First post, by dsimcha
I have come across an interesting fact concerning the original Jetfighter game. Apparently, it does not even run on newer CPUs in pure DOS. I remember seeing, back in the 386 days, a warning in the instruction manual for this game that it may not work on some 486DX2 CPUs. It worked fine, of course, on my 386 under DOS. However, it has not worked under pure DOS (i.e. no Windows, just a bootable MS-DOS floppy or a restart in MS-DOS mode in Win 9x) on the following CPUs: AMD K6, AMD K6-2, AMD Athlon XP, Intel Pentium II Celeron, Intel Pentium III, and Intel Pentium 4 Celeron. It fails on these CPUs the same way it does in DOSBox: It freezes at the title screen. Also, I noticed that DOSBox, according to Windows 3.1 MSD, appears to emulate a 486DX in all core modes. Is it possible that this and maybe a few other games could be made to work by using very strict 286 or 286 emulation, rather than 486 emulation? Maybe there were some bugs in Intel and AMD's real mode where there were minor incompatibilities w/ a small amount of old binaries.