[lamontcg]

I worked at Chef Software up until last year and we maintained binary distributions of the software (including ruby and lots of lower level libraries) that were built on Solaris, AIX and Windows in addition to Ubuntu, RHEL and FreeBSD.

Most customers were on Ubuntu/RHEL/Windows. There was very little on FreeBSD, AIX or Solaris. We had zero interest for HP-UX, I think that is dead enough to be ignoreable. Banks and financial services have a tendency towards AIX, while Solaris I think was primarily one customer that had a lot of legacy. AIX and Windows were the biggest pain in the ass, but every time we tried to kill support for it, people discovered sizable contracts that had been signed with us (yeah, our tracking in salesforce was bad).

My background is that I learned C and Unix on a Tandy 6000 back in 1989/1990, then in college used and worked on a wide variety of O/Sen (Dynix, BSD4.3, Digital Unix 4.0, SunOS 4.1.4, Solaris 2.4+, Irix 5.x/6.x (i think), something that ran on a VAX, NetBSD and later Linux). I ported NMAP to a bunch of those and did the original GNU autoconf work on it. I've been mostly Linux since 2001 (Amazon from 2001-2006).

[divbzero]

Is AIX functionally superior for banks and financial services? Or is it a matter of legacy software requiring AIX?

[lamontcg]

I can't really answer that, but my general impression is that they actually like it and it isn't just legacy (or at least some of them).

[dillab2]

As somebody who likes it I think I would explain it along the lines of FreeBSD vs Linux.

AIX is a complete package OS with some nice enterprise features, and it is modern and similar enough to make porting from Linux not too terribly difficult. Even something like RHEL is still very much more in the Linux tradition of lots of pieces of independently developed software kinda thrown together and called an OS, at times haphazardly.

That being said, we of course run RHEL as well, but mostly for cost reasons for less important applications, as opposed to any particular dislike for AIX.

USS on zOS is a much more difficult IBM UNIX to work with in my opinion, and tends to generate stronger opinions from both sides of the proprietary/OSS fence. They are making progress, but the compiler and compatibility situation is not as good as POWER/AIX.