26 Apr
2008
26 Apr
'08
2:02 p.m.
Y'all need to re-read my post a couple of days ago. BIOS was there
mainly for ROM/Cassette BASIC (the *only* PC to do that). The
original choice for OS was CPM, but that story has been well told.
Although I wonder how many people realize the inside joke of one of
the BASIC demo programs? And who says IBM doesn't have a sense of
humor?
On Apr 26, 2008, at 12:55 PM, Tony Duell wrote:
That's not
the first time you've mentioned that, so now I have to ask
you: What's the #1 most glaring misdesign you can remember about the
5150 or 5160?
Oh, that's easy. The edge-triggered active high interrupts.
And on the software side, the fact that the BIOS serial port routines
don't use interrupts, making it necessary ot hit the hardware
directly if
you wanted any decent data rate without dropping characters. You
know, I
was under the impression that the whole point of device driver
routines
was so you could make different physical hardware look the same to the
applicaiton programs.
-tony