Unibus disk controller with modern storage

David Bridgham dab at froghouse.org
Thu Oct 20 15:55:33 CDT 2016

> Oh that blinkenlights panel is excellent! All emulators should have
> one! :-) 

Yeah, isn't that fun?  Once I got it running, I just sat and watched it
for about fifteen minutes while it ran our disk exercising program.  And
then I noticed a bug.  It apparently wasn't causing a problem but the
address line 00 was lighting up each time it did a DMA.  That didn't
seem right.  I looked through the Verilog and figured out what was going
on.  It probably wouldn't have caused a problem, maybe, but I got to fix
it anyway.  See?  'Dem blinkenlights are useful!

> I'm not really into Qbus much but would probably buy a
> production example anyway. I'd certainly fork out for several Unibus
> devices if you make them!

Our plan was to do a Unibus version of the same thing as a follow-on. 
It ought to be reasonably straightforward.
> One tip from someone with same issue in a parallel endeavor (IBM
> System/360 panel): they look much better and more authentic with 'warm
> white' LEDs. These are the ones I'm using:
> https://octopart.com/l5-n55n-fuv-sloanled-29855005

Yeah.  You can see in this picture that the LEDs I picked have this
yellow lens.  I was hoping that would warm up the output but obviously
it didn't.  I looked through the list of 1206 and 0805 LEDs on DigiKey
and didn't find any that were obviously what I wanted.  I'll take
suggestions from anyone.  Or, I suppose, I could re-spin the board for
through-hole LEDs.  I've actually come to prefer surface-mount though
and I'm hoping that one of these days I'll have my own pick and place
machine (or I'll talk our soon to exist MakerSpace into getting one).


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