[sebhc] Re: Re-creating actual floppies from archive

[Dan Lanciani]

|Core memory? I didn't know that existed for the H-8. Please elaborate.

It didn't exist specifically for the H8.  I bought two surplus 32K x 8
core planes and built my own interface, first on the prototype board and
later on the "wire-wrap" board but using solder.  I had to modify the
core boards so you could defer telling them whether you were reading or
writing until half way through the cycle.  (Normally they latched the
read/write line at the beginning of the cycle.)

Oddly, the core boards were very sensitive to interference.  Turning a
lamp on near them would corrupt a few bits.  (Maybe that's why they
were so cheap.)  When I switched to a Z80 the interface (which exploited
8080-specific timing signals) would have needed some significant changes
and probably could never have supported 0 wait state operation again, so
I switched to a 64K DRAM board whose price had by then come down to a
reasonable level.

I gave the core boards to a core collector years ago, but I still have
the interface.  I was thinking of stripping it to recover the wire-wrap
card.

				Dan Lanciani
				ddl at danlan.*com
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