Re: FW: [pups] A bootable disk image for a PDP-11/34? - TUHS

1 Feb 2001

This is a real stretch for my brain, but I seem to recall that the ";" that
appeared in ";login:" in the 1970s was sort-of "bleed-through" from an
escape sequence that was intended to do cursor positioning and/or screen-clearing on some
terminals... or something like that... therefore its absence would not necessarily be
significant on different hardware.

    -Bill Mayhew, UNIX mangler emeritus

...
  From: owner-pups(a)minnie.cs.adfa.edu.au
 [mailto:owner-pups@minnie.cs.adfa.edu.au]On Behalf Of Carl Lowenstein
 Sent: Thursday, February 01, 2001 12:35 PM
 To: iking(a)microsoft.com
 Cc: pups(a)minnie.cs.adfa.edu.au
 Subject: RE: [pups] A bootable disk image for a PDP-11/34?

  From iking(a)microsoft.com Tue Jan 30 15:27 PST
2001
 From: Ian King &lt;iking(a)microsoft.com&gt;
 To: "'Ken Wellsch'" &lt;kwellsch(a)tampabay.rr.com&gt;om>,
         Carl Lowenstein
      &lt;cdl(a)mpl.ucsd.edu&gt;
 Cc: pups(a)minnie.cs.adfa.edu.au
 Subject: RE: [pups] A bootable disk image for a PDP-11/34?
 Date: Tue, 30 Jan 2001 14:38:15 -0800

 Ken, I tried using that image and gunzip told me there was a crc error; it
 wouldn't unzip it.  (I downloaded it three times, just in case there was a
 transmission error -- twice by ftp, once by http.)  I've also tried the
 "Dennis" images, which are supposedly straight RK05 images; E11 won't
boot
 'em.  One issue on which I'm not clear: where is the boot address?  Stuff
 at
  loc 0 doesn't look like boot instructions.

 If I could get an image to run in an emulator (as I mentioned, I'm running
 E11 from DBit), I'd write some cheesy little loader to bring it down the
 serial line (I already have it sketched out); but until I can at least get
 one to boot in the emulator, I'm reluctant to spend the hours (at 9600  baud)
  to spray it onto a disk.  <sigh>  
 Well, as some response to this challenge "get an image to run in an
 emulator",
 I visited Bob Supnik's Computer History Simulation Project web page

     <www.tiac.net/users/mps/retro/>

 and followed the links to the sources for SIMH v2.5a and to the Unix V6
 disk images.

 I read the documentation file "simh_doc.txt", and compiled the
 simulator.  Then I read "simh_swre.txt", unpacked the V6 images, ran
 the simulator and attached the three RK05 images to it, and booted
 RK0.  All according to the instructions.

 I got the bootstrap prompt "@" to which I typed "unix" and it came
up
 with a "login:" prompt, to which I could log in as root, and do things.

 It's not quite the same V6 image that I remember from the olden days of
 loading onto an 11/40 from magtape.  The login prompt seems not to be
 ";login:" as we still see on the Usenix magazine.  dmr's account seems
 to have vanished but ken's is still there.  And that's how I spent a
 few hours last night.

 In case it matters, the underlying hardware/software platform is an AMD
 K6-3 running Mandrake 7.1 Linux.

     carl

         carl lowenstein         marine physical lab     u.c. san diego
         {decvax|ucbvax} !ucsd!mpl!cdl                 cdl(a)mpl.ucsd.edu
                                                   clowenstein(a)ucsd.edu 

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To: mayhew(a)altavista.com
Subject: Re: FW: [pups] A bootable disk image for a PDP-11/34?
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 pups(a)minnie.cs.adfa.edu.au
...
  From mayhew(a)altavista.com Thu Feb  1 14:31 PST 2001
 Date: 1 Feb 2001 14:30:43 -0800
 X-Sent: 1 Feb 2001 22:30:43 GMT
 To: cdl(a)mpl.ucsd.edu
 From: Bill Mayhew &lt;mayhew(a)altavista.com&gt;
 Cc: pups(a)minnie.cs.adfa.edu.au
 Subject: Re: FW: [pups] A bootable disk image for a PDP-11/34?

 This is a real stretch for my brain, but I seem to recall that the
 ";" that appeared in ";login:" in the 1970s was sort-of
"bleed-through"
 from an escape sequence that was intended to do cursor positioning
 and/or screen-clearing on some terminals... or something like that...
 therefore its absence would not necessarily be significant on different
 hardware. 
Oh, yes.  I was just hiding my previous knowledge.  The ";" and ":"
in
the login prompt were the visible part of escape sequences to control a
Teletype KSR37.  They didn't do anything useful on a VT05 but did show
up on the screen.

Unix Sixth Edition predates the common availability of even the dumbest
CRT terminals.  There are still a lot of TTY37 control codes hanging
around in nroff output.

    carl

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