On 27/03/2024 07:09, Gerd Hoffmann wrote:
On Tue, Mar 26, 2024 at 01:30:48PM +0000, Mark Cave-Ayland wrote:
> Heh I've actually been using isapc over the past couple of weeks to fire up
> some old programs in a Windows 3 VM :)
I'm wondering why these use cases can't simply use the 'pc' machine
type?
The early pci chipsets of the 90-ies have been designed in a
backward-compatible manner, with devices such as the IDE controller
being mapped to the standard ISA ioports. So even an historic OS which
does not know what PCI is can run on that hardware, by simply talking to
devices using the standard ISA io ports ...
Hmmm that's a fair point: I think the pc machine has a PCI-ISA bridge included, so
ISA devices can be plugged in as needed. The reason I ended up on that configuration
was because I ended up chasing down a regression, and wanted to quickly eliminate
things such as ACPI.
ATB,
Mark.