions 4.1.4 or 4.1.5) as their native operating system in a specialized version specific to the ANS called AIX for Apple Network Servers.

Experienced system administrators make use of the F6 function key which generates the command line that SMIT will invoke to complete it.

Determination of X Window System capabilities is typically performed by checking for the existence of the DISPLAY variable.

[citation needed] Object Data Manager (ODM) is a database of system information integrated into AIX,[58][59] analogous to the registry in Microsoft Windows.