Path: csiph.com!usenet.pasdenom.info!aioe.org!.POSTED!not-for-mail
From: Walter Banks <walter@bytecraft.com>
Newsgroups: comp.misc,alt.sys.pdp11,alt.folklore.computers
Subject: Re: Revamped PDP-11 in Brooklyn
Date: Tue, 20 May 2014 16:45:22 -0400
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RS Wood wrote:

> On Mon, 19 May 2014 23:10:34 +0200
> Paul Sture <nospam@sture.ch> wrote:
>
> > That is very similar to the first PDP I worked on, and coincidentally that
> > was 1978 as well.
> >
> > Ours started out with 64KB, two RK05 disks and 3 VT52 terminals.  By
> > Christmas 1979 we had upgraded it to 192KB, 6 terminals, another couple of
> > RK05s and an RL02.  No tape though, we did our backups to RK05s.
>
> <snippage>
>
> Fascinating to hear from someone who had experience with one of these
> things.  This picture of the sequence of byte-by-byte instructions for
> booting the machine blows my mind.
>
> https://www.flickr.com/photos/osr/14043526294/in/set-72157644327706146
>
> Kind of puts into perspective PC users who are having trouble with
> GRUB2 or think their BIOS sucks, etc.  Here, I'll transcribe it:
>
> LA 010000
> DEP 012737
>     000005
>     177404
>     000777
> LA 010000
> START
> WAIT 1 SEC
> LA 0000000
> START
> .   P4
>
> Wizardry, total wizardry.  I'm in awe.

I just happened to have a PDP-11 instruction list card on my desk
(:  Maybe my wife is correct I don't throw things away )
the original PDP-11 before it was renamed PDP11/20.

For a PDP11 Bootstrap Loader is listed as
-----------
LOC   CONT
-----------
*744  16701
*746     26
*750  12702
*752    352
*754   5211
*756 105711
*760 100376
*762 116162
*764      2
*766   *400
*770   5267
*772 177756
*744    756
*756 177560 (TK)
            or
     177550 (PR)

-----------
 MEM
 SIZE   *
-----------
 4K     17
 8K     37
12K     57
16K     77
20K     117
24K     137
28K     157

I wish I had a nickel for everytime
I keyed a bootstrap into a PDP-11

The UNIBUS was quite easy to interface
to and a friend and I took a prototype
board and a handful of logic to create
a combinatorial logic implementation of the
PDP-11 bootstrap in a midnight to
morning experiment to save us some time.

w..


w..