27 Sep
2005
27 Sep
'05
9:55 p.m.
Tony Duell wrote:
While it is rare that a minor error will surface in, say, the CPU (I have NEVER
seen a CPU go gradually, like "whoops, now I can't ADD or SHL" -- it's
all or
nothing), the diagnostics run in something like 1K of ROM with no memory use
other than video so they are helpful in diagnosing RAM problems. And the
sound, joystick, video, and floppy drive tests are helpful in determining if
the machine is functional on a basic level -- I always run them on any new PCjr
I come across to determine if it's worth hauling away or not :-)
--
Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/
Want to help an ambitious games project? http://www.mobygames.com/
Or check out some trippy MindCandy at http://www.mindcandydvd.com/
IIRC, a PS/2
model 25 and 30 also have BASIC in ROM. And a PCjr most certainly
does (along with a full diagnostic program and "keyboard tutorial" -- the diags
were impressive for the time).
The problem with those diagnostics (and most built-in diagnostics) is
that a fairly large part of the machine has to be operational (at least
the CPU, some memory, ROM, video) for them to be at all useful.