6 Jun
2023
6 Jun
'23
8:35 p.m.
In 1983 or 1984?, PC-World magazine ran an article
comparing compatability of
the clones. They "tested" based on which software would run, such as
"Flight
Simulator". They used version 1.00 of XenoCopy, which deliberately would
only run on real genuine IBM 5150 PC, although the versions of XenoCopy being
sold by that time would run on ANYTHING that had compatability with INT13h,
Int1Eh, Int10h, and had the text screen memory at B000h or B800h. They
referred to XenoCopy as "the acid test of compatability"
After that, and because of that, I wrote, but never bothered completing
debugging nor finished sufficiently for retail release, a program
intended to quantify compatability, called
"XenoPhobe : The Acid Test"
It started by identifying the processor. I could only do that by side
effects of obscure code, such as checking the size of the pre-fetch
buffer, the multi-segment over-ride issue, etc.
At one point, an article in MicroCornucopia discussed processor
identification, and mentioned "official Intel company internal methods".
I eventually found somebody at Intel who understood what I meant. He asked
that if I ever did find them, to send him a copy.
It did an attempt at speed test, and did some direct to memory video.
It checked Interrupt Vector Table for whether the BIOS interrupts pointed
to the same locations as IBM had, and checked some other location and ROM
specific items, such as the BASIC floating point accumulator.
It looked for IBM text strings in the ROMs, etc.
It was a fun diversion, but I did not think that it had any retail
potential. Certainly not enough to devote massive work towards doing it
right.
--
Grumpy Ol' Fred cisin(a)xenosoft.com