21 Jun
2006
21 Jun
'06
6:25 p.m.
Chuck Guzis wrote:
IIRC, the Peanut also has no DMA controller and a
rather miserly PSU. In
comparison to the "clone XTs", it was actually pretty expensive for what it
offered. It could be that IBM never fully anticipated the stiff
competition from the Asian clone builders.
I forgot the lack of DMA, but it is more of a nuisance than a serious
design flaw. When using an OS like DOS the lack of DMA just made disk
access a little slower, as DMA could move memory to and from the floppy
disk faster than a processor loop could.
A bigger shortcoming that I should have mentioned was having the
keyboard using the NMI interrupt instead of IRQ1. I forget the exact
reason for this, but it resulted in a lot of lost keystrokes an annoying
beeps.
The original power supply was 33 watts, which was enough for a 128K
single floppy system with maybe a sidecar or two. The power supply was
later upgraded to 45 watts. And of course, to power the ridiculous
sidecars there was a power supply sidecar as well.
IBM never considered other things as competition back then .. Compared
to the 64 or other 'home machines', it was very expensive, but also very
capable. Compared to the PC, it was inexpensive and 'good enough'.
Compared to cheap PC or XT clones, it was a hard sell.