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NCR DMV with Western Digital WD1001-05 ST506/MFM Board / Signetics 8x305 Controller

jonhales

Member
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Jun 3, 2014
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39
Location
UK
I have a 1982/84 NCR Decision Mate V (Five) in working order. That is, it boots from a floppy/gotek.

The base version uses a Z80 for CP/M-80 2.2. Among a variety of options were:
- an internal or external 8088 with which CP/M-86 and MS-DOS 2.11 were available
- an internal or external 10Mb ST-506/MFM hard drive.

My DMV has the 10Mb internal hard drive (an ST-412), which uses a 1982 WD1001-05 controller. The hard drive returns 'Not Ready' when accessed. Given that the two drives tested to date were functional when read with a David Gesswein 'MFM Emulator', I suspect there may be a fault with the WD1001-05 controller.

One reason for this suspicion is that there is a very incomplete install of MS-DOS on the ST412 drive. It's possible the controller may have failed at an early point in the install.

Here's a photo of the WD1001-05 board:

The WD1001 is well-documented. The hardware manual with schematics is on Bitsavers.org.

There are two initial steps that would be useful before deeper investigation:
- 'borrow' a WD1001 from another vintage system (early 1980s)
- replace the 50-pin socketed microcontroller on the board, a Signetics 8x305.

Can anyone help with information?
1. Which other systems used the WD1001-05 (or the WD1002-05 or WD1002-HD0)?

2. Which other systems used the 8x305 microcontroller?

Among the documentation of the DMV on oldcomputers.dyndns.org is a photo of the DMV's external (plug-in) hard drive interface. This shows a WD1002-HD0 controller board with a manufacture date of 1984. It seems possible that the WD1002 may have been fitted internally to DMV systems manufactured at a later date than mine.

Can anyone confirm whether the WD1002 is able to act as replacement for the WD1001?

With thanks in anticipation.
 

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Al Kossow

Documentation Wizard
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Sep 1, 2006
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If you should ever feel like desoldering the 82s181 parts I'd love to archive them.
As you can see on bitsavers, there were a couple of different versions of the 1001
all with different firmware.

There is actually someone currently working on a Motorola VME disk controller
for MAME that used the 8X305.

you can find some disassembled firmware here
https://github.com/brouhaha/wd100x
 
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rfka01

Experienced Member
Joined
Jan 10, 2012
Messages
67
Location
Bavaria
jonhales a complete NCR DOS 2.11 should have two floppy disks, grab the disk packs from https://www.retroprograms.com/NCRDMV/dmv2.html
To format your HD, use "config" to set your system's disk configuration, you can choose between two 5MB partitions or one 10MB partitions - the scheme is quite inflexible.
As a treat I've included an alternative DOS boot disk that has a fmt20-5 command, which allows you to format a 615-4-17 size harddisk (think 20MB Seagates) to 20MB.
The commands to partition and format in one go are "format c:" or "fmt20-5 c:" respectively.

If you want a dry run to see what should happen, MAME's DMV emulation is quite capable.

https://mega.nz/file/acoA0SpZ#HvVhAE...UiIBQvAOpSPx44

Robert

P.S. As for your controller woes, the bus adapters for the internal and external harddisk kits use the same components, if you can find a WD1005-HD0 (iirc it's used in the Kaypro 10 as well), you should be good to go. I think it's a better idea to try different harddisks on your controller first, however. The MFM emulator is more of a recovery solution, so even if a drive can be read with it, it's not a given it'll work on the original hardware.
 
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