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AIX (Advanced Interactive eXecutive) is a proprietary operating system developed by IBM based on UNIX System V. Before the product was ever marketed, the acronym AIX originally stood for Advanced IBM UNIX.

AIX has pioneered numerous network operating system enhancements, introducing new innovations later adopted by Unix-like operating systems; it is often one of the first operating systems to implement a new innovation in software architecture as a sophisticated software technology.

The scalable AIX 5L 5.3 supports up to 64 central processing units and two terabytes (TB) of random access memory. The JFS2 file system—first introduced by IBM as part of AIX—supports computer files and partitions up to 16 TB in size.

Development

AIX V1, introduced in 1986, was based on System V Release 3. IBM later ported AIX to the RS/6000 platform as AIX/6000; since 1989, AIX has served as the RS/6000's primary operating system. In developing AIX, IBM and INTERACTIVE Systems Corporation (whom IBM contracted) also incorporated source code from Berkeley Software Distribution 4.2 and 4.3.

In the SCO v. IBM lawsuit filed in 2003, the SCO Group alleged that (among other infractions) IBM misappropriated licensed source code from UNIX System V Release 4 for incorporation into AIX; SCO subsequently withdrew IBM's license to develop and distribute AIX. IBM maintains that their license was irrevocable, and continues to sell and support the product pending the outcome of litigation.

Supported architectures

AIX on IBM Mainframes

In 1988, IBM announced AIX/370. AIX/370 was IBM's first attempt to offer Unix-like functionality for their mainframe line, specifically the System/370. AIX/370 was released in 1990 with functional equivalence to System V Release 2 and 4.3BSD as well as IBM enhancements. With the introduction of the ESA/390 architecture, AIX/370 was rebranded as AIX/ESA in 1991 and ran on the System/390 platform. Unlike AIX on its other platforms, AIX on the mainframe never ran as the host operating system, but rather as a guest under VM. AIX on the mainframe had little success and UNIX functionality was instead added as an option with the existing mainframe operating system, MVS, which became MVS/ESA OpenEdition in 1993.

Versions

  • AIX 4.3.3, September 1999
    • Added online backup function
    • Workload Management ( WLM )
  • AIX 4.3.2, October 1998
  • AIX 4.3.1, April 1998
  • AIX 4.3, October 1997
  • AIX 4.2.1, April 1997
    • NFS Version 3 support
  • AIX 4.2, May 1996
  • AIX 4.1.5, August 1996
  • AIX 4.1.4, October 1995
  • AIX 4.1.3, July 1995
  • AIX 4.1.1, October 1994
  • AIX 4.1, August 1994
  • AIX v4, 1994
  • AIX v3.2 1992
  • AIX v3.1
    • Introduction of Journaled File System (JFS)
  • AIX v3, February 1990
    • Developer release licensed only to OSF; the LVM was incorporated into OSF/1.
    • SMIT was introduced.
  • AIX v2
    • last version was 2.2.1.
  • AIX v1, 1986
    • last version was 1.3.

Interfaces

Graphical

The Common Desktop Environment (CDE) is AIX's default graphical user interface. As part of Linux Affinity and the free AIX Toolbox for Linux Applications (ATLA), open-source KDE and GNOME desktop are also available.

System Management Console

SMIT is the System Management Interface Tool for AIX. It allows a user to navigate a menu hierarchy of commands, rather than using the command line. Invocation is typically achieved with the command smit. Experienced system administrators make use of the F6 accelerator which generates the command line that SMIT will invoke to complete the proposed task. SMIT also generates a log of commands that are performed (smit.log), which can be condensed into a script for automating a series of tasks on numerous systems.

smit and smitty refer to the same program, though smitty invokes the text-based version, while smit will invoke an X Window based interface if possible; however, if smit determines that X Window capabilities are not present, it will present the text-based version instead of failing. Determination of X Window capabilities is typically performed by checking for the existence of the DISPLAY variable.

History

AIX Version 1

AIX version 1 was developed by IBM in conjunction with INTERACTIVE Systems Corporation, and was based in part on PC/IX, an operating system from Interactive Systems that ran on IBM/PC and compatible systems. Installation media consisted of eight 1.2M floppy disks.

AIX Version 2

AIX version 2 was a port of PC/IX to the IBM/RT Unix workstation. Unlike the IBM/PC, IBM/XT and IBM/AT systems, which were based on Intel 8086 and 80286 chips, respectively, the RT was based on the ROMP chip, the first commercial RISC chip ever, based on a design, the IBM 801, pioneered at IBM Research. I/O was provided by eight ISA bus slots. A typically configured RT came with 4MB of memory, maxing out at 16MB, and with a 20MB hard drive, upgradable to 300MB or more with external SCSI cabinets. Also standard were mouse and a 1280x1024 pixel-addressible 8-bit grayscale display and either a 4MB/sec token-ring network adapter, or a 10Mbit/sec 10Base2 (coaxial cable) ethernet adapter.

The performance of the RT, in comparison with other contemporaneous Unix workstations, was not outstanding. In particular, the floating point performance was poor, and was scandalized mid-life with the discovery of a bug in the floating point square root routine. Sales were also hobbled by the poor commission structure given to the IBM salesmen: it was structured along the same lines as the PC-class systems. With a typical price of about $20,000, which was much higher than the PC's, it was a hard sell. The resulting tiny commissions caused most of the IBM salesforce to be utterly disinterested in selling the product. Approximately 23,000 RTs were sold over the lifetime of the product, with some 4,000 going into IBM internal development and sales organizations.

One of the novel aspects of the RT design was the use of a microkernel. The keyboard, mouse, display, disk drives and network were all controlled by a microkernel, which allowed multiple operating systems to be booted and run at the same time. One could "hotkey" from one operating system to the next using the Alt-Tab key combination. Each OS in turn would get possession of the keyboard, mouse and display. Besides AIXv2, the PICK OS was built in this microkernel. The PICK was unique in being a unified operating system and database, and ran various accounting applications. It was popular with retail merchants, and accounted for about 4,000 units of sales.

Much of the AIXv2 kernel was written in the PL/I programming language, which proved troublesome during the migration to AIXv3. AIXv2 included full TCP/IP networking support, as well as SNA, and two networking file systems: NFS, licensed from Sun Microsystems, and Distributed Services or DS. DS had the distinction of being built on top of SNA, and thereby being fully compatible with DS on the IBM midrange AS/400 and mainframe systems. For the graphical user interfaces, AIXv2 came with the X10R3 and later the X10R4 and X11 versions of the X Window System from MIT, together with the Athena widget set. Compilers for Fortran and C were available. One of the more popular desktop applications was the PageMaker book publishing software.

AIX Version 3

The release of AIX version 3 coincided with the announcement of the first RS/6000 models. The RS/6000 was unique in that it not only outperformed all other machines in integer compute performance, but also beat the competition by a factor of 10 in floating-point performance.

AIXv3 innovated in several ways on the software side. It was the first operating system to introduce the idea of a journalling file system, JFS, which allowed for fast boot times by avoiding the need to fsck the disks on every reboot. Another innovation was the introduction of shared libraries, which avoided the need for an application to statically link to the libraries it used. The resulting smaller binaries used less of the hardware RAM, to run, and used less of the disk space to install. Besides improving performance, it was a boon to developers: executable binaries could be in the 10s of Kbytes instead of a megabyte for an executable statically linked to the C library. AIXv3 also ditched the microkernel of AIXv2, a contentious move that resulted in v3 being somewhat more "pure" (and containing no PL/1 code) than v2.

Other notable subsytems included:

  • IrisGL, a 3D rendering library, the progenitor of OpenGL. IrisGL was licensed by IBM from SGI, then a small company which had sold only one thousand machines to date. SGI also provided the low-end graphics card for the RS/6000, capable of drawing 20,000 Gouraud-shaded triangles per second. The high-end graphics card was designed by IBM, a follow-on to the mainframe-based IBM 5080, capable of rendering 990K vectors per second.
  • PHIGS, another 3D rendering API, popular in automotive CAD/CAM circles, and at the core of CATIA.
  • Full support for version 11 of the X Window System, together with Motif as the recommended widget collection and window manager.
  • Network file systems: NFS from Sun; AFS, the Andrew File System; and DFS, the Distributed File System.
  • NCS, the Network Computing System, licensed from Apollo Computer (later purchased by HP)
  • The NeXT windowing system. This was notable as a "plan B", in case the X11/Motif/IrisGL combination failed in the marketplace. In almost every way, NeXT was a better technology, and had better and more interesting features than X11/Motif. However, it was highly proprietary: it hadn't been licensed to any other Unix vendor. This, in the face of the open systems challenge of X11/Motif and its lack of 3D support, cemented its failure in the marketplace.

See also

  • AOS, IBM's educational-market port of 4.3BSD

External links

IBM software | Operating systems | System V

AIX | AIX | AIX | AIX | AIX | Advanced interactive executive | AIX 운영 체제 | AIX | AIX | AIX | Advanced Interactive eXecutive | AIX | AIX | Advanced Interactive eXecutive | AIX | AIX | AIX | AIX | AIX

 

This article is licensed under the GNU Free Documentation License. It uses material from the "AIX operating system".

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