[vcf-midatlantic] Zilog System 8000

[Jonathan Gevaryahu]

On 11/16/2015 4:16 PM, Evan Koblentz via vcf-midatlantic wrote:
>>> I hope that it is ok that I signed on to your list. I am from germany
> Welcome!
>
>>> and I'm looking for information about the Zilog System 8000. I know that you owned at least one in the past. I don't know if you still have it, but I hope so :)
> We have it, but we haven't done much with it. Perhaps at our next repair event. We have workshops here every few months.
>
Note I've been told QIC tapes of this age most likely (95% chance) have 
to be "baked" to prevent them from turning to mush against the drive 
heads. (I'm not 100% sure how the baking process is gone about, but I 
believe it requires disassembling the cartridge and removing the tape 
spool, and wrapping the tape around a special metal spindle, then 
heating it to a certain temperature for a few hours. I could be way off 
here.)

Also, to recover the data from these tapes, given the drive capstans 
(and cartridge capstans?) always seem to turn to goo and we're not sure 
if the z80-based interface card works or not...
Would it make more sense to get any old QIC drive that is sufficiently 
old enough to be hackable but has intact rollers, and (after baking the 
tapes) use an FPGA development board and some breadboarded analog 
amplifier magic to directly control the QIC motor and tap the QIC drive 
heads for the 4 tracks, and either record them as analog waveforms at a 
high samplerate, or log time-deltas (in 50mhz clocks) between flux 
transitions? Then decode the resulting flux stream entirely in software. 
50mhz may be extreme overkill, its possible digital sampling at 192khz 
or twice that may be fast enough, I don't really know...

I could have sworn someone on this list, or in another similar list 
(classiccmp?) had already worked out a setup for decoding tapes just 
like this...

-- 
Jonathan Gevaryahu
jgevaryahu at gmail.com
jgevaryahu at hotmail.com