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Re: Unobtanium obtained!

 


On Feb 3, 2017, at 9:22 PM, Jack Rubin <j@...> wrote:

Who is best qualified to attempt to read these tapes and hopefully image the data on them?

I believe a 9875 should be useable to read the data off these tapes, and I think, also to create new tapes.  There are commands RF (read file), RR (read record), WF (write file), and WR (write record) that allows the transfer of arbitrary data words.  Sounds like incentive for me to get to figuring out the issue with my 9875 next so I can test it.

With a suitable binary program, it may be possible for a 85 A/B to also image these tapes if the tape controller uses the same low level encoding format, but I don’t know the answer to this.


Re: Unobtanium obtained!

Paul Berger
 

Wow nice find those tapes are indeed rare there is no complete copies known to exist.

Paul.


On 2017-02-04 12:22 AM, Jack Rubin wrote:

 I figure this is worth a new message topic. Today, I finally relocated 3 boxes of HP 80 series and 9825 items that got lost in storage during a move nearly 10 years ago. I haven't even gotten to the 85/87 stuff yet, but the 9825 box included a few data cartridges - three with user data and then:

** 09825-90035 - 9825A System Test Cartridge **

** 09885-90035 - 9825A/B 9885 System Tape Cartridge **

Also included was a 98015-66501 disk alignment fixture for the 9885 drives and a couple of 98032-085 disk interface cables.

I'm pretty sure I got all this stuff from Larry Lehman when he was shutting down Crisis Computers but at the time I was much more interested in the 2100 boxes and just sort of scooped these things up without paying much attention. Until I found them this afternoon, I didn't even remember getting them.

The tapes have been in cool, dry storage since I got them - I've never tried to use them and I certainly won't now!

Who is best qualified to attempt to read these tapes and hopefully image the data on them? I'll pose the same question directly to Al Kossow and Chuck Guzis but if the expertise is here, please let me know.


Jack




Unobtanium obtained!

Jack Rubin
 

 I figure this is worth a new message topic. Today, I finally relocated 3 boxes of HP 80 series and 9825 items that got lost in storage during a move nearly 10 years ago. I haven't even gotten to the 85/87 stuff yet, but the 9825 box included a few data cartridges - three with user data and then:

** 09825-90035 - 9825A System Test Cartridge **

** 09885-90035 - 9825A/B 9885 System Tape Cartridge **

Also included was a 98015-66501 disk alignment fixture for the 9885 drives and a couple of 98032-085 disk interface cables.

I'm pretty sure I got all this stuff from Larry Lehman when he was shutting down Crisis Computers but at the time I was much more interested in the 2100 boxes and just sort of scooped these things up without paying much attention. Until I found them this afternoon, I didn't even remember getting them.

The tapes have been in cool, dry storage since I got them - I've never tried to use them and I certainly won't now!

Who is best qualified to attempt to read these tapes and hopefully image the data on them? I'll pose the same question directly to Al Kossow and Chuck Guzis but if the expertise is here, please let me know.


Jack



Re: 9825 restoration notes and questions

 


On Feb 3, 2017, at 2:25 PM, Paul Berger <phb.hfx@...> wrote:

I don't think it is that big a deal I am half way there already with the rig I used to dump the ROMs.  The service manual talks about the signals the state machine monitors and what they mean.  the ROM feeds 6 bits into a an 8-1 multiplexer that select a bit based on the state of  A12, A13, and A14, in other word the 4K ROM provided a bit map of the the entire memory map from from 0 through 0x5FFF. 

Ok, good news.  Let me know if I can provide any information.  I’ll probably be ready to make an initial release of the base firmware and General I/O ROM disassembly outputs in a few days.

Looking at the code that is run for a ‘ldb’ (load binary from tape), there does not appear to be a check to see if a binary program would be large enough to overlap with any of the ROM address space, which would prevent a 9825T from executing it properly.  Binary programs are loaded so they end at 076547 in RAM.  Presumably HP assumed that since only they would be providing binary programs, they would know not to make them too large to cause conflicts with the address bit map on the A25 board.


Re: 9825 restoration notes and questions

Paul Berger
 



On 2017-02-03 4:41 PM, Craig Ruff wrote:

On Feb 3, 2017, at 1:34 PM, Paul Berger <phb.hfx@...> wrote:

Now that I think of it, it would be possible to verify the operation of the whole state machine on the A25 card using sometime to provide the appropriate input signals to the card since it is all static logic.

A big effort, as you would need to simulate instruction fetches at specific addresses  (including the instruction words for the state machine to decode the instruction type) along with the corresponding operand fetch(s).  Not impossible, but similar to just running the system.
I don't think it is that big a deal I am half way there already with the rig I used to dump the ROMs.  The service manual talks about the signals the state machine monitors and what they mean.  the ROM feeds 6 bits into a an 8-1 multiplexer that select a bit based on the state of  A12, A13, and A14, in other word the 4K ROM provided a bit map of the the entire memory map from from 0 through 0x5FFF. 

I can probably easily modify my disassembler to be able to identify the addresses of instructions that access RAM, which could then be used as a source of input data for such a stand alone verify operation.
Well in a T there is RAM from 0x400 to 0x7FFF, and ROM from 0 to 0x5FFF.  There is a gap of 2K words 0x5400 that does not seem to be used at this time however -CartOE is dropped for that address so there is potential for ROM to occupy that space.  There are also 1K word gaps at 0x3000 (Mass storage),  0x3C00 (Matrix) and 0x5C00 that may be occupied by plugin ROMs, but since there does not appear to be any way for the state machine to know if there are ROMs in that space or not, I would guess the state machine assumes there is.

Paul.


Re: 9825 restoration notes and questions

 


On Feb 3, 2017, at 1:34 PM, Paul Berger <phb.hfx@...> wrote:

Now that I think of it, it would be possible to verify the operation of the whole state machine on the A25 card using sometime to provide the appropriate input signals to the card since it is all static logic.

A big effort, as you would need to simulate instruction fetches at specific addresses  (including the instruction words for the state machine to decode the instruction type) along with the corresponding operand fetch(s).  Not impossible, but similar to just running the system.

I can probably easily modify my disassembler to be able to identify the addresses of instructions that access RAM, which could then be used as a source of input data for such a stand alone verify operation.


Re: 9825 restoration notes and questions

Paul Berger
 

Now that I think of it, it would be possible to verify the operation of the whole state machine on the A25 card using sometime to provide the appropriate input signals to the card since it is all static logic.

Paul.


Re: 9825 restoration notes and questions

Paul Berger
 

I just too a look at the schematic sheets for for the A24 and A25 cards with my scribbled notes.  The two cards are largely independent of each other, with only two signal from the A25 board that affect the A24 board.  Since you now say that the machine operates correctly without the A25 card, that would suggest that would verify function of 99% of the A24 board.  The two signals produced by the A25 board are OptMap and ROMSel.  The OptMap signal is pulled to ground by the A25 board this is inverted and is one input to a NAND gate (U49d) and the output is the C2 input top U48. When the A25 card is not installed the line is pulled high which in effect disables the system programming ROM and also turns off -CartOE for addresses 0x5400, 0x5800, and 0x5C00.  When the A25 card is present and ROMSel is active (high) the system programming ROM is active  at address 0x5000 and -CartOE will be active for addresses 0x5400, 0x5800 and 0x5C00.  Ox5C00 is where the second window to the 98228A ROM exists, the other two addresses appear to be unused.

ROMSel is an output from the state machine that inhibits the RAM and enables ROM.  The RAM on the A24 board is in the upper half of the memory maps, and the RAM on the A25 board is mapped into the lower half of the map, but has the first 2K disabled for space occupied by CPU registers, BasePage ROM and Compiler ROM. The 98228A also uses the area occupied by the BasePage ROM and Compiler ROM Tables for its bank selection mechanism since it is always occupied by ROM, and write to that space have no effect on the ROM.  The two cards independently determine when their RAM should be enabled.

Since the U29 ROM is connected to the demultiplexed  address bus, the contents could be dumped without removing the card you would just need to simulate enough of the bus to generate the addresses and the ALE signal to latch the address and the output of U29 could be captured using something like a logic analyzer.  

Always keep in mind that the MAD bus is NEGATIVE logic if you don't and you are trying to figure out the logic of anything connected to it you will quickly go down the garden path.


Paul.


On 2017-01-31 1:59 PM, Jack Rubin wrote:

Interesting - not much time to play around this morning before leaving for a few days, but I did find that with A25 in place and 64K selected, the system would note the presence/absence of the tape drive (i.e. error 43) if the Monitor Bus cable was _removed_. If the cable was in place, no error was reported whether the  tape drive was connected or not. Clearly _something_ is happening on A25 and the Monitor Bus cable is providing some signals. 

More tantalizing than conclusive. When I return home later in the week, I'll go ahead with a full physical tear-down and inspection of the other end of the Monitor Bus cable. 

More to come ...

_._,_._,_




Re: 9825 software availablity and more tape drive questions

Paul Berger
 

On 2017-02-03 1:13 PM, Jack Rubin wrote:

My 9825T seems to be working well as a 9825B even though the A25 board isn't fully functional. I've been able to enter and run programs and I can print to an attached 9866B printer.
I kind of expected it would function as a B from what your said before.

At this point, it seems that running system diagnostics would be very helpful so I'm looking next at repairing the tape drive and restoring some 3M DC100A tape cartridges with plastibands to allow some mass storage.

Is there a collection of 9825 software available, hopefully including images of the System Test and/or the Extended Test tapes?
As David Collins pointed out there is a tape image of the diagnostics at hpmuseum.net but it also notes it is not complete not sure how much use it would be without the missing binaries.

I was hoping to find some sort of standalone DC100A compatible drive that could be used with a desktop PC to write images to tape for use in 98XX machines but it seems that all the applications for these drives are integral to HP gear with the same drive problems! Is there a known DC100A-compatible tape drive?
I have never heard of any support for DC-100A outside of the HP desktop and a few pieces of test equipment. There is a standalone drive unit that connects via HPIB but I would doubt very much if there are drivers for it anywhere that would work with a PC.

Failing a non-HP application, I have a few HP 2644 terminals with dual drives that should be able to do stand-alone tape copies, once I've restored their drives and found reliable media.

Lots of chickens and no eggs (or maybe lots of eggs and no chickens).

Maybe it's time to start wire-wrapping a copy of Paul's 98228 ROM but that still begs the question of software availability.
You need to fix you A25 card before this would be useful, the 98228A is dependant on the A25 state machine because one window into the ROM overlaps the top 16K words of memory.

Paul.


Re: 9825 software availablity and more tape drive questions

 


On Feb 3, 2017, at 10:13 AM, Jack Rubin <j@...> wrote:

Is there a known DC100A-compatible tape drive?

The HP 9875 is a stand alone HP-IB DC100A drive.  However the one that I have isn’t fully functional yet.  When you give it a rewind command it places the tape on the opposite spool than the one the 85B and 9825T place it on.  I haven’t yet had time to resolve that issue, as I got distracted by my project to disassemble and annotate the 9825T firmware.

If I get my 9875 working, it should be usable to create 9825 compatible tapes with arbitrary content.


Re: 9825 software availablity and more tape drive questions

David Collins
 

Here's a link to 9825 system test software. 

http://www.hpmuseum.net/display_item.php?sw=294

David Collins
HP Computer Museum

Sent from out of the office


9825 software availablity and more tape drive questions

Jack Rubin
 

My 9825T seems to be working well as a 9825B even though the A25 board isn't fully functional. I've been able to enter and run programs and I can print to an attached 9866B printer. At this point, it seems that running system diagnostics would be very helpful so I'm looking next at repairing the tape drive and restoring some 3M DC100A tape cartridges with plastibands to allow some mass storage. 

Is there a collection of 9825 software available, hopefully including images of the System Test and/or the Extended Test tapes?

I was hoping to find some sort of standalone DC100A compatible drive that could be used with a desktop PC to write images to tape for use in 98XX machines but it seems that all the applications for these drives are integral to HP gear with the same drive problems! Is there a known DC100A-compatible tape drive?

Failing a non-HP application, I have a few HP 2644 terminals with dual drives that should be able to do stand-alone tape copies, once I've restored their drives and found reliable media.

Lots of chickens and no eggs (or maybe lots of eggs and no chickens). 

Maybe it's time to start wire-wrapping a copy of Paul's 98228 ROM but that still begs the question of software availability.

Jack


Re: 9825 restoration notes and questions

 


On Feb 2, 2017, at 4:15 PM, CuriousMarc <marc.verdiell@...> wrote:

Side question: is it so that you can then change a T that's configured for a '62 plotter to one that uses the '72 plotter by just flipping a switch? No need for an internal ROM change?

Exactly.


Re: 9825 restoration notes and questions

 

> if the A24 switch is set to select 64K memory and the '62 plotter, "list/execute" gives 31294 and with the '72 plotter selected, it gives 31260.

Side question: is it so that you can then change a T that's configured for a '62 plotter to one that uses the '72 plotter by just flipping a switch? No need for an internal ROM change?

Marc


Re: 9825 restoration notes and questions

 


On Jan 31, 2017, at 10:59 AM, Jack Rubin <j@...> wrote:

Clearly _something_ is happening on A25 and the Monitor Bus cable is providing some signals. 

At least the A25 board is on the top of the stack and easy to reach for attaching logic probes.


Re: 9825 restoration notes and questions

Paul Berger
 

Craig mentioned that error comes from the extended I/O, if the memory switch is in the 32K position when you remove the A25 card the extended I/O would not be available, this would suggest that the A25 card is participating with remapping the the ROMs.  This may indicate that the A25 is at least partially functional and the problem might be the RAM array on the card.

Paul.



On 2017-01-31 1:59 PM, Jack Rubin wrote:

Interesting - not much time to play around this morning before leaving for a few days, but I did find that with A25 in place and 64K selected, the system would note the presence/absence of the tape drive (i.e. error 43) if the Monitor Bus cable was _removed_. If the cable was in place, no error was reported whether the  tape drive was connected or not. Clearly _something_ is happening on A25 and the Monitor Bus cable is providing some signals. 

More tantalizing than conclusive. When I return home later in the week, I'll go ahead with a full physical tear-down and inspection of the other end of the Monitor Bus cable. 

More to come ...



Re: 9825 restoration notes and questions

Jack Rubin
 

Interesting - not much time to play around this morning before leaving for a few days, but I did find that with A25 in place and 64K selected, the system would note the presence/absence of the tape drive (i.e. error 43) if the Monitor Bus cable was _removed_. If the cable was in place, no error was reported whether the  tape drive was connected or not. Clearly _something_ is happening on A25 and the Monitor Bus cable is providing some signals. 

More tantalizing than conclusive. When I return home later in the week, I'll go ahead with a full physical tear-down and inspection of the other end of the Monitor Bus cable. 

More to come ...


Re: 9825 restoration notes and questions

 

For the tape drive error 43, this is caused by bits 3 (power off), 1 (servo failed), or 0 (unexpected BOT/EOT) of the tape controller's status register (R5) being set. These will be placed into bits 15, 13 or 12 of the ‘errwd’ (RAM base page word) by the ‘stsaf’ routine of the tape driver firmware.

At power up, the this will be caused by the probe of the tape drive during the implicit ‘ldp 0’ executed by the Extended I/O ROM at initialization time. Thus, if you see the error 43, that implies that the Extended I/O ROM is present and functional.


Re: 9825 restoration notes and questions

Jack Rubin
 

Craig and Paul,

Thanks to both of you for info and suggestions, especially your offers to swap boards for testing. 

I've got an HP LogicDart that makes it pretty easy to look around for pulsed input, so I'll use that tomorrow to try to find any activity on A25 that indicates the Monitor Bus cable is intact. I haven't yet actually pulled the processor assembly out of the case, so I'm still hoping that there may be a loose/bad/dirty connection that will be easy to resolve but I realize that may be unrealistic. 

I'll be able to put in a couple of hours tomorrow morning but then will be away for a couple of days. I'll post an update in the morning.

I have a scope and an older HP logic analyzer so I can also dig deeper if necessary, but without timing diagrams or a comparison board, I'm not too sure how far I'll be able to go.




Re: 9825 restoration notes and questions

 


On Jan 30, 2017, at 7:16 PM, Jack Rubin <j@...> wrote:

If the Monitor Bus connection is intact, I think I should find D2MapClk on pin 6 of U43 and DMapClk on pin 15 of the same chip. Does that make sense? Should the clocks should be 6MHz? 

I suspect that what Tony has labeled as DMapClk and D2MapClk may actually be the internal state signals from the BPC that indicate what type of memory access is being performed, and will not be periodic 6 MHz clocks, but dependent on what instructions are being executed at any point in time.

My logic programmer won’t read a 2332 ROM (i.e. U29), but I could rig up my 16500C or an ATMega to get the contents for comparison.

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