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Morrow M20 with Memorex 102 20MB Hard Drive Interface to S-100?

Soupwizard

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So I have this Morrow M20 case, inside is a Memorex 102 20MB (afaik) hard drive. It has 8" platters, a brown transparent cover over the drive platters, and probably sounds really cool when running. I was glad to see that the heads are in the locked position for shipping, so hopefully it still works. Will need to test out the power supply first.

Does anyone know what kind of interface it has? How can I get this to work on my Imsai? I found a product brochure online (here) that says it is compatible with the SA4000 interface - is that SASI?

More photos in this link: Photos of memorex 102 hard drive

memorex-102-0b.jpg
 

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From my recollection, the 102 uses the standard Shugart SA-1000 interface. Very similar to the ST506 interface; I suspect it might be possible to adapt the SA-1000 interface to and ST-506 interface with little more than some wiring.
 
A-100 Controller Board

A-100 Controller Board

Quite interesting board. As best I can tell all the hardware is standard TTL IC's (except the 9638's and 9613's, also common).
I actually have an SA1000 Seagate 8” HD with a similar transparent cover. I have for a long time been on the lookout for an XCOMP S-100 Controller board to run the drive. See for example:-
http://s100computers.com/Hardware Folder/XComp/Hard Disk Controller/XCOMP.htm
(Cannot justify it other than I would like to actually see the disk spinning and heads move!).

I have the XCOMP ST506 5” HD board BTW, works great. If I cannot find the 8" XCOMP board perhaps one day I will get around to doing an 8” HD S-100 Controller. It seems there is enough software in the Morrow manual to get started. I don’t for example see any PAL’s. Would others be interested?
 
I think the Morrow 8" hard drive and some versions of the Shugart SA1000 should work with a Compupro Disk2/Selector Channel Board Set.

I have several new and used Disk2/Selector hannel Board Sets in stock.

The challenge would be the code to operate the drive. Early versions of the Compupro CPM-80 and CPM-86 have support for the Disk2/Selector Channel Board Set with a loader coming in off 8" floppy (controlled by a Compupro Disk1 floppy drive controller board). Unassembled, commented code was on the Master Disks, and some early code was printed in the CPM and Disk2 technical manuals.
 
Just looked at the Disk2/Selector Channel Board set. Two boards to access a hard disk is a high price (for me at least). I think at least for a SA1000 it could be done with one S-100 board. Also the Disk2 has two PAL's on it which is frustrating also since I don't see the equations in the manual.

However more problematic is the fact that is that the system is DMA driven. If you only wish to run CPM/Z80 etc. not a problem, but if you want several different CPU’s in the bus in a master/slave arrangement things get complicated because to use DMA with the slave you then either have to have a slave to the slave or pass control back to the (typically slow) Z80/master. Now as it turns out on our recent 80386 (see recent posting) board I allow the slave configuration to itself run DMA/sub-slave using two unused S-100 bus lines. However this is probably outside the range of many users and as best I can tell, not used on older S-100 CPU boards.

A much better way to do things on the S-100 bus is to communicate via I/O ports using either wait states to synchronize or have an onboard CPU (like the ZFDC board) and transfer sectors with handshaking. That I how I would do it. I’m just a bit concerned with the hardware of stripping out the data clock signals etc. – analogue kind of stuff.
 
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