23 May
2020
23 May
'20
8:29 p.m.
On Sat, 23 May 2020, Boris Gimbarzevsky wrote:
Thanks for that really detailed review of
microprocessor history! A post to
save.
But, read carefully the corrections that others made!
Such as Noel pointing out that I was mistaken in assuming that there was a
direct progression in 4004 -> 8008 -> 8080,
and Liam's discussion of the Commodore BASIC.
I never had a Commodore 64. But, I had an MSD drive for a C64 connected
to an IEEE-488 board in a PC.
After your detailed discussion of the bizarre variety
of early Intel
microprocessors I now recall why I refused to have anything to do with PC's
in late 1980's.
Well, there were advantages and disadvantages.
The Motorola approach produced a better product.
BUT, it meant that software was delayed for new products. It took a while
before the good third party software showed up for the Mac.
OTOH, the Intel processors were a series of little steps, so it was
usually almost trivial to upgrade code to a new series of processors. It
took Micropro less than a week to port their 8080 CP/M Wordstar to the
8088 PC. It then took them much longer than that to prepare new manuals.
Some internal structures had patches on top of patches. Such as
Segment:Offset memory addressing, and figuring out that the PC FDC could
not do a DMA that straddled a physical (not Segment:Offset) 64K boundary,
although Int13h didn't realize it and have a suitable error message - some
later versions of DOS had occasional mysterious problems with FORMAT that
were easily solved by adding or removing TSRs to move the location of its
TPA.
I've never liked M$ software as it seems whenever
they produce a good
product, they dump it and come up with something far worse and stop
supporting the old one.
"Oh, but it is DANGEROUS to use a product past its [arbitrary, marketing
chosen] SELL-BY date."
> All of my knowledge of the following is third
hand, and probably mostly
> WRONG. If you are lucky, maybe some of the folk here who actually KNOW
> this stuff will step in and give the right information.
> Sequence is only approximate.
And, the REAL history is much more interesting AND WEIRDER than the
fictional variants.
--
Grumpy Ol' Fred cisin at xenosoft.com