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 [email protected]
