Re: [9fans] /sys/include/ip.h 5c(1)

[W B Hacker <wbh@conducive.org>]

lucio@proxima.alt.za wrote:
>>> but by 1990 with microchannel &c. things were much more closed off.
>> i thought only one company ever really made microchannel,
>> and even they weren't terribly in earnest in the end,
>> except on non-PC things like RS6000.
>
> IBM tried to recover control over the PC market by introducing MCA,
> bargaining that public sentiment would swing in their favour.

They might have had that in mind as a secondary reason - but I doubt even that.

The majority within IBM never wanted into that part of the market in the first
place, as it was seen as cannibalizing not only 3XXX terminal sales, but the
entire, highly profitable, big-iron+interface+network+services infrastructure
behind said terminals.

A more immediate need was for something better than ISA bus to meet the needs of
their mid-range servers - some of which would eventually grow - at least per the
manuals - to accomodate expansion trays with slots for over fifty cards (PCI at
that) - more than  double the actually usable max for ISA bus signalling,
moreover over a longer physical plan.

>  They
> could not have been more mistaken, one could easily call this the
> "Betamax error".  As soon as the other PC manufacturers of note (HP,
> Intel, Wang Labs, I forget who else)

Prime movers were HP and Compaq. Earliest small-fry (in those days) to deliver
to 'whomever' wanted a MB was Asus.

Novell Netware servers built on EISA to take advantage of duplexed fast SCSI
controllers and fiber-optic server-to-router TCNS 100 MBps (Arcnet)
interconnects plus 100 MBps TCNS over-coax to the ISA-bus workstations were in
their day rather serious ass-kickers - most especially with Microway add-in
'Number Smasher' CPU+FPU cards.

As is often the case, the link was - and remains - the bottleneck.

> released EISA

.. which, while far more welcome in the field, had slot-count / round-trip
timing limitations that made it technically inferior to MCA, and by a largish
margin, if one wanted a really high slot-count.

 > (which was quickly
> replaced by PCI),

Ditto, absent a 'bridge' chipset that was for a long time largely a DEC
controlled item AND NOT cheap.

Go see how many 'consumer' MB you can find with more than four
all-usable-at-once PCI slots. Hardly common even in 'server grade' MB.

Thankfully much has moved into on-planar silicon long-since, so less need.

> IBM's efforts were nullified.
>
> ++L
>
>

IBM is in many ways an anarchistic loose confederation of competing Divisions.

At sum, they are technically agnostic enough to simply 'follow the money'.

Feudal Microsoft, OTOH, want the money to follow *them*.

;-)

Bill