HP 7980 HPIB Interface

[Daryl Warkentin]

I need documentation on the HPIB interface to an HP 7980A 9-track tape drive. I concerned only with the protocol for storing and retrieving files from the drive. The ultimate use of this information will be to interface the drive to a Linux PC.

[paul courry]

What is it *exactly* that you are looking for? What signals are on what pins? Storage formats? ???

[Daryl Warkentin]

I am looking for the software protocol used to access files on the tape. Like, what command would I send to tell the tape to rewind or to store some data. If this drive is similar to other HPIB devices there should be some ASCII based message system that is used to control the drive. I am assuming the hardware interface will be easy to set up as long as addresses are assigned to the drive and master HPIB card.

[David Ruska · Accepted solution]

The 7980 follows the IEEE 488 interface electrical standard. The software protocol is derived from the HP Amigo disk protocol. This is a bit more complicated then the ASCII command sequences sent to HP-IB instruments. These devices use primary addresses for physical addressing, and the secondary addresses (either talk or listen) are used as commands. To indicate completion of a tape command, the device implements parallel polling.

Here's the sequence to rewind the tape:

MLA X [My Listen Address

]
MSA 1 [My Secondary Address 1 = Tape Cmd]
DAB 13 [Data byte of 13 = Rewind ]
Tagged with EOI (end or identify)
UNL [Unlisten]

(wait for parallel poll)

MTA X [My Talk Address ]
MSA 16 [Read Device Specified Jump]
DAB W/EOI [Device returns 0 or 1]
UNT [Untalk ]

Hopefully this gives you an idea of what's involved. If you need all the protocol specifics let me know. Unfortunately this was developed before the days of pdf files, so I'd have to find a paper manual and scan it in :-)

[Daryl Warkentin]

Thanks David,
I would like to have the documentation. I have talked to at least ten different departments at hp to get my hands on it, so I am extremely grateful for your reply. I don't want to put you to work in the copy room though. Is there a document number that I could use to have a copy made, and shipped to me?

[David Ruska]

Daryl,

I suspect the documentation is out-of-print.

Send me your postal mail address to the following email address: ltt_team@hp.com, and I will make a hard copy for you.

[Orhan]

Dear David Ruska, We have the problem like Daryl Warkentin and quoted his message to remind you. We have a hp7974A tape unit and wishes to control it via hpib card. The following sentence is also my problem and the solution you provide hopefully answer my questions as well. Could you post the relevant documentation to the odemir@metu.edu.tr e-mail address, please?. I will be very glad..Thanks in advance.Looking forward to hearing you.
"I am looking for the software protocol used to access files on the tape. Like, what command would I send to tell the tape to rewind or to store some data. If this drive is similar to other HPIB devices there should be some ASCII based message system that is used to control the drive. I am assuming the hardware interface will be easy to set up as long as addresses are assigned to the drive and master HPIB card."

[David Ruska]

Orhan,

I do have a hard copy of the HP-IB interface specifications for the 7974/7978/7979/7980. The last revision was in 1989.

If you want, I can send you a reproduction. Another fellow had recently requested it this manual, and suggested that he might be able to provide a scanned (electronic) copy back to me.

For background, the tape drive does not use ASCII messages (like many GP-IB instruments do). Rather, it uses secondary talk and listen addresses to specify commands and request status information. The command sequences are one or two bytes, and the status messages returned are one to six bytes. It should not be hard to write a driver for this. I can provide some tips on turning on a driver if you wish. Just send your email address to ltt_team@hp.com (if you have not already).

[Mike00]

Hello,

I am also looking for a copy of this document. This seems to be an ancient thread. Has a pdf version of this document ever been made which I could get a hold of? Any help would be appreciated. Thanks