My grandfather wrote a book, "This is the Way to Study"
SQ3R was the system
Study, Question, Read, Write, Review
Look over the chapter, read the captions of the pics, look at the bold text
then make notes of questions for things that pop up
Then Read the chapter through
Write down more questions
read again to find your answers
then do the problems at the end of the chapter
look over everything again, and see if u understand it all
have someone else quiz u, if needed
then review it all, and u should have a good grasp on it
My college friend says Wow, that is a LOT of work!
Is there an expectation now that being educated is NOT a lot of work?
--
Cindy Croxton
Electronics Plus
1613 Water Street
Kerrville, TX 78028
830-370-3239 direct
If anyone has spare time, and is familiar with discrete mathematics, I
have a friend who is a young college kid and desperately needs a tutor.
His prof just says to read the book, and take online quizzes. He is
failing. If you can help, please email me. He is in Delaware.
--
Cindy Croxton
Electronics Plus
1613 Water Street
Kerrville, TX 78028
830-370-3239 direct
>>> I suspect much of the electronics is fine. It would be good for someone
>>> wanting backup cards.
>> You must be joking. Those cards are done. Any chip that is still
>> operational will likely fail upon or shortly after power is applied.
> Most components can stand soldering temperatures. It is clear
> that it was only hot enough to melt plastics. That isn't even hot
> enough to damage boards.
I have physically seen the equipment in question, in the warehouse. A few
of the cards in the cage may still be salvageable - maybe, with some very
powerful juju. But much of the hardware is damaged *far* beyond any hope of
recovery. As Jim says, the
~~
Mark Moulding
Hi, I'm trying to ID this:
http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/QBUSMystMem.jpg
mystery QBUS memory card. I think it's a 64KB card, so not very important, but
it's bugging me. The company logo (lower left corner) looks familiar, but I'm
not good with off-brand logos; I'm hoping someone will recognize it. (It we
can locate a manual for it, so much the better; I'm not up to playing with it
to work out what the switches do!)
Noel
I received permission to share this link. These are in a personal
collection in Finland. Don't drool too hard :-)
https://imgur.com/gallery/7TKl5YH
--
Cindy Croxton
Electronics Plus
1613 Water Street
Kerrville, TX 78028
830-370-3239 direct
Hi folks,
I am looking for the following software products for a PDP-11, ideally to
be run on RSX-11M.
RJE/HASP
2780/3780 Protocol Emulator
My aim is to be able to submit a remote job from a simulated PDP-11 on simh
to a simulated IBM/370 on Hercules. The products that I mentioned seem the
obvious way to do this, but anything that works would be helpful.
Cheers
Peter Allan
I've not worked on 8" floppy drives, but have on tons of 5.25" single-
sided drives. Older single-sided ones (usually 35-track from the 70's)
had load solenoids for the pressure pads, as with a double-sided unit.
The pad is to provide good contact between the media surface and the
head beneath. I think older media must have ablated more than latter-
day media does, as it is rare to find a single-sided 5.25" drive with a
load solenoid. The pad is always in contact whenever the drive door is
closed. Double-sided drives of course retained the head-load solenoid
for some years, but eventually those were done away with. So, I think
that unless you are using a drive 24/7, a pad in contact with the disk
should not be a serious concern. That the pad IS properly in contact
is important of course, and pads should be inspected to see that there
is enough 'meat' left on them to provide the pressure needed. Aft of
the pad, at the base of the head-sled pressure arm is a notch into
which the end of the spring rides. Close examination of the sled will
probably show some higher and lower notches into which you can move the
end of the spring, to provide more or less pressure as needed, to tune
a particular drive.
In the old days, someone running a drive on a BBS or other heavy
application might wear a pad out. We'd just steal one from a cassette
tape and stick it on the arm. The cassette tape pad was square and the
originals were round, but it never seemed to make any difference.
These days there are no cassettes floating around to cannibalize, so I
buy felt pads for furniture from Amazon, trim them with a razor and
stick them on a drive I'm refurbishing. Atari, Commodore, Tandy...
Many of the 80's 8-bits used this very scheme on their single-sided
drives and this solution is good for all of them.
I had someone insist to me recently that the felt pads I was buying
were acrylic and the originals were Rabbit Hair and that it was crucial
that the replacements be made of rabbit hair. In practice, and that is
40 years of practice, any old pad will do just fine. If it looks like
the right thing it will serve the purpose. Just pick off the old nub
of a pad and stick on your newly cut one and go.
Common faults I've been noticing are that disk drives made in the 70's,
80's, and 90's are failing in common ways. I attribute these failures
mostly to lack of lubrication. After 30 years they get a bit gummy and
the actuators have to work harder to move the head sled, which puts a
greater load on the darlington drivers which power the actuators, which
causes the drivers to fail. Replacing the drivers will often restore
the drive to working order, but they will fail again in short order if
the original probelm is not resolved. I simply clean the rails and
stepper bands, touch a little wd40 to the rails to free the head sled,
cycle the head back and forth a buncha times manually to exercise it
and distribute the lubricant, then follow that will a little white
lithium grease for a longer-lived lube. Not only will the drive run
better and a lot quieter when lubricated, the loads on the actuators
and their associated electronics are greatly reduced, making for a
like-new drive.
The second thing that is happening quite often is electrolytic
capacitors are failing, leaking or not. I had a pair of drives the
other day which made quite a racket when spinning free even without
media installed. Replacing the electrolytics on the spindle motor's
board got rid of the noise and made it possible to properly tune the
RPM's, which had been just all over the map.
best,
Jeff
> Date: Fri, 9 Oct 2020 02:29:46 -0400
> From: Bob Vines <bobvines00 at gmail.com>
> To: cctech <cctech at classiccmp.org>
> Subject: Tips on reviving a TU56 + TD8E?
> I don't have a TU56 & TD8E _yet_, but really hope to get one fairly soon --
> if successful, they will most assuredly require troubleshooting & repairs.
> Where did you find the source for TDFRMT? Also, where did you find the
> MAINDEC document that matches your version of the TD8E MAINDEC? I ask
> because I've had _great_ difficulty finding MAINDEC docs that actually
> match whatever MAINDEC images I've tried to use.
Bob,
The source for TDFRMT, as well as the rest of OS/8 can be found here:
https://tangentsoft.com/pidp8i/file?name=src/os8/ock/CUSPS/TDFRMT.PAhttps://tangentsoft.com/pidp8i/dir?ci=tip&name=src/os8
Several versions of the TD8E MAINDEC can be found here:
http://so-much-stuff.com/pdp8/software/maindec.php
Only one of them has a PDF, and I haven't checked to see if they fully
match up with the binaries, but the starting addresses of the tests I'd
been checking at least seem to match up with the DHTDAB.DG binary found
here: www.pdp8.net/pdp8cgi/os8_html?act=dir;fn=images/os8/diagpack2.rk05
Regards,
-Tom
mosst at sdf.org
SDF Public Access UNIX System - https://sdf.org
>
> Message: 8
> Date: Wed, 7 Oct 2020 05:59:40 +0000 (UTC)
> From: Thomas Moss <mosst at SDF.ORG>
> To: cctalk at classiccmp.org
> Subject: Tips on reviving a TU56 + TD8E?
>
...
> I've recently bought a TU56 for my PDP-8/e, and am looking for some
> advice on getting it to work.
>
...
> ... I found a copy of the source for TDFRMT so I could see what
> exactly was causing the "SETUP?" error.
>
...
Tom,
I don't have a TU56 & TD8E _yet_, but really hope to get one fairly soon --
if successful, they will most assuredly require troubleshooting & repairs.
Where did you find the source for TDFRMT? Also, where did you find the
MAINDEC document that matches your version of the TD8E MAINDEC? I ask
because I've had _great_ difficulty finding MAINDEC docs that actually
match whatever MAINDEC images I've tried to use.
Thanks,
Bob
> From: Ethan Dicks
> a DEC sync serial board since that part is nowhere to be found right
> now.
I dunno, I see them fairly often on eBait (well, often compared to some other
things, e.g. TU56 parts... :-)
QBUS or UNIBUS? And there are lots of different ones, which I confess I don't
fully understand the difference between (e.g. DP11, DQ11, DU11, DUP11, DV11) -
some of it's single-line/multi-line, and DMA/programmed I/O, but from what few
details I looked at - while doing:
http://gunkies.org/wiki/DP11-A_synchronous_serial_line_interfacehttp://gunkies.org/wiki/DUP11_synchronous_serial_line_interface
there are also differences in exactly which protocools are supported,
etc, etc, etc, etc.
Noel
