Jack wrote....
> Question: I understand that most (all?) of the '7970 drives interfaced
> through the HP-IB IEEE-488 bus.
To which AEK replied....
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wrong.
full stop.
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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.
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Hope this helps....
J
