On Mon, Jan 19, 2004 at 10:26:32PM -0500, Christian Fandt wrote:
> >And, if I did manage to create a realiable IDE interface, would anyone
> >else want one?
>
> Yes!
And me!
> Also Qbus would be of very strong interest too. I have at least two Unibus
> and four or perhaps five Qbus machines which would be targets of an IDE
> interface.
>
> >(I realize cost would be the overriding factor - believe it or not on
> >small runs like I do the PCB is by far the most expensive part)
I used to build Qbus and Unibus (and VAXBI!) boards at Software Results
Corp. ISTR we spent >$100 per Qbus blank board because we never made orders
larger than q. 100. They are large boards (by today's standards) and with
that much gold, aren't cheap to make.
Here's a suggestion: lay out the board with the bus drivers (and grants)
for *both* Qbus _and_ Unibus, and only populate the variety you wish to
make. At least that way, you'd have a chance to boost the quantity of
boards made, and bring down the price a little.
For me, at least, the hard part of designing a modern Qbus and/or Unibus
interface would be what to select for bus drivers. I happen to have a
small handful of real DEC Qbus chips (from my Q-BOARD days), and a large
quantity of 8641 chips. It's choosing the other stuff that gets hard.
It's not so bad in a small backplane, but if you use your Unibus boxes
like we used to (11/750 w/internal DD11DK + BA-11 + 3 x DD11DK...),
adhering to the spec becomes important.
-ethan
--
Ethan Dicks, A-130-S Current South Pole Weather at 20-Jan-2004 04:20 Z
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Ethan.Dicks_at_amanda.spole.gov http://penguincentral.com/penguincentral.html
Received on Mon Jan 19 2004 - 22:45:20 GMT