28 Sep
2011
28 Sep
'11
8:22 a.m.
I did a fair amount of research and coding for TU58 emulation over the
years, most of that experience and links to utilities for MSDOS and Linux
are available at http://www.willsworks.net/pdp11/tu58-emu.htm
29 Sep
29 Sep
5:48 a.m.
how do you physically wire the drive to the PC ?
Date: Wed, 28 Sep 2011 11:22:20 -0400
To: cctalk at classiccmp.org
From: will_kranz at softhome.net
Subject: Copying in a real TU-58 one virtual TU-58 tape
I did a fair amount of research and coding for TU58 emulation over the
years, most of that experience and links to utilities for MSDOS and Linux
are available at http://www.willsworks.net/pdp11/tu58-emu.htm
11:30 a.m.
On Thursday (09/29/2011 at 08:48AM -0400), Dan Gahlinger wrote:
--
Chris Elmquist
how do you physically wire the drive to the PC ?
I am just using some jumper wires currently... three of them...
Hook TxD of the PC to RxD+ of the TU-58
RxD PC TxD+ TU-58
GND PC GND TU-58
I use jumpers from Sparkfun,
http://www.sparkfun.com/products/9389
F/F with a contact on each end that slides over a pin. I slide it over
the pin in the 10-pin header on the TU-58 and slide it over the pin on
the DB9M on the PC's serial port (well, at the end of a straight thru
F->M cable).
Note that the drive needs to be wired for RS423 mode and not RS422. The
tech ref manual here,
http://bitsavers.org/pdf/dec/dectape/EK-0TU58-TM-001_TU58tech.pdf
on PDF page 44.
I've got it talking now with a simple Linux app.
But it appears that my drive has some issues. I can command it to seek
to a particular block, the motor spins up, advances the tape a small
amount and then stops, at which point the drive returns an "END PACKET"
with an error status of "motor stopped".
The motor is free to turn... even with a tape installed and I've scoped
for usual things such as tach pulses coming back, etc. so the failure
is non-obvious at this point.
I did find that one of the tapes failed the first time the drive tried to
move it. Broke the little belt inside just as I suspected might happen.
Moved on to another tape and that one is holding together so far.
More to investigate.
Chris
Date: Wed, 28 Sep 2011 11:22:20 -0400
To: cctalk at classiccmp.org
From: will_kranz at softhome.net
Subject: Copying in a real TU-58 one virtual TU-58 tape
I did a fair amount of research and coding for TU58 emulation over the
years, most of that experience and links to utilities for MSDOS and Linux
are available at http://www.willsworks.net/pdp11/tu58-emu.htm
1:16 p.m.
On 09/29/2011 02:30 PM, Chris Elmquist wrote:
But it appears that my drive has some issues. I can
command it to seek
to a particular block, the motor spins up, advances the tape a small
amount and then stops, at which point the drive returns an "END PACKET"
with an error status of "motor stopped".
The motor is free to turn... even with a tape installed and I've scoped
for usual things such as tach pulses coming back, etc. so the failure
is non-obvious at this point.
I did find that one of the tapes failed the first time the drive tried to
move it. Broke the little belt inside just as I suspected might happen.
Moved on to another tape and that one is holding together so far.
More to investigate.
I believe there's an optical shaft encoder on the spindle motor of
the TU58. I'd check to see that the disk (which is paper-thin sheet
metal) and the opto interruptor aren't clogged up with dust bunnies,
then test the opto interruptor itself.
-Dave
--
Dave McGuire
Port Charlotte, FL
1:29 p.m.
On Thu, Sep 29, 2011 at 4:16 PM, Dave McGuire <mcguire at neurotica.com> wrote:
?I believe there's an optical shaft encoder on the
spindle motor of the
TU58. ?I'd check to see that the disk (which is paper-thin sheet metal) and
the opto interruptor aren't clogged up with dust bunnies, then test the opto
interruptor itself.
I can't remember the symptoms when it doesn't work, but it's a good
thing to check. If the device was powered on for thousands and
thousands of hours, the IR diode could be a bit dim - I've seen that
with 15+ year old optical interrupters before (and successfully
repaired the gear with a new interrupter).
-ethan
5:38 p.m.
On Thursday (09/29/2011 at 04:29PM -0400), Ethan Dicks wrote:
On Thu, Sep 29, 2011 at 4:16 PM, Dave McGuire
<mcguire at neurotica.com> wrote:
Ya... good idea except, I can measure nice clean tach pulses on the
board after the op-amp stage that the photo transistor in the interrupter
drives. So, I think I'm getting good tach signal from the interrupter.
I've completely cleaned the unit so the dust bunnies have been long since
exorcised.
--
Chris Elmquist
?I believe there's an optical shaft encoder
on the spindle motor of the
TU58. ?I'd check to see that the disk (which is paper-thin sheet metal) and
the opto interruptor aren't clogged up with dust bunnies, then test the opto
interruptor itself.
I can't remember the symptoms when it doesn't work, but it's a good
thing to check. If the device was powered on for thousands and
thousands of hours, the IR diode could be a bit dim - I've seen that
with 15+ year old optical interrupters before (and successfully
repaired the gear with a new interrupter). 
1:35 p.m.
I believe there's an optical shaft encoder on
the spindle motor of the
TU58. I'd check to see that the disk (which is paper-thin sheet metal)
and the opto interruptor aren't clogged up with dust bunnies, then test
the opto interruptor itself.
What is the difference from a TU58 to a normal DC-600 drive? Can't be
used a normal DC-600 (e.g.: for PC) in place of a TU-58?
I don't have anything DEC, just out of curiosity :)
2:01 p.m.
On 09/29/2011 04:35 PM, Alexandre Souza - Listas wrote:
It's a completely different form-factor of tape, for one thing. ;)
The TU58 is a DC100-style cartridge.
-Dave
--
Dave McGuire
Port Charlotte, FL
I believe
there's an optical shaft encoder on the spindle motor of the
TU58. I'd check to see that the disk (which is paper-thin sheet metal)
and the opto interruptor aren't clogged up with dust bunnies, then
test the opto interruptor itself.
What is the difference from a TU58 to a normal DC-600 drive? Can't be
used a normal DC-600 (e.g.: for PC) in place of a TU-58?
I don't have anything DEC, just out of curiosity :) 
2:17 p.m.
On 29 Sep 2011 at 17:35, Alexandre Souza - Listas wrote:
What is the difference from a TU58 to a normal
DC-600 drive? Can't
be used a normal DC-600 (e.g.: for PC) in place of a TU-58?
I don't have anything DEC, just out of curiosity :)
Other than physical aspects of the tape cartridge and drive, the TU58
uses a factory-preformatted tape with special marks recorded for BOT
and EOT. A DC600 QIC02 style tape uses holes punched into the tape
and an optical sensor to determine BOT/EOT.
The TU58 is actually closer to a 3M Iotamat drive.
Given the cantankerousness of the medium, however, TU58 emulators
have been developed.
--Chuck
30 Sep
30 Sep
4:09 a.m.
On 09/29/2011 04:16 PM, Dave McGuire wrote:
And the wires are not broken.
Allison
On 09/29/2011 02:30 PM, Chris Elmquist wrote:
> But it appears that my drive has some issues. I can command it to seek
> to a particular block, the motor spins up, advances the tape a small
> amount and then stops, at which point the drive returns an "END PACKET"
> with an error status of "motor stopped".
>
Look at the response packets for error information. Also what was the
command
as it may be an irrational command.
FYI: Dectape-II are nt generic tapes. they have DEC specific formatting
that must be there. Also make sure you have not gone off the end of the
tape.
usually the first program (on the 11)I run is one to re-tension the tapes.
ITs a seek to block 127 and back to block 0.
The motor is
free to turn... even with a tape installed and I've scoped
for usual things such as tach pulses coming back, etc. so the failure
is non-obvious at this point.
I did find that one of the tapes failed the first time the drive
tried to
move it. Broke the little belt inside just as I suspected might happen.
Moved on to another tape and that one is holding together so far.
More to investigate.
I believe there's an optical shaft encoder on the spindle motor of
the TU58. I'd check to see that the disk (which is paper-thin sheet
metal) and the opto interruptor aren't clogged up with dust bunnies,
then test the opto interruptor itself.
-Dave
4614
days inactive
4616
days old
9 comments
8 participants
participants (8)
-
ajp166＠verizon.net -
cclist＠sydex.com -
chrise＠pobox.com -
dgahling＠hotmail.com -
ethan.dicks＠gmail.com -
mcguire＠neurotica.com -
pu1bzz.listas＠gmail.com -
will_kranz＠softhome.net