Pedisk1? (Was: Re: Commodore PLC TIB DD-001 / Drive 2001)

After all this discussion, I wonder...


On Sonntag, 20. Mai 2018 17:38:47 CEST Steve Gray wrote:
> Perhaps you are referring to the PEDISK-II
> clone:http://www.6502.org/users/sjgray/projects/pedisk2/index.html

I have a floppy disk controller I got on an aution a while ago, although due to 
my current time constraints and priorities I did not have time to further look 
at.

It is from COMPUTHINK (it says so on the back), some other texts on the board 
read: "FAB 5000120-000" and "DD DSK CTL P2", "ASSY 1000176".
Hand written there is the number "401614" (serial#?)

It has a 1791 disk controller chip on it ("FD1791-B01"), one TTL IC is 
unfortunately missing, but everything is socketed.
Three power regulators, +5V, +12V, -5V. It seems to plug into the two 
expansion connectors on the PET although I think the layout is wrong, as both 
(single-line!) are aligned with each other, not displaced/shifted as in the 
later dynamic/universal PETs.

It has a 2x25 card edge connector socket (similar to the expansion port on the 
C64 side), a 2x17 pin header connector (for the drive I guess, no key pin 
though), 8k RAM (8x MM5298 8192x1 dRAM).
There is no ROM/EPROM(!) although it comes with an adapter that seems to plug 
into a ROM socket to get some of the signals (maybe $9xxx/$Axxx memory 
window).

Ah, finally found it: http://www.nightfallcrew.com/wp-content/gallery/
commodore-cbm-8032-hp-early-version-1980-computhink-disk-drive-controller-
external-dual-disk-drive-woltron-rom-bus-adapter/20180202_122524.jpg
Not exactly the same (there _are_ layout differences to my board, e.g. on the 
left there are two single-line 1x20 pin headers, one above the RAM, one 
between the RAM and the card edge socket, where nightfall's version has the 
ASSY number)

The small IC to the lower left of the disk controller is missing in my board. 
As I cannot see a PROM mentioned on the page on my board, that is probably 
what is missing?

My assumptions are:
1) this is NOT the Pedisk2 original, right, but something else? Maybe this is 
an original Pedisk(1) (if there was a 2, there should be a 1, right...?)
2) What disk drives can I use this with? Standard shugart floppies, maybe with 
an adapted cable? 
3) how far is software compatibility between FD1791/1793 or even WD1771 (note 
the WD, which is a later model than the FD1771 what was a predecessor to 1791)

Many thanks in advance!
André