. . MS-DOS programs I wrote in Turbo Pascal many years ago - plus they're still running a DOS version of BusinessWorks accounting (which Sage said wasn't Y2K compliant - but guess what). They're running all this on OS/2, often two or three instances of each program on each workstation so they can be in different parts of the program at the same time.
All these programs run like stink, without flaw and never crash. It's a heavily networked environment and the fax server (FaxWorks LAN for OS/2) is busy all day supporting outgoing traffic from 12 workstations. They have redundant servers running Debian Sarge.
Their competitors are completely mystified how then can instantly answer inquiries that require a "Let me call you back on that" everywhere else.