From: lasner@watsun.cc.columbia.edu (Charles Lasner)
Newsgroups: alt.config
Subject: Re: alt.sys.pdp8
Date: 4 Sep 92 17:53:47 GMT
Reply-To: lasner@watsun.cc.columbia.edu (Charles Lasner)
Organization: Columbia University

In article <1992Sep4.102716.5020@pollux.lu.se> magnus@thep.lu.se (Magnus Olsson) writes:
>Charles Lasner (lasner@watsun.cc.columbia.edu) recently proposed the
>creation of an group called alt.sys.pdp8 on alt.folklore.computers.
>Since I haven't seen his proposal here on alt.config, I'm taking the
>liberty of reposting the relevant portion of his article here. 
>
>>send e-mail to pdp8-lovers-request@ai.mit.edu to get on the DEC old iron
>>mailing list mirror which is pdp8-lovers@ai.mit.edu  I would also like someone
>>to create the newsgroup alt.sys.pdp8 to be an expansion on the activities of
>>the mail mirror so we can reach a wider/different audience.  The activities
>>on this list are geared to all aspects of PDP-8 hardware and software, and
>>also all other similar vintage DEC machines.  (The PDP-10 and -11 people
>>may want to argue over which architecture is "second" on the list, but the
>>main point is that all are welcome, especially when discussing things like
>>peripherals, which tend to cross all hardware platforms, etc.)

Just to embellish a few points:

PDP-8's and similar machines are actually quite popular, usually used by those
sometimes described as either hobbyists or tinkerers, but with a difference:
most are attracted to various asthetic aspects of the architecture.  The
proof of this is that since some of the hardware per se is rather "ancient"
yet people are hardy enough to attempt to overcome the problems that don't
come up in newer designs.  If you wanted a piece of an IBM-PC compatible,
you just go to a store and buy it, but if you want a serial board for a
PDP-8/e, you have to seek out individual users willing to swap/sell/give away
what you need.  The stuff is "distributed" in a very skewed manner because
most of those interested in the -8 have hoarded as much of things as they can
get hold of.  I give away original copies of the PDP-8/e Random TAD exerciser
diagnostic writeup because I'm "down" to *only* 14 copies left of it.  Yet
there are interested parties, who stumble across my existence only because
they found my name on another newsgroup, who want some of this stuff.  Giving
us a fit and proper newsgroup would organize all of these "word of mouth"
efforts.

Until only a few years ago, the PDP-8 generally didn't have enough software
to allow users any access to newsgroups.  There was no standard terminal
emulator for it, even though most machines have all the necessary hardware or
are lacking only a readily available serial port and cable.  Today, things
are quite different:

I am the author of Kermit-12, an implementation of Kermit for all of the
DEC 12-bit machines of the PDP-8 family, from the classic 1965 PDP-8 through
the DECmate III+ of 1987-1990.  Suitably configured PDP-8's or any VT-78 or
DECmate can run the program as provided, or with trivial customizations.  It is
freely available from watsun.cc.columbia.edu as part of the Kermit distribution
and can be acquired via anonymous ftp, etc.  The package includes a "bootstrap"
method so that trivial programs (40-odd words) can be typed in to allow
download from other machines using a specially (and printably) encoded loading
format that doesn't require a protocol.  (It loads directly into memory only.)
Thus, PDP-8's are getting Kermit up without any requirement of having a Kermit
to begin with.  Such machines can access the "outside world" of usenet, etc.
and are thus now "main-streamed".

As might be expected, binary programs in encoded form will tend to be
propagated across such a group, and that conjures up net.fears regarding
huge file transfers strung across many sequential articles, and all of
the consequential bandwidth associated with the problems of reposts so mr.
so-and-so can get part 14/57, etc.  Let me assure you that this isn't
what happens at all:  Typical PDP-8 programs are about 25 "pages" in length,
where a page is 128 words 12-bits each.  Expressed in 8-bit bytes, that's a
total of 4800 bytes.  I have already written, and distributed via anonymous
ftp from watsun.cc.columbia.edu as part of the Kermit project, an encoding
scheme conceptually similar to uuencode, but more robust, based on a 5-bit
encoding with checksumming and any-value data repeat compression.  (PDP-8
binary often repeats specific non-zero values, and the repetition is only
noticeable when viewed as 12-bit sequences; .BOO format for example is
unsuitable for noticing this form of redundancy.)  Overhead for using the 
encoding to printable is worst case 60%, but often less due to the compression.
Thus, a worst-case post for a typical program is 7680 bytes total.  Further,
the protocol is immune to case-conversion, white-space contamination, and any
">From" disease.  Since it includes imbedded command info for file starting and
ending, as well as comments (some auto-generated by the prevailing utilities),
there is little confusion regarding what portion of a post should be kept,
etc.  All of these factors should encourage good receipt of the file, and
keep reposts to a minimum.

There will be some posting that addresses the PDP-8 portion of the DECmate
series where the issues are common with the older PDP-8, PDP-12 and VT-78
models, such as a unified operating system currently being developed from
the "ashes" of all of the previous slightly incompatible ones, but this isn't
a forum where DECmate WPS users are attempting to ask questions such as how do
I get a document index for the system diskette (answer: it has a dummy document
index in case you ever accidently did this).  WPS questions other than
incidental will get directed to comp.sys.dec.micro if necessary.  However,
hardware questions would be welcome, especially since some of the peripherals
involved in DECmates can be used on some of the other machines DEC doesn't
classify as micros.  The PRO series also shares some of this problem as well.
Moreover, comp.sys.dec.micro posters consider themselves Rainbow people
primarily, since that's the only machine that truly is *only* a micro and
only from DEC.  (DECmates are PDP-8's and PRO's are PDP-11's, even if
considered bastard step-children; this group will take them in if necessary.
Moreover, they run PDP-8 software and PDP-11 software, not CP/M or MS-DOS
which are for micros.  This would be a DEC minicomputer group in the original
sense, *not* micros and certainly not VAXes or Alphas either.)

A point of discussion will be the acquisition of an ftp-capable archive site
for a lot of "little" files, since there are potentially several thousand
programs to be considered, the vast majority the size I discussed or smaller.
Hopefully, a newsgroup will attract worthy volunteers for that project.

cjl
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