DOS ain't dead

keyboard problem in details (Announce)

posted by jaybur  , UK, 09.01.2008, 13:13

> This behaviour makes it safe for DOS TSR programs, which have hooked
> interrupt vector 9, to read port 60h and then call the old interrupt
> handler (which will > repeat the port 60h read access and get the very same
> data).

Hmm, sounds to me like it's really a bug of any DOS TSR that relies on this rather precarious assumption, especially if it enables interrupts before calling the old handler. Either way, multiple accesses to ports that have "side-effects" like this is always asking for trouble.

Complete thread:

• Qemu 0.9.1 is out ... - Japheth, 08.01.2008, 08:53 (Announce)
  • Qemu 0.9.1 is out ... :-( - DOS386, 09.01.2008, 01:12
    • Qemu 0.9.1 is out ... :-( - sol, 09.01.2008, 01:30
      • Qemu 0.9.1 is out ... :-( - DOS386, 09.01.2008, 01:51
        • Qemu 0.9.1 is out ... :-( - sol, 09.01.2008, 02:55
      • keyboard problem in details - Japheth, 09.01.2008, 09:38
        • keyboard problem in details - jaybur, 09.01.2008, 13:13
          • keyboard problem in details - Japheth, 09.01.2008, 20:29
        • keyboard problem in details - sol, 09.01.2008, 17:15
  • Qemu 0.9.1 (Win32 binary download) - Rugxulo, 15.01.2008, 23:29
  • Qemu 0.9.1 is out ... - rr, 20.01.2008, 22:50
    • Qemu 0.9.1 is out ... - Japheth, 21.01.2008, 02:29