DOS ain't dead

hot dos (Developers)

posted by kerravon , Sydney, Free World South, 08.05.2025, 00:24

When I run DOS 4.0 or Freedos under Virtualbox or qemu, it maxes out a CPU core (as far as I can tell).

Even though it is just sitting at the command prompt waiting for a keystroke.

Any idea what is causing that?

I would have expected the BIOS provided by Virtualbox/qemu to just ask the underlying host for a keystroke and that would put it to sleep.

I guess the timer interrupts will still be firing, but those too are internal to Virtualbox/qemu so I expect them to be small, even if it doesn't have the smarts to recognize that in this situation it doesn't need to run them at all.

Thanks. Paul.

Complete thread:

• hot dos - kerravon, 08.05.2025, 00:24 (Developers)
  • hot dos - ecm, 08.05.2025, 00:36
    • hot dos - kerravon, 08.05.2025, 01:25
      • hot dos - ecm, 08.05.2025, 10:42
        • hot dos - kerravon, 08.05.2025, 12:55
          • hot dos - ecm, 08.05.2025, 20:07
            • hot dos - kerravon, 08.05.2025, 23:21
              • hot dos - ecm, 09.05.2025, 01:16
                • hot dos - kerravon, 09.05.2025, 02:01
                  • hot dos - Ringding, 09.05.2025, 14:33
                    • hot dos - kerravon, 09.05.2025, 15:22
                      • hot dos - Ringding, 09.05.2025, 16:13
                        • hot dos - kerravon, 10.05.2025, 01:32
            • hot dos - kerravon, 13.05.2025, 09:04
          • hot dos - Ringding, 10.05.2025, 09:21
            • hot dos - kerravon, 10.05.2025, 14:40
              • hot dos - RayeR, 12.05.2025, 19:51
                • hot dos - kerravon, 12.05.2025, 23:02
  • hot dos - Rugxulo, 08.05.2025, 03:22
    • hot dos - kerravon, 08.05.2025, 07:24
  • hot dos - rmcconne, 11.05.2025, 15:15