Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jack Harper via cctalk]

Hello Anders -

Sorry for the delay responding - I had a couple 
medical issues pop up that slowed me down a bit.


Yes, there are two photosensors on the Overland 
Data Tape Drive that detect BOT/EOT conditions from the shiny reflective strip.


I checked the voltages coming out of the photo 
detector thingus's and see +0.3 VDC with no strip 
and +3.0VDC with the reflective strip.


That seems OK to me - but, I have no schematic.

I believe from the parts placement on the board 
that the BOT/EOT signal path goes into an op-amp - probably.


Regards to the List from the Rocky MOuntains,

Jack







Hi Jack,

I believe finding the load point and 
bottom-of-tape has to do with photosensors that 
pick up reflected light from a lamp/photo 
detector assembly in the tape path. Are you 
sure the lamps are working? After that you'd 
look for the reflective sticker on the tape 
then perhaps scope the photo detectors.


=]

--
Anders Nelson

+1 (517) 775-6129

<http://www.erogear.com>www.erogear.com

On Thu, Oct 5, 2017 at 7:47 PM, Jack Harper via 
cctalk <<mailto:cctalk@classiccmp.org>cctalk@classiccmp.org> wrote:


Marc -
I certainly do know you from your great YouTube videos.
Because of the video on the Overland Data 
drive, I bought one of those that popped up on 
eBay, but it will not find load point.
The output voltages from the BOT sensor look, I 
think, good or at least reasonable:Â  +0.3VDC 
for the DARK condition and +3.0VDC for the LIGHT condition.
The drive failed all of the power-on 
diagnostics when I first got it, but I 
discovered how to re-initialize NOVRAM to 
"factory settings" by weird button pushes - Did that and all was well.


However, the drive will not, now, find the load point and so I am stuck.
That was interesting to me as you had the exact 
same problem with the 7970 on your YouTube video - burned out light bulb.
I believe the problem in the Overland to be 
something other than the BOT sensor.


I considered a SCSI tape drive, but really I 
want the classic open reels with the classic 
fast/stop action. Reliving, of course, my 
childhood when I grew up living inside a UNIVAC 
1108 - assembly and all that - and all those drives start/stopping :)
I consider this a long term project if I tackle 
it - clearly not something that I can dash together over a weekend.
Do you think that parity issue on commands is 
only for the HP-IB controller and not if I end 
up talking direct to the internal controller of 
the 7970 tape drive??  Any idea on that?


Regards to the List,
Jack



At 12:22 AM 10/4/2017, Curious Marc wrote:

Jack,
You can drive an HP-IB equipped HP7970E with an 
old PC that has an HP-IB card using Ansgar 
Kueckes HPDIR. I debugged it together with 
Ansgar. The rub is that it only worked well 
with an ISA HP-IB card running under Win98. The 
PCI HP-IB card running under XP uses a driver 
that causes timing errors and it skipped some 
records, and I don't think Ansgar ever bothered 
to fix it - we were happy enough to have made 
one solution work... The commands used to read 
and write from the tape are complex and tricky, 
and you have to get your timing right as there 
is hardly a buffer in the interface (128 
bytes). And there is this weird parity thing, 
where parity has to be generated for commands 
on the HPIB bus, but not for data, or something 
of that ilk. If not the tape just hangs the 
bus. There are several GPIB emulators based on 
Arduino that should enable you to build an interface.

You know me, I made several videos documenting the work on the 7970E tape:
< https://youtu.be/eCBxNhEzIfc?t=7m6s > 
https://youtu.be/eCBxNhEzIfc?t=7m6s (tape 
interfaced with a PC running Ansgar HPDIR)
< https://youtu.be/5J8IbpJoeqk > 
https://youtu.be/5J8IbpJoeqk (shows how I 
sniffed the HP-IB bus to figure out how the 
commands worked - or didn't, also has a demo of 
sending a rewind command in the raw via a paddled-in program)
< https://youtu.be/YS9dGYUbNd0 > 
https://youtu.be/YS9dGYUbNd0 (showing a demo 
with the tape attached to an HP-85, using an 
FPGA based gizmo to take care of the on-the-fly parity generation)
< https://youtu.be/rAsLwcq4RNU > 
https://youtu.be/rAsLwcq4RNU (fixing a loading fault on the tape drive)
Although I love the HP 7970E dearly and want to 
encourage you to try your luck at it, that was 
a lot of work to get it to work on something it 
wasn't meant for. You'd have a much easier time bringing up a SCSI based tape.

Marc

Subject: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive
Question:Â  Anyone have experience talking to a 7970 tape drive from
something other than an HP computer - something that does not have
HP-IB???  How is that usually done??
Jack Harper
Evergreen, Colorado



-- 


Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA
303.670.837

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[J. David Bryan via cctalk]

Marc,


On Sunday, October 8, 2017 at 11:48, CuriousMarc wrote:

> Thanks, I wasn't aware of this subtlety.

You're welcome.


> But this is for the 7970E only, right? 

Right.


> Can you boot a 21MX from a 7970B tape with the standard boot ROM? 

Yes.

The boot ROM data transfer loop is just a tiny bit too slow -- 14.26 usec 
worst case (i.e., with an intervening RAM refresh) -- for the 1600 bpi 
interface, which allows 13.9 usec before indicating a Timing Error.  The 
800 bpi interface allows double that time, which the ROM loop easily meets.

  -- Dave

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[CuriousMarc via cctalk]

Dave,
Thanks, I wasn't aware of this subtlety. But this is for the 7970E only,
right? Can you boot a 21MX from a 7970B tape with the standard boot ROM? Is
your better boot ROM code available?
Marc

-Original Message-
From: cctech [mailto:cctech-boun...@classiccmp.org] On Behalf Of J. David
Bryan via cctech
Sent: Friday, October 06, 2017 11:11 AM
To: Classic Computing List
Subject: RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape
Drive

On Tuesday, October 3, 2017 at 20:58, Jay West via cctalk wrote:

> Wasn't there some deal where a M/E/F could drive it at 45ips but a 
> 2100 couldn't (next lower speed)??

You might be thinking of the limitation regarding the use of the 12992D
Magnetic Tape Loader ROM with a 1000 M-Series and a 7970E (1600 bpi)
operating at 45 ips.  This bootstrap loader used skip-on-flag
(word-at-a-time) mode, and the data transfer loop could not keep up at tape
speeds greater than 37.5 ips.  The faster E- and F-Series CPUs could run the
bootstrap with the drive configured for the full 45 ips.

The 2100 and the 1000 M/E/F-Series machines had no such limitation if
DMA/DCPC was used to access the tape drive.  DMA wasn't used in the boot
loader ROM because the code wouldn't fit in the 64-word ROM size.

(That said, I've rewritten the 12992D bootstrap to tighten the timing loops,
and it works fine on my 1000 M-Series and 7970E drive.  I think the original
limitation was due to suboptimal coding.)

  -- Dave

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[emanuel stiebler via cctalk]

On 2017-10-05 17:37, Jack Harper via cctalk wrote:




I appreciate the description of your STM32F407 machine - makes sense and 
gives me hope that I can replicate the functionality in the 68K world.


What 68k machines do you have there, you like to attach to the 7970?
Cheers

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[CuriousMarc via cctalk]

Talking to the direct interface should be much easier interface-wise. The
added difficulty is that you are now responsible for formatting. The
interface is well documented (look for
5952-5441_HP_7970E_Interface_Guide_May71.pdf), at least for the E.

Marc

 

From: Jack Harper [mailto:har...@secureoutcomes.net] 
Sent: Thursday, October 05, 2017 4:47 PM
To: Curious Marc; cctalk@classiccmp.org
Subject: Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape
Drive

 



Marc -

I certainly do know you from your great YouTube videos.

Because of the video on the Overland Data drive, I bought one of those that
popped up on eBay, but it will not find load point.

The output voltages from the BOT sensor look, I think, good or at least
reasonable:  +0.3VDC for the DARK condition and +3.0VDC for the LIGHT
condition.  

The drive failed all of the power-on diagnostics when I first got it, but I
discovered how to re-initialize NOVRAM to "factory settings" by weird button
pushes - Did that and all was well.

However, the drive will not, now, find the load point and so I am stuck.

That was interesting to me as you had the exact same problem with the 7970
on your YouTube video - burned out light bulb. 

I believe the problem in the Overland to be something other than the BOT
sensor.


I considered a SCSI tape drive, but really I want the classic open reels
with the classic fast/stop action. Reliving, of course, my childhood when I
grew up living inside a UNIVAC 1108 - assembly and all that - and all those
drives start/stopping :)

I consider this a long term project if I tackle it - clearly not something
that I can dash together over a weekend.

Do you think that parity issue on commands is only for the HP-IB controller
and not if I end up talking direct to the internal controller of the 7970
tape drive??  Any idea on that?


Regards to the List,

Jack




At 12:22 AM 10/4/2017, Curious Marc wrote:



 
Jack,
 
You can drive an HP-IB equipped HP7970E with an old PC that has an HP-IB
card using Ansgar Kueckes HPDIR. I debugged it together with Ansgar. The rub
is that it only worked well with an ISA HP-IB card running under Win98. The
PCI HP-IB card running under XP uses a driver that causes timing errors and
it skipped some records, and I don't think Ansgar ever bothered to fix it -
we were happy enough to have made one solution work... The commands used to
read and write from the tape are complex and tricky, and you have to get
your timing right as there is hardly a buffer in the interface (128 bytes).
And there is this weird parity thing, where parity has to be generated for
commands on the HPIB bus, but not for data, or something of that ilk. If not
the tape just hangs the bus. There are several GPIB emulators based on
Arduino that should enable you to build an interface.
 
You know me, I made several videos documenting the work on the 7970E tape:
https://youtu.be/eCBxNhEzIfc?t=7m6s (tape interfaced with a PC running
Ansgar HPDIR)
https://youtu.be/5J8IbpJoeqk (shows how I sniffed the HP-IB bus to figure
out how the commands worked - or didn't, also has a demo of sending a rewind
command in the raw via a paddled-in program)
https://youtu.be/YS9dGYUbNd0 (showing a demo with the tape attached to an
HP-85, using an FPGA based gizmo to take care of the on-the-fly parity
generation)
https://youtu.be/rAsLwcq4RNU (fixing a loading fault on the tape drive)
 
Although I love the HP 7970E dearly and want to encourage you to try your
luck at it, that was a lot of work to get it to work on something it wasn't
meant for. You'd have a much easier time bringing up a SCSI based tape.
 
Marc
 

Subject: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive
 
Question:  Anyone have experience talking to a 7970 tape drive from 
something other than an HP computer - something that does not have 
HP-IB???  How is that usually done??
 
Jack Harper
Evergreen, Colorado
 
 


--
Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA

303.670.8375
303.670.3750 (fax)

http://www.secureoutcomes.net <http://www.secureoutcomes.net/>  for Product
Info.

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[J. David Bryan via cctalk]

On Tuesday, October 3, 2017 at 20:58, Jay West via cctalk wrote:

> Wasn't there some deal where a M/E/F could drive it at 45ips but a 2100
> couldn't (next lower speed)?? 

You might be thinking of the limitation regarding the use of the 12992D 
Magnetic Tape Loader ROM with a 1000 M-Series and a 7970E (1600 bpi) 
operating at 45 ips.  This bootstrap loader used skip-on-flag 
(word-at-a-time) mode, and the data transfer loop could not keep up at tape 
speeds greater than 37.5 ips.  The faster E- and F-Series CPUs could run 
the bootstrap with the drive configured for the full 45 ips.

The 2100 and the 1000 M/E/F-Series machines had no such limitation if 
DMA/DCPC was used to access the tape drive.  DMA wasn't used in the boot 
loader ROM because the code wouldn't fit in the 64-word ROM size.

(That said, I've rewritten the 12992D bootstrap to tighten the timing 
loops, and it works fine on my 1000 M-Series and 7970E drive.  I think the 
original limitation was due to suboptimal coding.)

  -- Dave

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Anders Nelson via cctalk]

Hi Jack,

I believe finding the load point and bottom-of-tape has to do with
photosensors that pick up reflected light from a lamp/photo detector
assembly in the tape path. Are you sure the lamps are working? After that
you'd look for the reflective sticker on the tape then perhaps scope the
photo detectors.

=]

--
Anders Nelson

+1 (517) 775-6129

www.erogear.com

On Thu, Oct 5, 2017 at 7:47 PM, Jack Harper via cctalk <
cctalk@classiccmp.org> wrote:

>
>
> Marc -
>
> I certainly do know you from your great YouTube videos.
>
> Because of the video on the Overland Data drive, I bought one of those
> that popped up on eBay, but it will not find load point.
>
> The output voltages from the BOT sensor look, I think, good or at least
> reasonable:  +0.3VDC for the DARK condition and +3.0VDC for the LIGHT
> condition.
>
> The drive failed all of the power-on diagnostics when I first got it, but
> I discovered how to re-initialize NOVRAM to "factory settings" by weird
> button pushes - Did that and all was well.
>
> However, the drive will not, now, find the load point and so I am stuck.
>
> That was interesting to me as you had the exact same problem with the 7970
> on your YouTube video - burned out light bulb.
>
> I believe the problem in the Overland to be something other than the BOT
> sensor.
>
>
> I considered a SCSI tape drive, but really I want the classic open reels
> with the classic fast/stop action. Reliving, of course, my childhood when I
> grew up living inside a UNIVAC 1108 - assembly and all that - and all those
> drives start/stopping :)
>
> I consider this a long term project if I tackle it - clearly not something
> that I can dash together over a weekend.
>
> Do you think that parity issue on commands is only for the HP-IB
> controller and not if I end up talking direct to the internal controller of
> the 7970 tape drive??  Any idea on that?
>
>
> Regards to the List,
>
> Jack
>
>
>
>
> At 12:22 AM 10/4/2017, Curious Marc wrote:
>
>>
>> Jack,
>>
>> You can drive an HP-IB equipped HP7970E with an old PC that has an HP-IB
>> card using Ansgar Kueckes HPDIR. I debugged it together with Ansgar. The
>> rub is that it only worked well with an ISA HP-IB card running under Win98.
>> The PCI HP-IB card running under XP uses a driver that causes timing errors
>> and it skipped some records, and I don't think Ansgar ever bothered to fix
>> it - we were happy enough to have made one solution work... The commands
>> used to read and write from the tape are complex and tricky, and you have
>> to get your timing right as there is hardly a buffer in the interface (128
>> bytes). And there is this weird parity thing, where parity has to be
>> generated for commands on the HPIB bus, but not for data, or something of
>> that ilk. If not the tape just hangs the bus. There are several GPIB
>> emulators based on Arduino that should enable you to build an interface.
>>
>> You know me, I made several videos documenting the work on the 7970E tape:
>> <https://youtu.be/eCBxNhEzIfc?t=7m6s>https://youtu.be/eCBxNhEzIfc?t=7m6s
>> (tape interfaced with a PC running Ansgar HPDIR)
>> <https://youtu.be/5J8IbpJoeqk>https://youtu.be/5J8IbpJoeqk (shows how I
>> sniffed the HP-IB bus to figure out how the commands worked - or didn't,
>> also has a demo of sending a rewind command in the raw via a paddled-in
>> program)
>> <https://youtu.be/YS9dGYUbNd0>https://youtu.be/YS9dGYUbNd0 (showing a
>> demo with the tape attached to an HP-85, using an FPGA based gizmo to take
>> care of the on-the-fly parity generation)
>> <https://youtu.be/rAsLwcq4RNU>https://youtu.be/rAsLwcq4RNU (fixing a
>> loading fault on the tape drive)
>>
>> Although I love the HP 7970E dearly and want to encourage you to try your
>> luck at it, that was a lot of work to get it to work on something it wasn't
>> meant for. You'd have a much easier time bringing up a SCSI based tape.
>>
>> Marc
>>
>>
>> Subject: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive
>>
>> Question:  Anyone have experience talking to a 7970 tape drive from
>> something other than an HP computer - something that does not have
>> HP-IB???  How is that usually done??
>>
>> Jack Harper
>> Evergreen, Colorado
>>
>>
>>
> 
> --
> Jack Harper, President
> Secure Outcomes Inc
> 2942 Evergreen Parkway, Suite 300
> Evergreen, Colorado 80439 USA
>
> 303.670.8375
> 303.670.3750 (fax)
>
> http://www.secureoutcomes.net for Product Info.
>

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jack Harper via cctalk]

Marc -

I certainly do know you from your great YouTube videos.

Because of the video on the Overland Data drive, I bought one of 
those that popped up on eBay, but it will not find load point.


The output voltages from the BOT sensor look, I think, good or at 
least reasonable:  +0.3VDC for the DARK condition and +3.0VDC for the 
LIGHT condition.


The drive failed all of the power-on diagnostics when I first got it, 
but I discovered how to re-initialize NOVRAM to "factory settings" by 
weird button pushes - Did that and all was well.


However, the drive will not, now, find the load point and so I am stuck.

That was interesting to me as you had the exact same problem with the 
7970 on your YouTube video - burned out light bulb.


I believe the problem in the Overland to be something other than the 
BOT sensor.



I considered a SCSI tape drive, but really I want the classic open 
reels with the classic fast/stop action. Reliving, of course, my 
childhood when I grew up living inside a UNIVAC 1108 - assembly and 
all that - and all those drives start/stopping :)


I consider this a long term project if I tackle it - clearly not 
something that I can dash together over a weekend.


Do you think that parity issue on commands is only for the HP-IB 
controller and not if I end up talking direct to the internal 
controller of the 7970 tape drive??  Any idea on that?



Regards to the List,

Jack




At 12:22 AM 10/4/2017, Curious Marc wrote:


Jack,

You can drive an HP-IB equipped HP7970E with an old PC that has an 
HP-IB card using Ansgar Kueckes HPDIR. I debugged it together with 
Ansgar. The rub is that it only worked well with an ISA HP-IB card 
running under Win98. The PCI HP-IB card running under XP uses a 
driver that causes timing errors and it skipped some records, and I 
don't think Ansgar ever bothered to fix it - we were happy enough to 
have made one solution work... The commands used to read and write 
from the tape are complex and tricky, and you have to get your 
timing right as there is hardly a buffer in the interface (128 
bytes). And there is this weird parity thing, where parity has to be 
generated for commands on the HPIB bus, but not for data, or 
something of that ilk. If not the tape just hangs the bus. There are 
several GPIB emulators based on Arduino that should enable you to 
build an interface.


You know me, I made several videos documenting the work on the 7970E tape:
<https://youtu.be/eCBxNhEzIfc?t=7m6s>https://youtu.be/eCBxNhEzIfc?t=7m6s 
(tape interfaced with a PC running Ansgar HPDIR)
<https://youtu.be/5J8IbpJoeqk>https://youtu.be/5J8IbpJoeqk (shows 
how I sniffed the HP-IB bus to figure out how the commands worked - 
or didn't, also has a demo of sending a rewind command in the raw 
via a paddled-in program)
<https://youtu.be/YS9dGYUbNd0>https://youtu.be/YS9dGYUbNd0 (showing 
a demo with the tape attached to an HP-85, using an FPGA based gizmo 
to take care of the on-the-fly parity generation)
<https://youtu.be/rAsLwcq4RNU>https://youtu.be/rAsLwcq4RNU (fixing a 
loading fault on the tape drive)


Although I love the HP 7970E dearly and want to encourage you to try 
your luck at it, that was a lot of work to get it to work on 
something it wasn't meant for. You'd have a much easier time 
bringing up a SCSI based tape.


Marc


Subject: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

Question:  Anyone have experience talking to a 7970 tape drive from
something other than an HP computer - something that does not have
HP-IB???  How is that usually done??

Jack Harper
Evergreen, Colorado




--
Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA

303.670.8375
303.670.3750 (fax)

http://www.secureoutcomes.net for Product Info. 

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jack Harper via cctalk]

Chuck -

Great information!

E.g., connectors from Anchor Electronics/San Diego - I have been 
wondering about primordial connectors.


I appreciate the description of your STM32F407 machine - makes sense 
and gives me hope that I can replicate the functionality in the 68K world.


I do have a dual trace 'scope and usually manage to use it without 
hurting myself too badly with a screwdriver or something :)


I have not looked yet - just printed the HP documentation - but are 
the lines into/out of the 7970 tape drive +5VDC etc or something 
weird that I will have to convert.  I "assume" that the current draws 
are reasonable for a GPIO approach?



Regards to the List,

Jack







If you get a 7970B or -C, get the service+operation manual from the HP
Museum.  Al has a bunch of 7970 stuff on bitsavers, but not, I think (I
could be wrong) the manual specific to the B and C models.  All of the
HP manuals have lots of detail (the drives had almost endless revisions
and additions, which can be confusing if you're just trying to figure
out what you've got)--and still, your drive may be slightly different.

For example, I've got a -B made in 1984 and the write-protect mechanism
doesn't match any of the variations in the manual.  This was important
to me as on of the microswitches was broken on mine.

But now that I've got the -B outfitted with 7/9 track read stack, write
protect doesn't matter so much.  I"m still tweaking the various
adjustments on the drive (have a dual-trace 'scope handy) and it's
getting very good.

Currently, I'm using it to read old 7-track tapes and create SIMH .TAP
files on a (shared) SDCard.

I used a generic STM32F407 evaluation board, mounted it on a hunk of
prototype board and fit a 50 line ribbon connectors to it.  Hookup
between the MCU board and the connector was done with wire-wrap.  The
MCU board even has a battery-backed real-time clock on it, so my files
are all correctly date-stamped.   I got the 48-conductor edge connectors
for the other end of the cable from Anchor Electronics in San Jose.

For switching between the heads, I built a small board that bolts to the
head mounting plate and contains a 34-line ribbon connector for the head
leads and a 20 line edge connector for the read preamp--and 5 small DPDT
DIP relays to do the switching.   The relay coils occupy a couple of
lines in the cable connecting the drive to the MCU, so I can shift
between the heads under software control.

So far, so good.

--Chuck


--
Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA

303.670.8375
303.670.3750 (fax)

http://www.secureoutcomes.net for Product Info. 

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jack Harper via cctalk]

Hello to Everyone that replied to my post on the HP7970 Tape Drive.

I very much appreciate the advice and counsel.

Sorry for the delay responding, I had a medical procedure that 
knocked me back a bit - nothing serious, just mostly irritating  (the 
ENT Doc injected 25ml of a liquid steroid direct into my inner ear 
Cochlear through penetration of the eardrum - Yuck!) 



My goal is to understand the feasibility of connecting a 7970 to the 
68K system that I have assembled.


I do not yet have a 7970 and it is probably a bit of a wait to find one.

I begin to believe that such a project is feasible, especially 
considering that people have done that sort of thing before to other 
processors.


Best that I can tell, there are no device drivers whatsoever for the 
Motorola 68K - Please let me know if I am wrong.


I begin to believe that a possible path would be to use a VMEbus 
digital in/out board to connect possibly direct to the HP7970 
control/read/write lines and then build ASM software to control that.


Running on a 50Mhz 68060 processor gives me hope that I will be able 
to stay ahead of the drive. Polling loops running hard should help there.


The key, I think, to that will be finding really detailed timing etc 
specifications.



Jay, I will look for documentation on the HP 13181/13183 tape 
controller - that certainly makes sense and will give me something to 
stare at :)


I just found it at HP Computer Museum: It's a pretty thing: 
http://www.hpmuseum.net/images/7970MagTape1-13181-60040-42.jpg


Just downloaded and printed the 13181/13183 tape controller 
documentation. I am much stronger in software than hardware, but will 
see if I can make sense of it.  Mostly what I need are the control 
lines: commands, timing...



Regards to the List,

Jack

ps - If interested, see https://www.youtube.com/watch?v=GfT96j-7Zjc 
to see what we did with some 68000 boards running ASM/Lisp back in 
the day 1985. It was a fun project - I ran and hid in my hole when 
that thing was running around - not kidding :)











At 07:58 PM 10/3/2017, Jay West wrote:


Jack wrote...

I begin to understand - so, for example an HP2100 with the 7970 tape option
had a specific tape controller board that talked direct to the 7970.

Yep, and no small amount of logic. The 7970A or B interfaced to a 2100/21MX
host using a 13181 interface (which is a two board set). The 7970E
interfaced to a 2100/21mx host using a 13183 interface (which is also a two
board set). Wasn't there some deal where a M/E/F could drive it at 45ips but
a 2100 couldn't (next lower speed)?? I don't recall for sure, but there was
something vaguely like that. And off that 13181/3 board you could have four
tape drives I believe.

-
I never used an HP2100 with a "real" tape drive such as the 7970 - actually
just paper tape back in 1974-1978 where I wrote in ASM (a bit ugly with no
index register) and ALGOL (I still have the box of paper tapes somewhere
with that four pass ALGOL compiler  - that nice black oiled paper with the
smell  :)

No... you did use a HP2100 with a REAL tape drive... such as the 2748B
*grin*Paper tape rocks. I have that same ALGOL compiler I'm sure secreted
away in a paper tape box(es).

--
I am delighted to hear that people have actually built a 7970 interface and
got it to work mostly in pure software.
That is good news and gives me hope :)
Interesting indeed.
Jay, I appreciate the helpful response.  Thank you.
--
Glad to help, but I just copied Chucks post from a few weeks back. He
supplied the knowledge :)

--
I will read the 7970 interface specifications more carefully now that I
understand better the context.  The timing issues are, of course, key.
--
HP manuals of the period are awfully detailed. They all have the theory of
operation section with a circuit walkthrough, etc. It could be helpful for
you to also take a look at the manual for the 13181 or 13183 controller set,
as you'll kinda be doing what that boardset does.

Best,

J


--
Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA

303.670.8375
303.670.3750 (fax)

http://www.secureoutcomes.net for Product Info. 

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[David Collins via cctalk]

Jay, if you have any scanned HP manuals that you don’t think are on line, I’d 
be happy to post them up on the HP Computer Museum site, giving credit where 
it’s due of course!

David Collins


> On 5 Oct 2017, at 8:10 am, Chuck Guzis via cctalk  
> wrote:
> 
>> On 10/04/2017 12:17 PM, Jay West via cctalk wrote:
>>> On 10/3/17 7:24 PM, Chuck Guzis via cctalk wrote:
>>> Al has a bunch of 7970 stuff on bitsavers, but not, I think (I could 
>>> be wrong) the manual specific to the B and C models.
>> 
>> I do have a chunk of HP service manuals (pretty sure 7970 included) that are 
>> in electronic format but have never made it online. If it needed, let me 
>> know what you're looking for.
> 
> Much appreciate, Jay.  I think I have what I need for time being.
> 
> --Chuck
> 

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Chuck Guzis via cctalk]

On 10/04/2017 12:17 PM, Jay West via cctalk wrote:
> On 10/3/17 7:24 PM, Chuck Guzis via cctalk wrote:
>> Al has a bunch of 7970 stuff on bitsavers, but not, I think (I could 
>> be wrong) the manual specific to the B and C models.
> 
> I do have a chunk of HP service manuals (pretty sure 7970 included) that are 
> in electronic format but have never made it online. If it needed, let me know 
> what you're looking for.

Much appreciate, Jay.  I think I have what I need for time being.

--Chuck

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[David Collins via cctalk]

Al, while I can’t rescan the thousands of documents already in the HP Computer 
Museum’s website and leave off the Australia stamp, I can assure you any future 
documents will be scanned as originally printed. 

I am in the process of sifting through many pallets of old duplicate HP manuals 
that were in storage as part of a cleanup and will put any items that were 
missed up on the site over time. 

You are of course welcome to include any of those on your site so there are 
multiple sources for these rare documents in the future.

David Collins
Curator
HP Computer Museum
Australia


> On 5 Oct 2017, at 4:06 am, Al Kossow via cctalk  wrote:
> 
> 
> 
>> On 10/3/17 7:24 PM, Chuck Guzis via cctalk wrote:
>> Al has a bunch of 7970 stuff on bitsavers, but not, I think (I
>> could be wrong) the manual specific to the B and C models.
> 
> I still have several tubs of HP manuals that I haven't gone through and
> I remember there were several revisions for the drive. At the time, I
> scanned the later versions.
> 
> Unfortunately, the Australians defaced every scan they made, so I will
> never include anything from them on bitsavers.
> 
> 
> 

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jay West via cctalk]

On 10/3/17 7:24 PM, Chuck Guzis via cctalk wrote:
> Al has a bunch of 7970 stuff on bitsavers, but not, I think (I could 
> be wrong) the manual specific to the B and C models.

I do have a chunk of HP service manuals (pretty sure 7970 included) that are in 
electronic format but have never made it online. If it needed, let me know what 
you're looking for.

J

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jay West via cctalk]

Re: 7970's with HP-IB support

I had written….

I've never once seen that option in the wild though


To which Ed# replied...

YES! hp 30  series  3000  systems and 40  series  had   hpib  1600 bpi
7970e  in early days.


Generally, there are far more 2100/21MX systems still around and kicking
than there are 3000 systems, so I'd say my original statement is correct.

J

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Al Kossow via cctalk]

On 10/3/17 7:24 PM, Chuck Guzis via cctalk wrote:
> Al has a bunch of 7970 stuff on bitsavers, but not, I think (I
> could be wrong) the manual specific to the B and C models.

I still have several tubs of HP manuals that I haven't gone through and
I remember there were several revisions for the drive. At the time, I
scanned the later versions.

Unfortunately, the Australians defaced every scan they made, so I will
never include anything from them on bitsavers.

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Curious Marc via cctalk]

 

Jack,

 

You can drive an HP-IB equipped HP7970E with an old PC that has an HP-IB card 
using Ansgar Kueckes HPDIR. I debugged it together with Ansgar. The rub is that 
it only worked well with an ISA HP-IB card running under Win98. The PCI HP-IB 
card running under XP uses a driver that causes timing errors and it skipped 
some records, and I don't think Ansgar ever bothered to fix it - we were happy 
enough to have made one solution work... The commands used to read and write 
from the tape are complex and tricky, and you have to get your timing right as 
there is hardly a buffer in the interface (128 bytes). And there is this weird 
parity thing, where parity has to be generated for commands on the HPIB bus, 
but not for data, or something of that ilk. If not the tape just hangs the bus. 
There are several GPIB emulators based on Arduino that should enable you to 
build an interface.

 

You know me, I made several videos documenting the work on the 7970E tape:

https://youtu.be/eCBxNhEzIfc?t=7m6s (tape interfaced with a PC running Ansgar 
HPDIR)

https://youtu.be/5J8IbpJoeqk (shows how I sniffed the HP-IB bus to figure out 
how the commands worked - or didn't, also has a demo of sending a rewind 
command in the raw via a paddled-in program)

https://youtu.be/YS9dGYUbNd0 (showing a demo with the tape attached to an 
HP-85, using an FPGA based gizmo to take care of the on-the-fly parity 
generation)

https://youtu.be/rAsLwcq4RNU (fixing a loading fault on the tape drive)

 

Although I love the HP 7970E dearly and want to encourage you to try your luck 
at it, that was a lot of work to get it to work on something it wasn't meant 
for. You'd have a much easier time bringing up a SCSI based tape.

 

Marc

 

 


Subject: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

 

Question:  Anyone have experience talking to a 7970 tape drive from 

something other than an HP computer - something that does not have 

HP-IB???  How is that usually done??

 

Jack Harper

Evergreen, Colorado

 

 

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Ed via cctalk]

YES! hp 30  series  3000  systems and 40   series  had   hpib  1600 bpi 
7970e  in early  days.  later they had   other  drives that  would   go  6250...
 
 
and I  wish I had  one  to  load  the   old   bulleting board email  chat  
software up on the   hp 3000 37 I have  here.
 
later  dried  were hpib also   but  theolder   30 and 40 series all 
used   7970e  hpib... I know I was there... I  owned some!
 
Ed Sharpe retired   ceo   computer exchange  Inc. 
now  seeing my life before me in museums 
 
 
 
In a message dated 10/3/2017 5:30:36 P.M. US Mountain Standard Time,  
cctalk@classiccmp.org writes:

I've  never once seen that option in the wild though, so I don't think one 
would say  "most" had it. I do have a handful of 7970E's running and a 7970B 
I should  probably get rid of Chuck Guzis had recently posted the 
following which  may shed light:

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Chuck Guzis via cctalk]

On 10/03/2017 06:58 PM, Jay West via cctalk wrote:

> HP manuals of the period are awfully detailed. They all have the theory of
> operation section with a circuit walkthrough, etc. It could be helpful for
> you to also take a look at the manual for the 13181 or 13183 controller set,
> as you'll kinda be doing what that boardset does.

If you get a 7970B or -C, get the service+operation manual from the HP
Museum.  Al has a bunch of 7970 stuff on bitsavers, but not, I think (I
could be wrong) the manual specific to the B and C models.  All of the
HP manuals have lots of detail (the drives had almost endless revisions
and additions, which can be confusing if you're just trying to figure
out what you've got)--and still, your drive may be slightly different.

For example, I've got a -B made in 1984 and the write-protect mechanism
doesn't match any of the variations in the manual.  This was important
to me as on of the microswitches was broken on mine.

But now that I've got the -B outfitted with 7/9 track read stack, write
protect doesn't matter so much.  I"m still tweaking the various
adjustments on the drive (have a dual-trace 'scope handy) and it's
getting very good.

Currently, I'm using it to read old 7-track tapes and create SIMH .TAP
files on a (shared) SDCard.

I used a generic STM32F407 evaluation board, mounted it on a hunk of
prototype board and fit a 50 line ribbon connectors to it.  Hookup
between the MCU board and the connector was done with wire-wrap.  The
MCU board even has a battery-backed real-time clock on it, so my files
are all correctly date-stamped.   I got the 48-conductor edge connectors
for the other end of the cable from Anchor Electronics in San Jose.

For switching between the heads, I built a small board that bolts to the
head mounting plate and contains a 34-line ribbon connector for the head
leads and a 20 line edge connector for the read preamp--and 5 small DPDT
DIP relays to do the switching.   The relay coils occupy a couple of
lines in the cable connecting the drive to the MCU, so I can shift
between the heads under software control.

So far, so good.

--Chuck

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jack Harper via cctalk]

Hello Jay et. al...

I appreciate the feedback.

I begin to understand - so, for example an HP2100 with the 7970 tape 
option had a specific tape controller board that talked direct to the 7970.


That certainly makes sense.

I never used an HP2100 with a "real" tape drive such as the 7970 - 
actually just paper tape back in 1974-1978 where I wrote in ASM (a 
bit ugly with no index register) and ALGOL (I still have the box of 
paper tapes somewhere with that four pass ALGOL compiler  - that nice 
black oiled paper with the smell  :)


I am delighted to hear that people have actually built a 7970 
interface and got it to work mostly in pure software.


That is good news and gives me hope :)

It sounds fairly straightforward with GPIO and a simple processor and 
probably a good sized chunk of fiddling around with timing and all 
that - e.g., gap detection.


The clocked data would certainly be a help.

The obvious(?) thing to do would be to wire-wrap a custom VME board 
similar to what Chuck Guzis did to interface into the 68K system that 
I have put together - but, I am far stronger in software than 
hardware (for sure) and the VME interface would be a headache for me 
- probably the main headache.


But, I could cure that by simply using a small processor of some sort 
on the wire-wrapped VME board and just draw power for that from the 
VMEbus - and transmit the data back and forth to the MVME177/68060 
processor board (actually five of those in my rack) across something 
simple such as serial or some such, though would certainly be better 
to go through the VMEbus.


Interesting indeed.

Jay, I appreciate the helpful response.  Thank you.

I will read the 7970 interface specifications more carefully now that 
I understand better the context.  The timing issues are, of course, key.



Regards and my best to the list.

Jack





At 06:30 PM 10/3/2017, Jay West via cctalk wrote:

Jack wrote
> Question:  I understand that most (all?) of the '7970 drives 
interfaced through the HP-IB IEEE-488 bus.


To which AEK replied
--
wrong.

full stop.
--

Welcome to our nook of the net. The grizzled veterans are here, and 
there's quite a few HP 2100/21MX folks lurking about. Ask away


To start... Al is correct. The 7970A/B used a basically proprietary 
interface. So did the 7970E, but on the E you could get an HP-IB 
option. I've never once seen that option in the wild though, so I 
don't think one would say "most" had it. I do have a handful of 
7970E's running and a 7970B I should probably get rid of Chuck 
Guzis had recently posted the following which may shed light:


- Chuck Wisdom Follows --
If you're accustomed to a Pertec interface, then the 800 interface 
isn't terribly different, just dumber.  You still have a connector 
for the basic motion and status commands (i.e. forward, reverse, 
rewind, high-speed and online, loadpoint, ready, protect) and you 
have two 8-bit+parity clocked data channels for read and write 
respectively, each with their own connector.


However, there is no formatter, as on Pertec interface drives.  You 
get the raw, framed and deskewed data on read and pretty much 
anything you want to put in on write.   No "handshaking" as the 
interfaces are not buffered. {snip} The lack of a formatter means 
that you'll have to do the work of gap detection, parity 
checking/generation and CRC/LRCC interpretation and generation 
yourself, as well as manage the control lines.


I used a small STM32F407 MCU board (about $10) which has lots of 5V 
tolerant I/O, so receiving data and status is no problem.  For 
driving control lines, simply set the GPIO pins for open-drain operation.
There's something like 24ma of sinking capacity on those, so again, 
no need for intermediate logic.   Since I'm interested in reading 
tapes, but not writing them, I can't address the issue of what to do 
about that end.  My setup uses a serial port for interaction and a 
USB port that makes the onboard SDHC look like a generic storage 
device.  So, read a tape, dump the data into the SDHC (Chan's FATFS 
software is useful); suck it out via the USB port to a PeeSee.


To handle 1600 PE data would require yet another layer of software.
--

Hope this helps

J


--
Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA

303.670.8375
303.670.3750 (fax)

http://www.secureoutcomes.net for Product Info. 

RE: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jay West via cctalk]

Jack wrote
> Question:  I understand that most (all?) of the '7970 drives interfaced 
> through the HP-IB IEEE-488 bus.

To which AEK replied
--
wrong.

full stop.
--

Welcome to our nook of the net. The grizzled veterans are here, and there's 
quite a few HP 2100/21MX folks lurking about. Ask away

To start... Al is correct. The 7970A/B used a basically proprietary interface. 
So did the 7970E, but on the E you could get an HP-IB option. I've never once 
seen that option in the wild though, so I don't think one would say "most" had 
it. I do have a handful of 7970E's running and a 7970B I should probably get 
rid of Chuck Guzis had recently posted the following which may shed light:

- Chuck Wisdom Follows --
If you're accustomed to a Pertec interface, then the 800 interface isn't 
terribly different, just dumber.  You still have a connector for the basic 
motion and status commands (i.e. forward, reverse, rewind, high-speed and 
online, loadpoint, ready, protect) and you have two 8-bit+parity clocked data 
channels for read and write respectively, each with their own connector.

However, there is no formatter, as on Pertec interface drives.  You get the 
raw, framed and deskewed data on read and pretty much anything you want to put 
in on write.   No "handshaking" as the interfaces are not buffered. {snip} The 
lack of a formatter means that you'll have to do the work of gap detection, 
parity checking/generation and CRC/LRCC interpretation and generation yourself, 
as well as manage the control lines.

I used a small STM32F407 MCU board (about $10) which has lots of 5V tolerant 
I/O, so receiving data and status is no problem.  For driving control lines, 
simply set the GPIO pins for open-drain operation.
There's something like 24ma of sinking capacity on those, so again, no need for 
intermediate logic.   Since I'm interested in reading tapes, but not writing 
them, I can't address the issue of what to do about that end.  My setup uses a 
serial port for interaction and a USB port that makes the onboard SDHC look 
like a generic storage device.  So, read a tape, dump the data into the SDHC 
(Chan's FATFS software is useful); suck it out via the USB port to a PeeSee.

To handle 1600 PE data would require yet another layer of software.
--

Hope this helps

J

Re: (Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Al Kossow via cctalk]

On 10/3/17 4:50 PM, Jack Harper via cctalk wrote:

> Question:  I understand that most (all?) of the '7970 drives interfaced 
> through the HP-IB IEEE-488 bus.

wrong.

full stop.

(Classic Computers) HP 7970 1/2" 9-Track Reel-to-Reel Tape Drive

[Jack Harper via cctalk]

Hello List -

I just joined the list a few days ago. I am delighted to have found you.

I have a couple of questions about the gorgeous HP 7970 Tape Drive - 
e.g., http://hpmuseum.net/images/7970A-43.jpg



Question:  I understand that most (all?) of the '7970 drives 
interfaced through the HP-IB IEEE-488 bus.  Do most (all?) of the 
tape drives include an HP-IB interface card?? Reason that I ask is 
that reading the 7970 specifications documentation makes me wonder as 
it really talks only about signal lines that do specific tapey things 
such as REWIND and the like and not anything that I saw specifically 
about HP-IB?   So, if I find a 7970 somewhere can I reasonably assume 
that the HP-IB interface card will be there?


Question:  I contemplate talking to the 7970 from the Motorola 68060 
development system that I have assembled through a VME <-> HP-IB 
interface VME board. There appears to be good documentation for such 
a VME <-> HP-IB board and I wonder if it makes sense to try to build 
a simple device driver for the 7970 tape drive in 68K assembly???   I 
do have a listing, for example, of an 7970 device driver written in 
HP2100 assembly language and could use that as a rough template, 
especially if I kept things as simple possible with polling, minimal 
if no interrupts, no DMA etc.  I wrote a lot of HP2100 assembly 
language software back ion the day and can understand that without 
too much difficulty - and I also built device drivers in 68K assembly 
years and years ago in another life.  Does any of that make 
sense??  Has anyone tried that sort of thing?


Question:  Has anyone tried to control a 7970 tape drive by using 
pure digital output - there are VME boards that make that easy to do 
that have, say, 32 input/output digital lines that are easy to 
read/write from within the 68K world.   Is that a feasible thing to 
think about or just madness?  At first blush, I can see how a 50Mhz 
68060 processor should be able to keep up with an early 1970's tape 
drive - or, maybe not...


Question:  Anyone have experience talking to a 7970 tape drive from 
something other than an HP computer - something that does not have 
HP-IB???  How is that usually done??


I greatly appreciate any advice and/or counsel.


Regards to the List,

Jack Harper
Evergreen, Colorado



--
Jack Harper, President
Secure Outcomes Inc
2942 Evergreen Parkway, Suite 300
Evergreen, Colorado 80439 USA

303.670.8375
303.670.3750 (fax)

http://www.secureoutcomes.net for Product Info.