Back in the days of MS-DOS and 5Mhz 8088 CPU's with 640M of memory Advanced Voice, the company I worked for, ran an 8 port voice mail on an XT and it worked just fine. Matter of fact, when the ultra-fast 8Mhz and 12Mhz 80286's came out we ran a 24 port voice mail that worked great. The interesting thing is that every one else was trying to run C-coded voice mails, and struggling like hell to get them to work, our stuff just chugged along like the Energizer Bunny. And what was it programmed in? PC-Bus, aka Datapoint's Databus, an intrepreted database language. The actual source code is compiled into bytecode, which is intrepreted by a runtime interpreter. Note that 1CTI, the company that now uses that code, still runs it and it's evolved additions, except they're now compiled/run using the Sunbelt PL/B compiler/interpreter. Note that there are two versions, one for Windows and one for Linux. The basic code is the same, the difference being one uses Windows calls for some specialized stuff and the other uses Linux calls. Other than that, the code is the same. FYI, the code is an event-driven single-thread state machine.