--- Roger Ivie <IVIE_at_cc.usu.edu> wrote:
> Aha! Another VAXBI survivor!
And I've got the mounds of leftover crap to prove it!
> The company I used to work for did a quad IEEE-488 interface...
What an odd thing to make. That's a *lot* of instruments in a small amount
of space (owing to cable-length limitations).
> ...(imagine a Z80 looking up user-space addresses
> in the page table. Fun!)
Our drivers were a little different - first, all of our products were 68000-
based. Second, we used 1/4th of the address space as shared memory to the
VAX as a DMA cycle. Imagine this if you will... accessing 18 or 22 bits of
68K address space would return (or modify) the contents of a real physical
memory location in the VAX. I have used one of our Qbus boards and a Fluke
ICE tester to check LSI-11 DRAM chips... It works something like this...
o Plug into a BA11-N an 11/03 CPU with a row of 4096 DRAMs socketed, a
DL11-E, a COMBOARD-Q with the CPU removed and the Fluke plugged into
the CPU socket.
o Power on the BA11-N, then use ODT to flip a bit in the COMBOARD-Q CSR to
enable DMA cycles (safety measure on our part)
o Set up the Fluke to test 4K of memory in the "shared memory" quadrant of
the 68K address space.
o Check the results.
I used this arrangement to test 4Kx1 DRAMs for my Z-80-based GORF machine. I
have a DRAM tester for 64K and 256K chips, but it only tests single-supply
parts.
> We sold about a hundred or so IEEE-488 interfaces.
As far as I'm concerned, 100 is a handful. My old company made more than ten
times as many Unibus cards as that.
I think I get one inquiry per year about our old sync products; nothing
serious. Who needs to move sync data over 3780, HASP or SNA to or from
a VAX these days that doesn't already have a way to do it?
-ethan
=====
Infinet has been sold. The domain is going away in February.
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Received on Sat Dec 04 1999 - 01:34:32 GMT