Re: No 100 HZ timer !

Maciej W. Rozycki
2001-04-12T10:11:16Z

On Wed, 11 Apr 2001, Jamie Lokier wrote:

> Think of the original 64k and 256k VGA cards. I think some of those
> didn't have an irq, but did have a way to read the progress of the
> raster, which you could PLL to using timer interrupts. Some video games
> still look fine at 320x200 :-)

The *original* VGA, i.e. the PS/2 one, did have an IRQ, IIRC (according
to docs -- I haven't ever seen one). Cheap clones might have lacked it,
though.

Then there is workstation (non-PC) hardware from early '90s which we run
on and which uses an IRQ-driven interface to graphics adapters -- not only
for vsync.

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +