IBM AIX (operating system)

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AIX

Website:	IBM AIX 5L
Company/ developer:	IBM
OS family:	UNIX System V
Source model:	Closed source
Latest stable release:	5L 5.3 / August, 2004
Kernel type:	Dynamic Extendable
Default user interface:	Common Desktop Environment
License:	Proprietary
Working state:	Current

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.

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.

Contents 1 Development 2 Supported architectures 2.1 AIX on IBM Mainframes 2.2 AIX on Apple hardware 3 Versions 4 Interfaces 4.1 Graphical 4.2 System Management Console 5 History 5.1 AIX Version 1 5.2 AIX Version 2 5.3 AIX Version 3 6 See also 7 External links 7.1 Programming in the AIX environment

[edit] 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.

[edit] Supported architectures

• AIX v1 supported IBM PS/2 Micro Channel architecture PCs and IBM RT.
• AIX v2 supported 6150-series IBM RT systems.
• AIX v3 introduced support for IBM POWER architecture.
• AIX v4 introduced support for PowerPC architecture and PCI bus.
• AIX v5 introduced support for IA64 architecture (although AIX for Itanium never went beyond beta). [1]
  • AIX v5.1 introduced Logical Partitioning on POWER4, was last version to support Micro Channel architecture.
  • AIX v5.2 introduced support for JS20 PowerPC 970 based blade for IBM BladeCenter.
  • AIX v5.3 introduced MicroPartitioning on POWER5.
  • AIX v5.4 introduced Partition mobility on POWER6.

[edit] 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, with its kernel source code based on OSF/1, and ran on the System/390 platform. This development effort was made partly to allow IBM to compete with Amdahl UTS. 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 UNIX functionality was added as an option to the existing mainframe operating system, MVS, which became MVS/ESA OpenEdition in 1993.

[edit] AIX on Apple hardware

The Apple Network Server systems were PowerPC-based systems designed by Apple Computer to have numerous high-end features that standard Apple hardware did not have, including swappable hard drives, redundant power supplies, and external monitoring capability. These systems were more or less based on the Macintosh hardware available at the time but were designed to use AIX as their native operating system.

Although at the time it was the only branded Unix system available on PowerPC-based hardware, AIX was only available on the Network Servers and was not ported to standard Macintosh hardware. Earlier Apple Unix systems used A/UX; later Apple Computer systems use Mac OS X, which has functional Unix-like underpinings but does not carry Open Group branding.

[edit] Versions

• AIX 5L 5.3, August 2004
  • NFS Version 4 support
  • Advanced Accounting
  • Virtual SCSI
  • Virtual Ethernet
  • Simultaneous multithreading (SMT) support
  • Micro-Partitioning support
  • POWER5 support
  • JFS2 quota support
  • JFS2 filesystem shrink support
• AIX 5L 5.2, October 2002
  • Minimum level required for POWER5 hardware
  • Support for MPIO Fibre Channel disks
  • iSCSI Initiator software
  • Dynamic LPAR support
• AIX 5L 5.1, May 2001
  • Minimum level required for POWER4 hardware and the last release that supported Micro Channel architecture
  • Introduction of 64-bit kernel, installed but not activated by default
  • JFS2
  • Static LPAR support
  • The L stands for Linux affinity
  • Trusted Computing Base (TCB)

• 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
  • Support for 64-bit architecture
  • Support for IPv6
• 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
  • CDE 1.0 became the default GUI environment, replacing Motif X Window Manager.
• 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 v2.0
  • last version was 2.2.1.
• AIX v1, 1986
  • last version was 1.3.

[edit] Interfaces

[edit] 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.

[edit] 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 function key which generates the command line that SMIT will invoke to complete the proposed task.

SMIT also generates a log of commands that are performed in the smit.script file. The smit.script file automatically records the commands with the command flags and parameters used. The smit.script file can be used as an executable shell script to rerun system configuration tasks. SMIT also creates the smit.log file, which contains additional detailed information that can be used by programmers in extending the SMIT system.

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.

[edit] History

[edit] 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.

[edit] 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 4 MB of memory, maxing out at 16 MB, and with a 20 MB hard drive, upgradable to 300 MB or more with external SCSI cabinets. Also standard were mouse and a 1280x1024 pixel-addressable 8-bit grayscale display and either a 4 MB/s token-ring network adapter, or a 10 Mbit/s 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.

[edit] 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.^{[citation needed]}

Releases of AIX version 3 also took advantage of the developments in the POWER architecture, which featured in the POWER 5 processors, like logical partitioning, dynamic logical partitions and advanced virtualization.

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.

[edit] See also

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

[edit] External links

• IBM AIX 5L
• AIX Wiki
• AIX 5L Technical Forum
• AIX & UNIX dW Zone
• AIX Toolbox for Linux Applications
• AIX fixes
• AIX/ESA V2R2 General Information
• AIX Hints & Tips
• AIX Business Continuity Standards

[edit] Programming in the AIX environment

• AIX Version 4.3 General Programming Concepts: Writing and Debugging Programs