Do you have any interest in adding an HP 9000 Series 400t Workstation (HP/UX), complete with VRX Graphics and 19" 98754A monitor, to your collection?
Regards,
Paul Bartlett.
London
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I use a Cipher M995S 9 track on a 486PC w/ DOS and Adaptec
controller ...using either Central Point Backup v.9, or John Wilson's
(dBit) Scsi Tape utility.
~ J
> I have the same question. The ST506 and ST412 were different
> in the WrPrecomp signal being changed to a head select for
> the ST412. I think he is looking at documents that state that he
> needs a ST506/412 interface. This would be compatable with
> just about any MFM drive made after the ST412.
>
> There was a signal on some drives that came on the data cable.
> I think it may have been a write protect but I don't recall
> exactly what it was. The ST506 may have used this signal.
> I'm not sure if this is what he is talking about.
Some, if not most, ST506/ST412 interface drives output a signal on the
data cable when that drive is selected. The idea was you could plug the
data cables into the controller in any order, and the controller could
determine which data connector to use, which receivers to enable, etc.
It's a pity few controllers made use of that!
I'm not aware of any write-protect signal on the data connector of any
such drive.
-tony
I'm not sure how the name was spelled, so I put both here.
basically it was a vax in a notebook type arrangement.
I once located one in London ontario, but I've lost contact with the person who had it :(
so if anyone has one, I've been looking for a very long time, and it'd be appreciated.
thanks!
Dan.
_________________________________________________________________
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http://asksantaclaus.spaces.live.com/
>From a digest article I must comment on...
> Is it possible to connect two modems (eg: Hayes 2400 to Hayes 2400)
> using a 'dead' or isolated pair of copper wire and have them be able
> to communicate?
As said before, just get one modem in Originate mode, and the other in Answer
mode and go from there. Most "modern" modems (that have some Part 68
certification) can do this quite easily as long as you have access to the
command stream on each side. The more difficult is when you don't (usually on
one side). Then you attempt to get the "answering" modem in answer mode
sending its carrier before he "originating" modem asks for it, and will sense
it when it wants to. The part that is touchy is making the timeout on the
"answer" side long enough.
Ob ClassicComp: I should really try this with my Bell 103A modem (I got one,
don't ask!) to see if I can get it to "connect". It might need some DC voltage
>from tip to ring (green wire to red wire) to trip some relay (it was before
optical couplers!). What an experiment to do!
If you want to make two "500" sets talk to each other, a nice 6 Volt battery
works quite well placed in series with the two sets. It won't make them ring,
but you CAN talk. Use a lantern battery (or 4 D cells) and unless you are
making DTMF (touch-tone) on a polarity sensitive set (older 2500 sets) polarity
makes little difference.
--
Sorry,
No signature at the moment.
____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs
> From: pete at dunnington.plus.com
<http://www.classiccmp.org/mailman/listinfo/cctalk>
---snip---
>>
>> There was a signal on some drives that came on the data cable.
>> I think it may have been a write protect but I don't recall
>> exactly what it was. The ST506 may have used this signal.
>> I'm not sure if this is what he is talking about.
>
> There's a "drive selected" signal, but I think most drives have that.
> It's there because the 34-way control cable is daisy-chained but the
> 20-way data cable is radial, one per drive.
Yes, that may have been it. If he is using just one drive,
this shouldn't be an issue.
>
>> I'd suspect things like step rate and number of heads would
>> be more important to him than anything else.
>
> The other important difference between the ST506 signals and the ST412
> was that the ST506 didn't support buffered seek; the timing of the step
> signals had to be slow enough that the stepper motor could keep up. The
> ST412 was the first drive that buffered the step signals, so they could
> be sent rapidly, and virtually every hard drive after that did too.
>
This is important because many drives that had the auto step, were
really slow using the fixed rate step. I had this problem getting
a ST251 to run on my Olivetti M20. The original drive had a fast step
rate of something like 6 ms. The ST251 wouldn't work faster than
10ms as I recall but the auto rate was much faster.
I think we need to hear from Andrew to see just what it is he
is talking about. From his original post, I still think he has something
confused.
Dwight
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________________________________
-----REPLY-----
Hi,
Yes, I'll admit this can be a bit confusing and I am bit puzzled by it as
well. I had not heard of anything like it either but I have to believe the
VG engineer to know what he is talking about.
However, I have heard from a former Vector Graphic engineer who is
intimately familiar with the VEDMCS (aka, the integrated FD/HD controller)
and he tells me that the ST506's used for the VEDMCS are different than the
generic "off the shelf" ST506 hard drives. I believe the stock ST506 is
modified or configured to provide the signal in some manner.
The different signal is called a "constant index" signal. Apparently, it is
similar to an /INDEX signal from a floppy drive interface but the signal
tells the HD controller everytime sector 0 passes around. The HD controller
requires it for setting up the PLL.
Here is an excerpt on the subject from the VG engineer:
"
All hard drives working with a Vector FD/HD must have constant
index. There is a phase locked loop that is controlled by U20 which
is CMOS 4040 chip and unless you have constant index the PLL never
has time to sync up and gives read errors.
"
I have seen the VEDMCS driver source code and it specifically lists the
ST506 and the ST412 as its only two supported drives. I'd like to start
witho one of those and see if I can get it work.
Maybe I could convince it to accept a ST225 instead of a ST412 but so far I
haven't had any luck. I keep getting "drive not ready" errors.
I hope this helps explain this situation.
Thanks!
Andrew Lynch
So on the 24th I trucked up to Milwaukee (from Chicago) for a $100 SGI
haul, the star of which was a working Crimson with three hard drives.
Brought back the Crimson and some Indigo 2s (which will be for
sale/trade/free as soon as I inventory them.) There was supposed to
be an O2 as well, but it went missing. So for the pre-arranged price
I asked to hunt around the shop for a replacement item, which turned
out to be the back-breaking HP 88780B 9-Track Tape Drive! A fair
trade-up, I'd say.
So I've got it home and onto a table. This may be old-hat to some,
but having never used a 9-track before I have to say the air-powered
self-threading mechanism is the coolest thing I've seen all month. I
loaded a blank tape for the self-test, which passes. Now to get it to
write some real data, and eventually use it to rescue some old tapes
I've had for years as well as the one I bought at VCF.
I'm guessing that any modern *nix machine should recognize it and be
able to read it. I planned on using a Sparc IPX or something
similarly portable when I get one formatted and loaded. In the
meantime, I have my laptop. Is there any chance of getting WinXP to
use this beast? I have a SCSI PCMCIA card on the laptop which I've
used to read old hard drives, but drivers will be the issue here. I
know in most cases the backup software needs to be able to handle the
drive as well as the OS - anyone tried to use Backup Exec or any of
the other big commercial s/w with one of these?
Thanks in advance...
--
jht
A greatly updated history of Alpha Micro, including their use of alternative
operating systems such as UNIMOS/Unix and Pick, and the invasion of the clone
systems, is now up on the Alpha Micro Phun Machine. In addition, the models
page is tremendously expanded with corrected chronology and more information
on loadouts. This is all with the help of Bob Fowler, who graciously
allowed me to raid his AMUS document archive and take images.
He also put a lot of his software onto a QIC tape for me, but naturally my
AM-626 streamer has decided to be recalcitrant, so this will wait for the
next update until I can fix it.
Also, I recently acquired an AM-1200, and there will be a model page for that
as soon as I get it operational.
http://ampm.floodgap.com/
--
------------------------------------ personal: http://www.cameronkaiser.com/ --
Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com
-- The son becomes the father, the father becomes the son, the uncle has a beer.
> Failing that, if you have bootable Linux CD, it should deal with the
> drive just fine.
Apparently, modern Linux distros have depreciated the 'mt' command. You have
to install the 'mt-st' package to get it. Eric Smith's tapecopy program seems
to work ok, other than the known quirks like an endless stream of -1 length
blocks if the tape stalls.
> > From: pete at dunnington.plus.com
> ---snip---
> >>
> >> There was a signal on some drives that came on the data cable.
> >> I think it may have been a write protect but I don't recall
> >> exactly what it was. The ST506 may have used this signal.
> >> I'm not sure if this is what he is talking about.
> >
> > There's a "drive selected" signal, but I think most drives have that.
> > It's there because the 34-way control cable is daisy-chained but the
> > 20-way data cable is radial, one per drive.
>
> Yes, that may have been it. If he is using just one drive,
> this shouldn't be an issue.
Actually it would be if the controller depends on it, even if you only
have one drive. If that drive doesn't output the 'drive_selected_ signal,
then the contorller might not enable any data receivers.
>
> >
> >> I'd suspect things like step rate and number of heads would
> >> be more important to him than anything else.
> >
> > The other important difference between the ST506 signals and the ST412
> > was that the ST506 didn't support buffered seek; the timing of the step
> > signals had to be slow enough that the stepper motor could keep up. The
> > ST412 was the first drive that buffered the step signals, so they could
> > be sent rapidly, and virtually every hard drive after that did too.
> >
> >
> This is important because many drives that had the auto step, were
> really slow using the fixed rate step. I had this problem getting
The really strange lone (not the same interface, of course, but similar
in concept) is the SA4000 (14" Winchester). On that drive, you eitehr
have to send pulses so slowly that the the head movement it completed
for each one (that is, the head gets to the next track before you send
the next pulse) or fast enough that you've sent all of them before the
heads start to move. An intermediate rate will end up with the darn thing
mis-stepping. This is docuemtned in the manaul and the reason for it
(one up/down counter with a common clock input to record the head offset)
is clear from the schematics.
-tony
