Executive Summary: Very Cool.
Ok, the adventure is nearly complete, the solutions are found, all that is
left is to collect the crystals at the back of the cave. Recapping the
RT/HT-11 saga ...
Overview, I've been recussitating an H-11 with dual H27 8" floppy drives
into working condition. This constitutes the first complete working example
of a PDP-11 in my collection. The system consists of a M7270 w/FIS,
M8044-Dx, H-11-5 serial, H-11-2 parallel, and H-11-Z floppy card. This
system was picked up at a local auction in two lots (one the H11 the other
the H27), the cable to the H27 had been cut off.
After taking apart the system, verifying the operation of the PSU, I put
together the minimum system (CPU, memory, and serial card) and powered it
up. I got the ODT prompt and that was cool. But I had no software for the
machine.
I then saw an advertisement for an H-11 with software that was near by and
asked if I could copy his disks. He said ok, and off I went box of disks in
hand. Only to find they were the wrong type. I scrounged a couple of mangy
disks and managed to get the HT-11B distribution disk and a disk called
"DCOPY" copied. The disk labelled DCOPY also included FORMAT so this was
the disk to have.
Next I got hold of the correct format disks from a fellow list member, and
formatted them on my system. After formatting I tried to Dcopy them and
sometimes it worked and sometimes it didn't. I suspected my drives.
Round 2 with the H-11 software owner and I format 10 disks at his place and
dcopy 10 volumes of software. One of which is the HT-11 distribution
(RT-11V10A). Encountering problems I tried the PIP command "/K" which
Megan's note described as a bad block scan. When I did this I found _lots_
of bad blocks on the disks. Very weird! The disk surfaces looked fine but I
doubted Control Data Corp was going to honor their 5-year warranty :-)
So I came home again late. At home I took the worst disk and used a
tape/video demagnetizer on it and then tried to reformat it. Half the bad
blocks went away! (now down to 12). A few more rounds of this and I finally
got the technique perfectly.
Disk Demagnetization:
Take a stack of 1 or more but not more than 5 disks and
place them on a flat surface.
Run a demagnetizer horizontally and vertically over the disks
starting beyond the edge of the disk, crossing the disk, and then
passing over the opposite edge.
Hold the Demagnetizer about 1/4" above the disks and move it
around clockwise and anti-clockwise several times, then while
moving it in circles, slowly lift it up until it is about 12"
above the disks and turn it off.
The whole operation should take about 20 - 30 seconds.
Once I did this, the disks would format and scan with zero bad blocks and
zero retrys (no marginal blocks either).
To initialize a disk in RT/HT-11 (ver A or B) the following steps are used:
1) Format the disk.
2) Run PIP and type "DX1:/Z" (this will ask for confirmation)
3) From PIP type "DX1:/K" (this will scan for bad blocks)
If you get through step 3 with no bad blocks and no retries you have a
solidly formatted disk and it is ready for use.
Another mystery was some of the programs on the disk, in particular:
MACRO.SAV
ASEMBL.SAV
EXPAND.SAV
Because on my disk MACRO quit into ODT and ASEMBL failed to interpret the
macros correctly.
In the DOC file for DCOPY that the author wrote, he gave the steps to
reassemble DCOPY.MAC and they were:
.R EXPAND
*DCOPY=DCOPY
.R ASEMBLE
*DCOPY=DCOPY
.R LINK
*DCOPY=DCOPY
It turns out that EXPAND is the "macro" part of the macro assembler, and
MACRO is the RT-11 MACRO-11 assembler from V02 (it crashed on the V01 disk)
Now with good media in hand, I make one more pilgrammage and I should have
everything I need to really enjoy this system.
Thank you everyone for your help, it has been invaluable!
--Chuck
Received on Sat May 01 1999 - 17:04:48 BST
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