We’re currently doing a new (non IE) system here with lots of Lintel, and lots of HW and SW issues so far.
If you go with AIX, you can mix and match Linux in, as AIX supports Linux on top of AIX.
With respect to ODBC, I suspect the Perl ODBC package could be used on either platform. I have set it up on an AIX box for a DBA. I’d be very surprised if it didn’t work equally as well.
I like the system management tools, robustness and maturity of the AIX platform, but if you’re looking to blaze new trails, go Linux.
Personally, for a large hospital production environment, I would stick to AIX, but a lot of it depends on the business continuity requirements of your applications.
Linux is a nice platform and “ready for prime time” in many respects, but to use a military metaphor, I’d rather ride into combat in an agile tank with lots of defensive weapons than to roll up in the (in)famous Bradley Fighting Vehicle. To me, AIX is like the more armored and better defended of the two. Linux can also do the job, but the HW robustness of the AIX HW platforms are hard to beat..