7 Jun
2023
7 Jun
'23
12:20 a.m.
On Tue, 6 Jun 2023, Bill Degnan via cctalk wrote:
I thought the goal back then was not 100% hardware
compatibility, it was
MS/IBM DOS compatibility. To be able to load/run/copy files from one PC to
another, dBASE, Lotus, Wordstar, etc. I don't think most manufacturers
cared as long as the software worked and you could make a printout using a
standard printer of the day like an Epson or whatever.
Most people, even those who explicitly stated that it was, were not
intereste in 100% compatability, they just wanted something that would not
give them unexpected incompatabilities.
I tested all of my software on real IBM hardware. If it worked on the
real hardware, but failed on a customer's "compatible", it would be a
drag, but not the disaster that it would be if it had worked on my
"compatible", but failed on the real thing.
People who tested software on "compatible" machines sometimes got
surprised.
Trivial example: if the attribute of a text character is both reverse
video AND bright, the PC CGA handled that differently than the Columbia
CGA.
F'rinstance, one of my early versions worked on 5150, but failed on a
customer's AT&T 80186? machine. That was when I learned about the change
in the size of the prefetch buffer. The fact that it had worked on 5150
helped the customer to understand that it wasn't "BAD software", but that
it needed some tweaks to work with his "non-standard" machine. And
fortunately easily remedied (an otherwise unnecessary JMP to flush the
buffer) before the 5170 came out.
--
Grumpy Ol' Fred cisin(a)xenosoft.com