Data General Nova 3 and 6045 Drive Questions

Mark J. Blair nf6x at
Sun Jun 12 00:10:00 CDT 2016

> On Jun 11, 2016, at 22:00, Bruce Ray <Bruce at> wrote:
> DG Model 6045 disk drive heads 0 and 1 are the removable platter, heads 2 and 3 are the 'fixed' platter.  As you said, the controller memory address and sector/sector/count values are set to 0 by the IORESET pulse, so a read operation (STRT pulse) will start the reading of the bootstrap into low memory from the removable disk.

Excellent! That makes sense.

Ok, studying the documentation scans I have some more, I think I plugged the hard drive interface cable into the wrong connector when I reassembled the system after moving it. Hopefully I didn't damage anything! On the backplane, there's a terminator on the bottom rear connector (P3 I/O bus, I think), and there's another card edge installed behind the top rear connector (P4, disk drive interface, I think). I had the disk drive cable on the inboard add-on connector instead of the top backplane connector (P4). I think that was wrong!

But studying the documentation, I see that P4 is hard-wired to slot 10. However, the cards might be installed incorrectly in my system. I have plugged in:

  Slot |  Part Number  | Description
    12 | 107-000116-08 | DGC NOVA QUAD MULTIPLEXER
    11 | 107-000187-16 | DISK CARTRIDGE CONTROL DGC NOVA
    10 |               | 
     9 |               | 
     8 |               | 
     7 |               | 
     6 |               | 
     5 |               | 
     4 | 107-000151-19 | DGC NOVA CASSETTE I/O
     3 |               | 128K MOSTEK MEMORY
     2 | 107-000621-01 | NOVA 3 TRIPLE OPTION
     1 | 107-000539-05 | NOVA 3 CPU

I think that I need to both move the hard drive cable to P4 at the top rear of the backplane, and move the disk controller card to slot 10. Does that sound correct?

I don't know what that expansion card edge is for yet, and I can't get to it easily right now with the chassis in the rack. Maybe it's wired to the Cassette I/O card? I should take some detailed pictures to post and discuss tomorrow.

That Cassette I/O card looks interesting to me, and I wonder if there's any chance that I might find the tape transport that goes with it.

> Contact me off-list regarding the documentation...

Will do! And thanks for your indispensable help with my system last time I gave it some brain bandwidth.

Now I'm off to try and figure out what baud rate my console is strapped for, which I wasn't smart enough to write down last time I worked with the system.

Mark J. Blair, NF6X <nf6x at>

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