GPIB + disk drives

From: Joe <rigdonj_at_intellistar.net>
Date: Mon Mar 23 12:18:54 1998

At 12:25 AM 3/23/98 +0000, you wrote:
>>
>> I could use a quick tutorial on GPIB as it applies to computer device
>> interfacing.
>
>GPIB ~ IEEE-488 ~ HPIB...
>
>The original IEEE-488 standard only specified the _hardware_ of the
>interface - signals, timing, etc. It meant that two devices could be
>plugged together without the magic smoke leaking out, data could flow,
>but they needn't understand each other.
>
>Certainly later HPIB standards specified things like the ASCII character
>set would be used for text, and that numbers would be sent as normally
>read - most significant digit first if sent in ascii.
>
>The command sets for particular devices AFAIK were never specified. HP
>had a whole lot of them for their own peripherals, but other
>manufacturers were free to do what they wanted.
>
>[Reading GRID drive]
>> The card and low-level drivers seem to work great, but I can't find any
>> higher-level drivers that know how to talk to this drive (or any drive,
>> for that matter). Do drives that talk GPIB all talk the same way?

   No, HP uses at least three different "standard" command sets for drives
and countless non-standard ones. I have a LARGE book from HP that gives
file conversion programs for some instruments (not even
computers/calculators or anything else) and there are probably well over a
hundred formats described in it.


If so,
>
>Not at all, alas. HP drives probably use the CS/80 command set, or the
>cut-down Amigo command set. Commodore PET drives had their own commands
>which made extensive use of extended secondary addresses. Other
>manufacturers probably did their own thing.


  Tony's right, many manufacturers didn't implement the full set of HP-IB
commands/functions. If you look at many HP-IB devices, you find a codes
like SH 0, AH 1, DC 2, etc printed near the HP-IB port. The letters are
the abbreviation for different command or functions and the number gives
the capability level for that function. 0 always means no capability. But
full capability is 1 for some functions like Source Handshake (SH) or it
may be as high as 8 for others. You'll have to get the specification from
IEEE or HP or another manufacturer to understand the codes.

>
>> any idea where I might be able to find an MS-DOS driver that sits on top
>> of the GPIB driver I've installed?
>
>HP sold a driver to use some of the smaller HP disk and tape units with
>an MS-DOS machine. Probably absolutely no use for this problem, though.
>
>>
>> Should I give up on this approach and simply pull the drive out of the box
>> and see if I can talk to it with an MFM controller? It's a 10MB 5.25"
>> drive from around 1982, so I'm assuming it's a Seagate.

   It could be almost anything. I've seen Seagate 225s in some drive boxs
but large Quantum drives in other box with the same model number!

>
>Alas MFM controllers are equally non-standard at the format level. So
>it's not at all certain that a PC controller could make sense of the data
>on this drive.

   MFM would definitely *NOT* make sense of the data! The formats are
completely different! There is no FAT table on HP drives and when you
format them, you tell the system how many files to allocate on the drive
and it creates that many directory entries, so the number of dir entries
isn't even constant! PLUS many of the drives are partioned by hardware
control.

   You might be able to use the drive but you'll have to LL format it and
start from scratch.

  Joe

>
>>
>> -- Doug
>>
>>
>>
>
>-tony
>
>
Received on Mon Mar 23 1998 - 12:18:54 GMT