7th Edition on a real PDP-11/23+

Bob Armstrong bob at poco-adagio.santa-clara.ca.us
Thu Jan 23 15:20:45 AEST 1997

>Bob, firstly if you can write down the details of how you got the
>image installed & running on the 23+, and email it to the mailing list
>(oldunix at minnie.cs.adfa.oz.au), that'd be great, as I archive the mail.

  It was actually quite simple.  Bob Supnik's RL02 file is simply a byte
for byte dump of a pack.  That is, it's just sector 0, head 0, cylinder 0
followed by sector 1, head 0, cylinder 0, ... then all the sectors of
head 1, cylinder 0, then cylinder 1, etc.  There are no overhead bytes
in the file an no interleaving is used.  RL02s have 40 sectors of 256
bytes each per track, two heads, and 512 cylinders for a total 10240K bytes
per disk (which happens to be exactly the size of Bob's RL02 file :-)

  You want to be careful about bad sectors, since RL02s do bad block
replacement at the device driver level.  If your pack has any bad sectors
that aren't at exactly the same spot as bad sectors on Bob's original
pack (not very likely!), then this isn't going to work.  Fortunately
error free RL02 packs are relatively easy to come by.

  Anyway, since the only other RL02 that I have access to is on a VMS
system, I had to write a little program for VMS to load the disk using
physical I/O.  I'd be happy to make this program available if anyone
wants it.

  Once you have the pack loaded, you can just mount it on a 11/23 and use
the RL02 hardware boostrap.  The Unix boot will start and print a "@" for
a prompt.  Reply by entering "unix" and carriage return, and you'll see
"mem=205376" followed by "SINGLE USER LOGIN:".  Enter ^Z and Unix will
start timesharing, then you can login in using root with the password "pdp".

  I had two problems in this process.  First, I didn't know about the
Unix bootstrap program (I'm afraid I've never used Bob's emulator!), and
when I saw the "@" I just blindly assumed I'd been dumped back into ODT.
Fortunately Jim Carpenter was kind enough to educate me about this.

  Second, Unix would hang up as soon as I started timesharing.  This
turned out to be because my LTC in the 11/23 wasn't working, which doesn't
bother RT11 at all but it does hang Unix.  After I repaired the hardware
everything ran fine.

  If someone has a PDP-11 with a RL02 drive and no way to load V7 on a
pack, I am willing to do it if you send me a blank RL02.  I believe the
SCO license allows this so long as:

	1) I don't charge for the service
	2) You certify that it is for non-commerical use
	3) I include a printed copy of SCO's license

Note that this kernel supports only RL02 drives, so unless your -11
has a RL02 drive this system won't work.  RD5x and RA8x drives won't do.
A similar procedure would probably work with the RK05 images, but I
don't have the hardware to try.

>Finally, many of the members of the PUPS mail list are covered by
>source code licenses, so if you can tell us what device you require,

  I have a 11/23, DLV11J (4 lines), RL02/RLV11, TU58 (on one of the
DLV11 ports), RX02/RXV21, and a TSV05 9-track tape.  The TSV05 is
TS11 compatible, and I'd especially like to have support for it.
Bob's kernel supports MASSBUS tapes, but not a TS11.

>I'm sure someone can build a kernel for you. I wonder if it's legal to
>ship a kernel which has device drivers not in Bob Supnik's disk image?!

  SCO's license seems to cover all PDP-11 binaries for 7th Edition Unix,
and it doesn't seem to say anything about their origin.  Of course,
I'm not a lawyer either.


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