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AIX History

AIX and Unix:

The history of AIX starts with the history of Unix. In the 1960s at AT&T's Bell Labs research center, Ken Thompson and Dennis Ritchie were working on a "new" Operating System called: Multics (Multiplexed Information and Computer Services). It was a big complex system (it was capable to grow in size by simply adding more resources, like computing power, main memory, or disk storage.) Although it was very complex, some basic concepts were useful, like the concept of a shell, processes, hierarchical file system structure. In 1969 Multics project ended, but the developers decided to continue privately. They implemened the good parts from Multics with a different design philosophy, focusing on keeping the system small and simple. Then came the name of Unix (originally Unics) as the opposite of Multics, which was: "overdesigned and overbuilt and over everything. It was close to unusable" said Ken Thompson.

In the 1970s Unix started to be popular in Universities. It was not possible to buy the Unix operating system (as an installation package), which could be run on any computer. If somebody wanted to use it, the source code had to be modified to the actual hardware. With this approach during the years different flavors of Unix systems started to emerge, and one of them was in 1986, the AIX.

AIX stands for Advanced Interactive eXecutive, and this strange name and abbreviation comes from a company name: Interactive Systems Corporation
Interactive Systems Corporation (or ISC) was a software company and they had a contract with IBM. They developed several products to IBM, for example to personal computers (PCs) they  created PC-IX (Personal Computer Interactive eXecutive) and they also developed the AIX 1.0 (Advanced Interactive Executive) for the IBM RT PC under contract to IBM.

AIX history:

IBM had 2 discrete Power Architecture hardware lines, based on different Operating Systems:
    - OS/400, later i5/OS, more later IBM i
    - AIX (on the same hardware it is possible to run Linux as well)

I. 1986-1990 (AS/400 - IBM RT):
In 1986 AIX Version 1 had been introduced for the IBM 6150 RT workstation, which was based on UNIX.
In 1987 for the other product line: OS/400 (later i5/OS and IBM i), the platform (hardware) AS/400 had been released.

II. 1990-1999 (RS/6000):
Among other variants, IBM later produced AIX Version 3 (also known as AIX/6000), for their IBM POWER-based RS/6000 platform. The RS/6000 family replaced the IBM RT computer platform in February 1990, and was the first computer line to see the use of IBM's POWER and PowerPC based microprocessors. Since 1990, AIX has served as the primary operating system for the RS/6000 series.

AIX Version 4, introduced in 1994, added symmetric multiprocessing with the introduction of the first RS/6000 SMP servers and continued to evolve through the 1990s, culminating with AIX 4.3.3 in 1999. RS/6000 was renamed eServer pSeries in October 2000.

III. 2000-2004 (eServer pseries):
IBM eServer was a family of computer servers from IBM Corporation. Announced in the year 2000, it combined the various IBM server brands (AS/400, RS/6000...) under one brand.

The various sub-brands were at the same time rebranded from:
    - IBM AS/400 to IBM eServer iSeries, i for Integrated.
    - IBM RS/6000 to IBM eServer pSeries, p for POWER

They merged to use essentially the same hardware platform in 2001/2002 with the introduction of the POWER4 processor. After that, there was little difference between both the "p" and the "i" hardware; the only differences were in the software and services offerings. AIX 5.2 was introduced in October 2002.

IV. 2004-2008 (IBM system i and p):
In 2005 announced a new brand, 'IBM System' as an umbrella for all IBM server and storage brands:
    - IBM eServer iSeries became IBM System i
    - IBM eServer pSeries became IBM System p

With the introduction of the POWER5 processor in 2004, even the product numbering was synchronized. The System i5 570 was virtually identical to the System p5 570. AIX 5.3 was intoduced in August of 2004. In May 2007 IBM launched its POWER6 and AIX 6.1 in November 2007.

V. 2008-present (Power Systems):
In April of 2008, IBM officially merged the two lines of servers and workstations under the same name, Power Systems, with identical hardware and a choice of operating systems, software and service contracts.

Power Systems is the name of IBM's unified Power Architecture-based server line, merging both System i and System p server platforms, and running either IBM i (formerly i5/OS and OS/400), AIX or Linux operating systems. Power Systems was announced April 2, 2008.

In February of 2010, IBM announced new models with new POWER7 microprocessor and AIX 7.1 in September 2010.

In August 2012 IBM introduced the POWER7+ processor. It is an updated version of POWER7 with higher speeds, more cache and integrated accelerators.

In June 2014 new systems based on POWER8 became available from IBM. POWER8 is designed to be a massively multithreaded chip, with each of its cores capable of handling eight hardware threads simultaneously. The processor makes use of very large amounts of caches, which enable very high bandwidth to memory and system I/O. For most workloads, the chip is said to perform two to three times as fast as its predecessor, the POWER7.

AIX 7.2 was announced in October 2015. Its principal feature is the Live Kernel Update capability which allows OS fixes to replace the entire AIX kernel with no impact to applications. AIX 7.2 was also restructured to remove obsolete components. The networking component, bos.net.tcp.client was repackaged to allow additional installation flexibility (SR-IOV enhancement). AIX 7.2 is only supported on systems based on POWER7 or later processors.

In 2016 POWER9 was announced, and with 14 nm technology and the 3.9 GHz speed, POWER9 boxes have up to 50% more performance than POWER8 boxes in default ship mode. In fact, compared to POWER7+, POWER9 offers over 2x more per core capacity. When running AIX 7.2 TL 3 on POWER9, the SMT mode will automatically default to SMT8.


sureshraavi said...

what are the features ofaix 7.1 version compare to lower versions

aix said...

A full description can be found in AIX 7.1 Differences Guide: http://www.redbooks.ibm.com/abstracts/sg247910.html

Anonymous said...

what are key difference between 5.3 and 6.1 oslevels

aix said...

I would suggest to read AIX 6.1 Differences Guide: http://www.redbooks.ibm.com/abstracts/sg247559.html

Some headlines from that book:
-Disabling JFS2 logging
-Encrypted filesystem
-WPAR enhancements
-Enhanced DUMP facility

Anonymous said...

I got a question in interview, what is landscape of AIX ? Can you explain this?

aix said...

Hi, your question is not so precise, but a possible answer could be "IBM Power Systems".

Anonymous said...

Hi, I am also not clear on this question.. Thanks for your reply

Anonymous said...

k k

Anonymous said...

You're missing AIX 1.x for the PS/2 and i386. (Discontinued in 1992)

aix said...


Anonymous said...

I started working with AIX 2.6 with about 50 3.5" floppy disks on a IBM 386 Microbus personal computer. You had to start over if you put the wrong disk in the wrong order into that PC. Those were the days.

aix said...

Wow..that is something. I would really love to hear some more experiences of those days. How was a Sysadmin life at that time? What bugs/problems were usual?

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Priyank Arora said...

IBM has invested billions for Linux R&D. What is the future of AIX in upcoming years? Will IBM continue to release newer versions of AIX?

aix said...

yes, I think so.

Unknown said...

Can you update the AIX releases after 2008 till date?

Anonymous said...

Thanks for the info.