Re: Architectural implications of locate mode I/O and channels

EricP <ThatWouldBeTelling@thevillage.com> writes:

Michael S wrote:

On Thu, 04 Jul 2024 13:33:36 -0400
EricP <ThatWouldBeTelling@thevillage.com> wrote:

This was back just after the "bus wars" era where many big players
were trying to grab control of the PC market with their proprietary
(and patented) next generation bus. PCI was hoped to resolve this
and provide that standard, open market, but failed because it didn't
address what card suppliers and customers wanted.
>

PCI didn't fail. It was a stunniing success.
With emergence of PCI anything else either died at spot (IBM
Microchannel, Compaq-backed EISA) or became tiny high-cost niche (VME
and off-springs).

>
Also vying for attention in the wars were Multibus I & II (pushed by Intel),
Futurebus (pushed by DEC), IIRC Apple had its own derivative of Futurebus
but different (of course) so you had to buy Apple devices,
NuBus, FASTBUS, Q-Bus.
>
PCI failed from the view that it was supposed to replace the 16-bit ISA
bus on PC's, but because of PCI card cost customers demanded that
motherboards continue to support ISA. Also plug-n-play made ISA board
support a lot easier. Motherboards had at least to support AGP,
the PCI variant for graphics cards so they couldn't eliminate PCI.
So PC motherboards and device manufacturers wound up supporting both.
Not what anyone planned or wanted.
>
Where PCI succeeded I suppose is, as you point out, outside the PC market
it killed off all the others. But that left those systems tied to the
higher cost cards, increasing their cost relative to PC's.

My recollection is that ISA hung on for a while to support the ISA cards
we already had.  As the old cards went out of service demand for ISA
support went with them.