Overview of AIX

AIX is based on standard System V. Most Systems Administrators tend to "fall in love" with the first UNIX version they get to know. They assume all other UNIX or Linux versions are odd, quirky, plain wrong, or bad. But this is not really the case and once you are on to your third or fourth UNIX version you see the common ground between versions is large, each version has its own strengths. and that the prime area of differences is the system admin tools. The current release of AIX is AIX 6.1. Older versions (V5.1, V5.2, v5.3) are still supported and have higher TL / ML numbers. Older still is AIX V4, which is no longer supported but still in use. You can (if you purchase support) ask questions and get answers regarding V4 but IBM will not provide fixes or updates. Read the Wikipedia article on AIX for lots of background information AIX on Wikipedia The logo to the left has a "secret 5" in it - can you see it?

AIX strengths:

• It is based on UNIX System V and has much in common with other versions of UNIX.
• System Management Interface Tools smit and smitty. These are very good system admin tools and cover 95% of your admin work. If you want to learn AIX command line interfaces, just hit F6 and smitty will tell you what commands it will use.
• The IBM compilers for AIX are very good but fussy about your code. Other compilers may let you get away with ambiguous code and make assumptions, but IBM compilers will issue warning messages where your code (for example) relies on side effects or ordering that is not defined in the C standards. Initially, this is a pain but it ultimately makes the code more robust. IBM compilers cost extra. GCC compilers are also available - see Open Source below.
• Built in Logical Volume Manager (LVM) - AIX was developed from day one assuming large systems and lots of disks and so has an LVM to manage groups of disks. Some of the terms used may be different than those of other UNIX versions but the LVM is flexible, powerful, and easy to use. LVM is delivered with base AIX.
• AIX has a Journaling Filesystem (JFS2) which supports multi-TB filesystems. The older JFS filesystem is still available, too. Both are delivered with base AIX.
• Workload Manager (WLM) allows multiple applications to be segregated into classes and resources (CPU time, memory, and disk I/O) assigned to the classes, which allows coexistence, monitoring, and management of multiple workloads on a single OS image. (Think Solaris Containers.) WLM is delivered with base AIX.
• HACMP - High Availability Cluster Multiprocessing allows AIX to run a cluster of machines with automated take-over and/or fail-over of applications and data between machines. HACMP is recommended for all critical solutions where minimum downtime is a requirement. HACMP is a separate product which runs on AIX.
• Reliability, Availability and Serviceability (RAS) - marketing speak for a) things don't break often, b) if something breaks, the machine usually either keeps running or comes back up immediately after crashing with the failing component offline, and c) the machine is usually able to identify the failing component and the failing component can often be replaced while the machine continues to run. RAS is built in to AIX and the underlying hardware. For example, POWER4 and POWER5 CPUs can sometimes detect internal errors before they become critical. AIX can then stop scheduling work to the failing CPU and take it offline while applications continue to run.
• Logical Partitions (LPARs) - machines with POWER4 and POWER5 CPUs can be partitioned to run multiple copies of AIX (and/or Linux) at the same time. Workloads formerly run on multiple machines can be run on a single machine, allowing hardware resources to be dynamically (without reboot when running AIX V5.2, V5.3, or Linux) moved as workloads fluctuate. If workloads mesh well (encounter peak loads at different times of the day, week, month, or year), workloads consolidated onto a single machine can be run with fewer resources than required to run them on multiple separate machines, thereby reducing cost. AIX does its part to support the LPAR infrastructure and cooperate with the machine firmware, referred to as the Hypervisor.
• Micro-partitioning - LPARs can share CPUs, which the Hypervisor time-slices. (Requires AIX V5.3 or the Linux 2.6 kernel.)
• Virtualization - LPARs can share disks (and disk & network adapters) to reduce costs. (Requires AIX V5.3 or the Linux 2.6 kernel.)

AIX admin interfaces

• smitty - the system admin's favorite command
• smit - as above but for X-Windows, a GUI but runs more slowly
• WebSM - Web based Systems Manager

AIX General Information

Subject	Comments
AIX website	The top level website on AIX
Overview and Highlighted features	Various Articles and features os AIX covered here
Manuals for pSeries and AIX	Reference material
UNIXguide	Website compares AIX with FreeBSD, HP-UX, RedHat Linux, Solaris and Tru64. This can be a good way to learn and compare commands but note the bulk of system admin commands in AIX are better covered by using smitty.
AIX From Strength to Strength	This is a summary of upgrade benefits for AIX®, Bonus Pack, Web Download Pack and Expansion Pack. This document details each release of AIX and the new features added.
Downloadable Redbook Technical Manuals	Loads of hands on technical books for you to download in .PDF format

Getting hold of AIX

• Most of the time AIX is supplied with a machine (OK it comes separately but is purchased with the machines) but many customers now buy machines without AIX when they intend to run Linux on POWER.
• You can only order AIX media (usually CDs but DVD for the latest version are starting to become available), if you sign up and pay for an AIX support contract.
• You can, however, get AIX updates via a download from the IBM Fix Central website at http://www.ibm.com/eserver/support/fixes/
  then select: "UNIX Servers" followed by "AIX Operating System" followed by the AIX release you want to update (4.3, 5.1, 5.2 and 5.3) and either Maintenance Level or the new Technology Level. You will be asked for the current level of your software and then the packages you need can be downloads. But one warning - many of these are a few hundreds of MBs, so give yourself plenty of time and space for the download.

Hardware:

AIX runs on IBM RS/6000, pSeries, p5 and System p servers. These are all the same server range with the same binary compatible CPUs under the PowerPC architecture. Cynics might say that the name changes only make sense to IBM marketing!!!

Does AIX come with compilers?

The answer is no - under the name of VisualAge or XL compilers these available from IBM at extra costs.

You have a number of options:

1. Purchase the compiler
2. You can however, download these from the IBM website for evaluation purposes - unfortunately, these are well hidden on the website and even move about so there is no point giving you a URL for a download link!! Goto http:www.ibm.com than the link to "Products", then take the link for "Software by category", then the link for "Traditional Programming Languages" Once you find what you want (and don't forget there many be more than one, for example C & C++ compiler and the VisualAge C compiler) take the "Trials and Betas" option on the far left and ... well good luck.
3. Use the GNU compiler collection that you can download for free - see the AIX and Open Source link on the main AIX wiki page.

The postings on this site solely reflect the personal views of the authors and do not necessarily represent the views, positions, strategies or opinions of IBM or IBM management.