29 Jul
2013
29 Jul
'13
3:29 p.m.
On Mon, Jul 29, 2013 at 3:38 PM, Geoffrey Oltmans <oltmansg at gmail.com> wrote:
From what I can tell, the DMA
restriction isn't too much of a problem in practical use, with the
exception of the serial port),
The PC Jr DMA restriction wasn't a problem with the serial port,
either, since normal PC serial ports don't use DMA. On a typical PC of
that time, DMA was only used by the disk controllers. It was added
for other things like sound cards around 1989 and ECP parallel ports
around 1992. Of course, there were other cards that used DMA, just
nothing very common.
The Wikipedia article erroneously claims that the lack of DMA affected
both the serial port and keyboard.