Tony Duell wrote:
I'm kind of surprised that this hasn't come up yet.
The original BIOS and the 2nd revision BIOS (Oct 1981) both had a cute
little bug in them where they would only count up to 544K of installed
memory. You might have 640K and have all of the switches set correctly,
but the BIOS bug caused the count to stop at 544KB.
What is the casue of this bug?
-tony
I'm confused. It's a bug!
What I'm asking is 'what changed between the buggy BIOS and the later,
correct one?; (in respect of this memory checking routine, of course). In
other words was it just a change of some constnnt (in which case the
original _spec_ could have been for 544K), was it a constant that was
mis-interprtedded (one infamous example of this is in the early PC BIS
serial routine where a constat is taken as 80 _decimal_ (50h) and not
80h, which means the status bits returned are nonsense!), was it a change
in logic, or what?
-tony