1) AIX is a commercial product. You need a Software Subscription Contract with IBM to get the base level filesets of the
system software.
Updates are available for free, but cannot be applied without the (payable) base levels being installed.
Here is the AIX Information Center, containing all the links you might need:
http://publib16.boulder.ibm.com/pseries/en_US/infocenter/base/aix52.htm
Appli
cation Software, if not Open Source (see below) is always payable, coming from lots of manufacturers and vendors:
http://www.ibm.com/solutions/us/en/?cm_re=masthead-_-business-_-more2) "installp" is the fundamental installation tool for AIX. Its companions are e.g. "lslpp" for listing/reporting purposes besides other tools like e.g. bffcreate.
Best issue "smitty install" to see all the tools and options.
3) IBM has a so-called "Toolbox for Linux Applications", which is shipped as a CD with AIX, but since it's all Open Source the software is available for download as precompiled rpm packages at no charge here:
http://www-03.ibm.com/systems/power/software/aix/linux/toolbox/alpha.html
Another great source for IAX RPMs is http://www.perzl.org
There are some more places where to find AIX RPMs. Google for it!
4) The (only) method to install this Open Source software is RPM (which is part of AIX), if you don't want to compile the source code by yourself.
The GNU CompilerCollection is available from the toolbox.
The common method to download is HTTP or FTP, depending on the site offering the product in question.
5) As for Apache - there are several other sources besides the toolbox.
There are things like the (payable) IBM HTTP server which is based on apache:
http://www-01.ibm.com/software/webservers/httpservers/ and there is always the source code from
apache.org:
http://httpd.apache.org/wm
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