TRAPS and SIQ issues, high licensing costs, and no real support from anyone. Fail. I am sorry.
TRAPS:OS/2 doesn't trap as much as Windows bluescreens in such setups (ATMs - or the old bank workstations running Warp 3 or 4 on IBM PCs). The ATM manufacturers worked with IBM to choose the best hardware for their machines and OS/2. As a for instance, my 8 year old Netfinity has
never ever ever ever trapped (or crashed) - ever.
SIQ Issues:SIQ Issues are programming issues. It's not so much that the GUI doesn't respond (which it doesnt - but that's not the REAL issue), but more accurately that, even though it is spelled out multiple times in multiple places in the IBM Docs, programmers don't follow IBM's programming rules - if they did, a program would have a separate thread monitoring it's queue messages ensuring there was never a queue deadlock.
Thus, the SIQ "fix" later added to Warp is actually a "Well, we wrote this to deal with programs that were not written properly because the programmers did not follow the instructions" routine.
HIGH LICENSING COST:Windows, in such an environment, is just as if not MORE expensive in terms of licensing. As a matter of fact, technical merits aside (at the time I chose OS/2 for my servers, over a decade ago), one big consideration was in order to have the ability to have more than a few clients connected at a time, I had to pay MS out the ____ to enable that functionality - not so with OS/2 - no artificial user limits are imposed.
You also are not taking into account the plethora of updates, anti-virus software, anti-spyware software, real firewall software, external firewall, a FAR larger support team* (and on and on) that a Windows box needs - which drives up that cost even more. In the end, a Windows based solution is FAR more expensive.
* As for the "a far larger support team" comment, almost 10 years ago, IBM was bidding against... IBM... (no joke - two different divisions) for a support contract for Bank of America for ALL their OS/2 boxes (workstations AND ATMs). The division of IBM that was going to sub-contract some of the work out to me lost (sadly) - but basically, I (and 1 other person who worked with me) would have been responsible for the entire Eastern Seaboard of the United States. If these were Windows setups, you'd be looking at a support team in the dozens or hundreds. Add up that cost difference.Real Support:Just like they do with MS, the ATM vendors have support contracts with IBM. Even today, many of them do, simply because there are still many ATMs that use OS/2. So, needless to say, both (a) the ATM manufacturers have their own dedicated Warp/ATM support team, as well as (b) reps within IBM to provide that team with additional support if the need arises.
Hope that answers your questions and concerns on those issues.
-Robert