On 12.03.2011 21:44, Zbigniew B. wrote:
> I read, that the source of CPU (over)heating problems under original
> MS/PC-DOS was the fact, that its "waiting for key"-loop (or however it
> is called) didn't set CPU idle, when user (or application) was idle.

You need a driver for that, it is not standard part of normal DOS.

> For example: when the computer has been left with the cursor blinking
> in the command line.
> I'm wondering, whether this misfeature has been fixed in FreeDOS?

Yes! The good news is that newer FreeDOS kernels even have a simple
version built into the kernel itself. You can activate it by putting


in your (fd)config.sys file. The value 1 means normal, 0 means do not
put the CPU to idle, 2 and 3 activate some Win3 related extensions.

However, the normal way to let the CPU idle while DOS is idle is to
load a suitable driver or TSR. In MS DOS you would use POWER but in
FreeDOS you use the similar FDAPM tool. To load and activate it, run


either at the command prompt or in your autoexec or similar :-) The
FDAPM method needs only a bit of RAM and is more efficient than the
simple method built into the kernel. Its best to activate only one.

Regards, Eric

PS: You can also use FDAPM to ACPI throttle your CPU if your board
supports that. I once measured one board and found that throttling
meant "stop CPU during N of each 8 timeslices of 1/32768 second".
Can be useful if your CPU is faster than needed, e.g. for games...

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