12 Jun
2016
12 Jun
'16
11:18 a.m.
On 6/12/2016 12:00 PM, Rod Smallwood wrote:
On 12/06/2016 16:19, Jerome H. Fine
wrote:
Thanks Jerome
Rod
Trim on long bottom posts, please.
Especially if there's nothing
interesting added at the bottom.
- J.
Rod
Smallwood wrote:
Firstly one important fact
that I did not know. If you bulk
erase a TK50 you can turn it into a
TK70 tape with an INIT.
Thank you I did not know that.
A bulk erase was the first thing that
seemed to be the solution
since I had, fortunately, found a
blank TK50 tape and was
able to use it to both read and write
in a TK70. There was
a long discussion, probably a decade
ago, about CompacTape,
supposedly just for the TK50, and
CompacTapeII, supposedly
just for the TK70. From a Memorex
internet site, probably over
10 years ago and long gone now, there
was a table of all of the
physical characteristics of
CompacTape. While the tapes for
even higher density drives were
different, the physical properties
of CompacTape (I) and CompacTapeII
were IDENTICAL!!!!
So that also gave me the confidence
to use the CompacTape
media in the TK70 drives - which gave
excellent results.
Let us know if you are finally
successful with the TK70 drives
and tapes.
Secondly I have made a little
discovery. We all know the tapes go
sticky and attach themselves to
guide rollers etc.
Well its not always the tape.
I have three instances of tapes that
would not feed or lace up where I
got rid of the problem
without doing anything to the
tape at all. In fact all subsequent
tapes have had no problems. It
took 30 seconds and
apart from taking the metal
cover off the back off the drive I
dismantled nothing.
If I am right and can run a
load of tapes through the drive.
Then I'll say what I did. If I'm
wrong then nobody will needlessly
try my method.
I will say its not cleaning
the heads or the EOT sensors. You
should do that any way.
It would be appreciated if you would
state what you did in any case.
It is always helpful to know what has
been tried and does not produce
a result since it can be ignored in
the future.
Its clear the way to go is
bulk erase TK50 tapes and then to
use the TK70 drive and controller.
Was there ever a UNIBUS TQK70
controller?
I never used Unibus, so I never found
out. YES!! Bulk
erase is easy and does work well.
RX02 and a RX01 (I have one of
each and a spare chassis)
I'll be back to them when this
tape situation is sorted.
I had got to the stage where I
could get commands through to the
drive electronics
I have an RX02 around which I have
not used in a while. My
preference, if I need the RX02
hardware is to use the DSD 880/30
which has an RX03 drive which can
also function as an RX02 and
also reads and writes RX01 media as
well. My RX03 drive has
been modified by placing a DPDT
switch into the detection circuit
for the single-sided vs double-sided
sensors. That way, I can use
any RX02 floppy media as double-sided
without having to punch
the extra holes. The DY.MAC device
driver from V04.00 of RT-11
contained extra code to support
double-sided operation, but that
code was no longer present with the
V05.00 of DY.MAC when
it was released in 1983. So I added
the code back and that
made the DYX.SYS device driver under
RT-11 able to support
double-sided RX03 floppies. However,
the boot code is still
a bit stupid and can't boot a monitor
file which is partly at the
end of side 1 and continues onto side 2.
RD53 - Yes out of a bag of scrap
drives I managed to get the remains
of a bump stop out and replace it.
It produced one good
drive which boots RT-11 every time.
I still have a few RD53 drives around
which I stopped using.
I also converted a couple of
Micropolis 1325 drives to
RD53 drives by adding jumper R7. I
really don't use
my PDP-11/83 very much since
Ersatz-11 is really so
much more convenient and my goal for
RT-11 is only
software bug fixes and enhancements.
Jerome Fine