IBM channel-attached DASD emulation

Guy Sotomayor ggs at
Fri Dec 25 22:16:02 CST 2015


On 12/25/15 5:55 PM, Mike Ross wrote:
> What about IBM channel-attached DASD?
> There are various CPUs lying around in private collections and museums
> - System/360s; System/370s; System/3 Model 15s; all used
> channel-attached DASD: and working reliable disks are much rarer than
> the damn CPUs!
It's typical of most of the vintage gear.  Folks save the CPUs and ditch 
the peripherals.
> Questions:
> 2. To those with hardware design experience: how big a task do you
> reckon it would be to do this as a home-brew with modern hardware -
> exactly as Dave did with his MFM emulator? Is it feasible? Do the
> entire thing in software - Pi or Arduino or FPGA - with appropriate
> driver electronics to drive a channel interface?
I've looked at this briefly.  I would expect that there will have to be 
more than just
software.  Talking with David re: MFM emulator, that was at about the 
limit of what
could be done with S/W.  Anything else would require at least *some* H/W.
> What do people reckon would be the best target for emulation? 3340
> springs to mind initially... would that work on machines as old as
> System/360s? It's about the *only* option for 5415 DASD...
 From my limited experience, I would think that any of the CCK drives 
would be
reasonable targets.  I think once you get one (3330?) the others should 
follow fairly
easily.  I think once you've emulated the controller, supporting the 
different drives
should be fairly straightforward.
> (To digress briefly - a modern reimplementation of something like the
> Setasi Massbus disk emulator would also be very useful; Rich - weren't
> LCM working on something like that?)
Again, I've looked at it.  I think the biggest problem is that there 
isn't a spec per-se
on Massbus.  A lot of reverse engineering will be required to make it 
work properly
in all cases.  It'll be a lot of reading (and fully understanding) the 
drive schematics and
then trying to generalize it.

TTFN - Guy

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