WD2010 update

[John McMillan]

In article <3247 at umn-d-ub.D.UMN.EDU> rhealey at ub.d.umn.edu (Rob Healey) writes:
>In article <113 at gizzmo.UUCP> mark at gizzmo.UUCP (mark hilliard) writes:
>>In article <1087 at cgh.UUCP> paul at cgh.UUCP (Paul Homchick) writes:
>>>In article <1990Feb20.234235.26713 at hybrid.UUCP> (Mark Dapoz) writes:
>>>In summary, I do not think it is true that you can plug replace a
>>>WD1010 with a WD2010 in all Unix-PCs. 
   ======        ======
>>This is true, the early .5meg boards in the 7300 and some of the 1 meg
>>7300's have external support to the chip which renders the upgrade
>>non-functional.
>
>	OK, next obvious question:
>
>	Can the external support be eliminated or altered so that the
>	2010[AB] can work with the board??

While we are discussing "obvious questions", I need a little
advice:
	I thought the principle difference between the WD1010 & WD2010
	was that the former has a ten-bit (0-1023) counter, while the
	latter has an eleven-bit (0-2047) counter.  Note: the counter
	is purely INTERNAL -- there are NO external differences here
	-- and all the counter does is wiggle its cute li'l strobe once
	for each step it increments or decrements -- ie., wants to move.
	The WD1010 and WD2010 are generally pin-compatible.

	I'd dearly like to be informed of the external support to the
	chip which "renders the upgrade non-functional".  There were
	a number of board changes over time... but I didn't see ANY
	changes in support of the WD1010 in the four schematics I
	SKIMMED, so I was probably too cursory.

While I'm awaiting Rob's disclosure, and while I'm awaiting
WD's call to explain the nuances differentiating the 'A and 'B
chips, I'll remind folks that previously all manner of
reports have been made regarding exchanges of WD1020 & WD2010
chips.  Quite possibly most of these stories contain truth, but
few ARE The Truth.

john mcmillan -- att!mtune!jcm -- muttering for SELF, not THEM