24 Sep
1997
24 Sep
'97
4:52 a.m.
On Wed, 24 Sep 1997, Jeff Kaneko wrote:
[Genuine IBM cards]
Two things come to mind here. The first is, that if memory serves,
not all of the cards in the original XT were made by IBM. I'm pretty
sure that 'Original' HD controllers were made by Xebec, for example.
Correct. And the drives were Tandon (floppies) and Seagate/Shugart ST412s
(hard disks). The original IBM PC/AT drive controller was a western
digitial.
Most of the other cards were (AFAIK) made by IBM, though.
I forget who made the 1/2 height floppy drives for the PC-jr and the
portable. The Portable monitor was a Zenith, and I think the MDA and CGA
monitors were also built by another company. Ditto some of the PSUs.
I feel like saying that 'original IBM' means 'as described in the
TechRef'. The only problem with that is that the hard disk controller
found in most UK XTs is totally different to the one shown in the O&A
TechRef, alas.
The other is, that in other things generally considered "collectible"
(such as automobiles, for example) it is considered acceptable to
have some non-original equipment installed, provided it is correct
for the period (and that the added stuff in of itself is historic).
But I think this only holds to a point: the system board and power
supply would probly best kept 'stock', but one of those Quadram 8086
add in boards would be definitely cool, for instance.
Agreed. Things like that 8086 card (where IBM _didn't_ make an equivalent)
are interesting cards and should certainly be kept.
But if we stick to CGA cards for a moment, if I was buying one at a radio
rally, or was buying one in a system, my order of preference would be :
1) Genuine IBM, as described in the TechRef
2) Close chip-wise clone (say with 4416 RAMs, not 4816's)
3) Near chip-wise clone, with some of the logic in PALs
4) ASIC design (I'd probably not bother with this).
It's a personal thing. I like to be able to stick a logic probe on the
card and see what's happening. That's something I can't do with a modern
machine, and that's one reason I collect some of these classics. YMMV and
all that.
Jeff
-tony