Accessing a TK50 or TK70 from RT
js at cimmeri.com
js at cimmeri.com
Sun Jun 12 13:18:49 CDT 2016
On 6/12/2016 12:00 PM, Rod Smallwood wrote:
> On 12/06/2016 16:19, Jerome H. Fine
>> >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
>> 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
> Thanks Jerome
Trim on long bottom posts, please.
Especially if there's nothing
interesting added at the bottom.
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