Re: Data General Nova 3 and 6045 Drive Questions

[Mark J. Blair]

> On Jun 12, 2016, at 20:55, Bruce Ray  wrote:
> 
> G'day Mark -
> 
> Brief notes...

Thanks!

> 4) 4075 TTY baudrate pretty easy to check; usually 4800 or 9600 baud, 7 data, 
> even parity, 1 stop bit.
I determined earlier today that I had merely had a brain fart regarding the 
strapping. The card was strapped for 4800, and I successfully reconfigured it 
for 9600.


> 6) 4046 disc controller board in slot 11 - wire-wrap wires seem to go from 
> slot 11 to edge connector.

Is there any specific reason you know of for the card to have been installed in 
slot 11 and requiring a laborious paddle board wiring job, rather than plugging 
it into slot 10 and using the P4 connector?

I am able to seek the drive heads, but can't seem to get any data or status 
back from it yet. I'm working on that assembler side project to make it easier 
to write up test programs to try out drive functions and debug things. I ran 
one of the memory checkerboard tests for quite a while without any apparent 
failures.


-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: Data General Nova 3 and 6045 Drive Questions

[Bruce Ray]

G'day Mark -

Brief notes...

1) DG part numbers are 005-xx-yy; 107-xx-yy numbers are circuit 
board artwork numbers.  Unfortunately, there is no standard 
cross-reference between the two.  Briefly, the part number is the 
primary reference to be used because a single 107-xx-yy circuit 
board may actually contain multiple 005-xx-yy parts.


The 005-xx-yy part number usually exists on a label attached to the 
15"x15" board stiffener (the side opposite the finger edge connectors).
Later DG boards also had an "A" number in addition to the product number 
("T"), so if both exist the "T 005-xx-yy" number determines the 
exact board function(s).



2) Slot 5 looks like it was also wired for a serial port board (4010 or 
4075) at one time since backplane pins A85 and B69 are wired to 
someplace in the backplane's paddleboard area.  But at this point the 
Interrupt priority and Data Channel priority daisy chains have been 
jumpered over the slot position to bypass the empty slot. (pins A93/A94, 
A95/A96)



3) One integral backplane edge connector may have a black "bus 
terminator" plug to reduce noise on the bus.  All DG terminators had a 
005- number on 'em for identification.



4) 4075 TTY baudrate pretty easy to check; usually 4800 or 9600 baud, 7 
data, even parity, 1 stop bit.



5) The 4060 board probably goes in slot 12 - wire-wrap wires go from 
slot 12 backplane pins to standard DG 4083 MUX connector distribution 
panel (the 16 row by 9 (+ 3) inline pins for each of the 4 serial ports 
plus 12 unused ports).



6) 4046 disc controller board in slot 11 - wire-wrap wires seem to go 
from slot 11 to edge connector.



Bruce

Re: Data General Nova 3 and 6045 Drive Questions

[Mark J. Blair]

Disk testing update:

I have the controller in slot 11 still, and the drive interface cable is 
connected to the edge paddle that appears to be wire-wrapped to slot 11. I 
haven't tried it in slot 10 using edge connector P4 yet, because I think I 
might need to fiddle with the two blue wires (bus grant? interrupt?) I see 
patched between the slots to do that, and I haven't studied what they do yet. 
Pictures of the backplane can be found on my blog:

http://www.nf6x.net/2016/06/data-general-nova-3-backplane/

Bootstrap from the drive channel still doesn't seem to work. The bootstrap 
loader does appear to be loaded into RAM, and the loader remains looping at 
000377, which never gets overwritten with a word from the drive channel.

Reading the drive status register always returns 0 so far. But, I do seem to be 
talking to the drive, because I think I can make it seek!

I cobbled together the following program and assembled it with Toby Thain's 
assembler found here:

http://www.telegraphics.com.au/sw/info/dpa.html


02  .TITL   dsktst1
03  .LOC0
05 0 062477 START:  IORST   ; Reset I/O channels
06 1 060633 DIAC0, DKP  ; Drive status register to AC0
07 2 065433 DIB 1, DKP  ; Drive mem addr register to AC1
08 3 072433 DIC 2, DKP  ; Drive disk addr register to 
AC2
09 4 034010 LDA 3, SEEK ; Load seek command to AC3
10 5 075133 DOAS3, DKP  ; Do seek
11 6 074433 POLL:   DIA 3, DKP  ; Poll drive status to AC3...
12 7 06 JMP POLL; ...forever
14 00010 003220 SEEK:   003220  ; Seek cyl 620(8):
15  ;   0  1 10 1001
16  ;   -> 0 000 011 010 010 000
17  .ENDSTART

This resets the I/O channel, reads the three drive registers into AC0-AC2, 
issues a near full seek command, then repeatedly polls the drive status 
register into AC0. I think. Running the program after a fresh drive load->ready 
sequence causes the drive to emit an audible clunk, so I believe that it is 
performing the seek! However, stopping the program and examining the 
accumulators shows that they all contain 0.

Incidentally, I see that the assembler I used assembles IORST as 062477, thus 
clearing the start and done flags. However, other sample programs I have seen 
show IORST as 062677, which issues a pulse instead of clearing start/done. I 
did not observe any difference in behavior in my test program when I tried both 
IORST varieties. Can any Nova experts chime in on any hidden gotchas that might 
lurk around this?

So, back to the task at hand: It seems that the CPU can talk to the drive, but 
maybe the drive can't talk back to the CPU? I think I'll work on bringing up a 
memory test next before I look at the hard drive some more.

BTW, the console is running at 4800 baud, while I expected it to be at 9600 
baud based on the strapping. That needs some more investigation, too.


-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/

Re: Data General Nova 3 and 6045 Drive Questions

[Mark J. Blair]

> On Jun 12, 2016, at 00:44, Henk Gooijen  wrote:
> 
> Just like Mark, it's about time to spend some time on my NOVA3.
> I will be following this with interest!

Yay!


> Were all bulbs on the front panel of your NOVA intact Mark?
> Or did/do you also have dead lamps?  Know of a source where to buy them?

I did have some dead bulbs. My memory is foggy, but I found some archived 
emails from when I discussed the bulb replacement two years ago. I think that I 
used number 2185 bulbs that I ordered from Digi-Key. Here are the old messages 
in my archive:


On Jun 14, 2014, at 09:21, Mark J. Blair  wrote:
> Do any of y'all know the bulb number for the fragile little wire-leaded bulbs 
> used in the Data General Nova's switch console? I have at least one burned 
> out, and a couple have snapped off. I measure about 15V across the bulbs on 
> my machine, but I don't know yet whether that's the correct voltage, nor do I 
> know the nominal voltage, current or brightness ratings of the correct bulbs.
> 
> Picture:
> 
> https://twitter.com/nf6x/status/477846674543362048/photo/1
> 



On Jun 15, 2014, at 09:06, Mark J. Blair  wrote:
> 
> On Jun 15, 2014, at 08:49 , Toby Thain  wrote:
>> Via email, snarfusmaximus writes, "I replaced mine with yellow LEDs with a 
>> series resistor."
> 
> That's a pretty tempting solution. Those original bulbs are quite fragile, 
> and appear to be quite prone to suffering lead breakage near the glass seal.
> 
> Here's what I just posted on VCF, for those (few?) folks who are here but not 
> there:
> 
>  8< cut here 8< 
> 
> Regarding the console bulbs, I found that one of mine that snapped off at the 
> base still has an intact filament. I was able to probe the wires at the glass 
> seals to light it up and measure current. The bulbs are normally powered from 
> an unregulated 14V rail as I understand things, and I measured the voltage at 
> around 15V on my machine. The broken-off bulb draws 39mA at 14V and the 
> filament color is quite orange. It draws 50mA at 28V and has a normal-looking 
> color temperature. I conclude that the original bulbs were probably designed 
> for 28V operation or so, and are used at lower voltage in the Nova 3 to 
> increase service life (?).
> 
> McMaster-Carr and Digi-Key both have some bulbs that look like possible 
> substitutes. I think I'll try some 2185 bulbs from Digi-Key since I'm 
> ordering other stuff from them anyway, unless anybody has a better confirmed 
> cross-ref. Those are 28V 40mA bulbs.
> 
> I also received an email from another collector who used KH 4-280-040A-1 
> bulbs from KH Lamp in his Nova. He reports that he got them from Swedish 
> distributor Elfa as part number 33-657-98. That's a 28V 40mA T1-1/4 bulb.


On Jun 15, 2014, at 14:16, Mark J. Blair  wrote:
> 
> 
> On Jun 15, 2014, at 12:51 , Brent Hilpert  wrote:
>> Here's another testimonial for a Nova, this fellow mentions replacing them 
>> with 28V/0.04A bulbs, but doesn't say how he knows those specs:
>>   http://www.foxdata.com/blog/?tag=nova-312
> 
> He's emailed me about his project. I can't access his web site at the moment, 
> and we're planning to look into that tomorrow.
> 
> 
>> The Hudson 2187D type he mentions maps to Chicago CM-2187, listed at Mouser:
>>   
>> http://ca.mouser.com/ProductDetail/Chicago-Miniature/2187/?qs=qp111mKzDjgelZXllf1Wrw==
> 
> Cool. If the 2185 bulbs that I'm ordering from Digi-Key don't work well, I'll 
> try some 2187 bulbs.

Re: Data General Nova 3 and 6045 Drive Questions

[Henk Gooijen]

-Oorspronkelijk bericht- 
From: Mark J. Blair

Sent: Sunday, June 12, 2016 8:32 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Data General Nova 3 and 6045 Drive Questions

Aha! Now I remember. That Cassette I/O card is mostly unpopulated, and I think it's just installed for its serial port. I think 
Bruce had told me about that long ago, but my memories are as dusty as the Nova is at the moment.

--
Mark J. Blair, NF6X <n...@nf6x.net>
http://www.nf6x.net/

-
Just like Mark, it's about time to spend some time on my NOVA3.
I will be following this with interest!

I have very little knowledge of it, Bruce is a great guy. Thanks again Bruce!
Even identifying the hardware was only possible with Bruce's help ...
My system has a 6070 disk drive, also a non-removable disk combined
with a removable cartridge. And when I got the system it also had a
model 6031 single 8" floppy drive. Later I was very lucky to pick up a
6025 tape drive (with tension arms, not vacuum columns). I even got the
controller board. I am still searching for the interconnection cable that
goes from the backplane to the circuit board attached to the tape drive.

Were all bulbs on the front panel of your NOVA intact Mark?
Or did/do you also have dead lamps?  Know of a source where to buy them?

- Henk, PA8PDP

Re: Data General Nova 3 and 6045 Drive Questions

[Mark J. Blair]

> On Jun 11, 2016, at 22:00, Bruce Ray  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 
http://www.nf6x.net/

Re: Data General Nova 3 and 6045 Drive Questions

[Bruce Ray]

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.


Contact me off-list regarding the documentation...

Bruce

On 6/11/2016 10:00 PM, Mark J. Blair wrote:

My Nova 3/12 system has a 6045 cartridge hard drive, with one fixed platter, 
one removable platter, and a capacity of 10M. I haven't managed to boot my 
computer from it yet, and after a long pause, my Nova 3 is requesting another 
time slice of my attention.

I can see in the drive's technical manual where I can specify surface 0-3 in 
the commands. I assume that the built-in bootstrap loader in the Nova 3 reads 
drive 0, cylinder 0, surface 0, sector 0, and places it at memory location 0, 
simply by virtue of all of the registers having been reset after an initial 
power-up and spin-up. The bootstrap loader code I've seen looks like it just 
issues a read command without initializing the memory address register and disc 
address/sector count register. I don't fully grok that code yet, so maybe I'm 
mistaken.

I have not found mention yet of which surface numbers correspond to the fixed 
platter and which correspond to the removable one. Is the removable platter 
selected as surfaces 0 and 1, such that the system would normally boot from the 
removable platter? Or would it normally boot from the fixed platter, with the 
removable platter being used to get data on and off the system?

Incidentally, I wonder if anybody has any original printed technical 
documentation relevant to my Nova 3 system which they might like to sell. I'm 
working off PDFs right now, and I'd like clean original paper copies for easier 
perusal and reference.

I'm also interested in replacing the filler panels in my Nova's rack with other 
interesting peripherals. Maybe a floppy drive? My 6045 is supposed to be able 
to be mixable with 6030 drives on the same bus, according to the 6045 manual. 
If anybody has some excess Nova hardware that might fit into my system, please 
let me know.

Data General Nova 3 and 6045 Drive Questions

[Mark J. Blair]

My Nova 3/12 system has a 6045 cartridge hard drive, with one fixed platter, 
one removable platter, and a capacity of 10M. I haven't managed to boot my 
computer from it yet, and after a long pause, my Nova 3 is requesting another 
time slice of my attention.

I can see in the drive's technical manual where I can specify surface 0-3 in 
the commands. I assume that the built-in bootstrap loader in the Nova 3 reads 
drive 0, cylinder 0, surface 0, sector 0, and places it at memory location 0, 
simply by virtue of all of the registers having been reset after an initial 
power-up and spin-up. The bootstrap loader code I've seen looks like it just 
issues a read command without initializing the memory address register and disc 
address/sector count register. I don't fully grok that code yet, so maybe I'm 
mistaken.

I have not found mention yet of which surface numbers correspond to the fixed 
platter and which correspond to the removable one. Is the removable platter 
selected as surfaces 0 and 1, such that the system would normally boot from the 
removable platter? Or would it normally boot from the fixed platter, with the 
removable platter being used to get data on and off the system?

Incidentally, I wonder if anybody has any original printed technical 
documentation relevant to my Nova 3 system which they might like to sell. I'm 
working off PDFs right now, and I'd like clean original paper copies for easier 
perusal and reference.

I'm also interested in replacing the filler panels in my Nova's rack with other 
interesting peripherals. Maybe a floppy drive? My 6045 is supposed to be able 
to be mixable with 6030 drives on the same bus, according to the 6045 manual. 
If anybody has some excess Nova hardware that might fit into my system, please 
let me know.

-- 
Mark J. Blair, NF6X 
http://www.nf6x.net/