kermit.columbia.edu/kermit.columbia.edu.tar/kermit.columbia.edu/extra/k278.bwr

Text File | 1988-08-16 | 5KB | 91 lines

Date: Wed 7 Jan 87 02:25:32-EST
From: Charles Lasner <OC.LASNER@CU20B>
Subject: PDP-8 Info

The following information on 12-bit operating systems may be of use to you:

DEC-related systems:
OS/8 (also known as PS/8, OS/12, PS/12 and OS/78 v1,2,3) o.s. for PDP-8 family
OS/78 v4 slightly defective subset of OS/8 which runs on later PDP-8 family
only, but sacrifices some features so it can attempt to run same subset on
VT-278 (also known as DECMATE (I), the (I) added when the II came out)
OS/278 for DECMATE II and III and III-plus. This is a personally-preferenced
version of OS/78 v4 that is the only version available for the later DECMATES
which can be had for nominal cost from DECUS. All OS/8 family systems are
similar, but not identical. K08MIT will not run on DECMATES. It will run on
any of the others, iff the host cpu is a pdp-8, not a DECMATE (v4 can run
K08MIT on PDP-8/E,A,M,F or CESI clone).

COS-310 (formerly COS-300 or just DIBOL-8)
This family of operating systems has earlier versions for all PDP-8 machines
but DEC's attitude is planned obsolescence. The current version only runs on
DECMATE II,III,III-PLUS but earlier versions work on DECMATE I;still earlier
versions run on all PDP-8 family. Conversion programs are available to move
COS STRANGE (EXCESS_237 asciisix-bit) to OS/8 ascii files, so users of
COS-310 depend on the corresponding OS/8 family version.

WPS-8 this has the same checkered history as COS, but many users currently use
all forms of DECMATES, pdp-8 family machines currently with some version of
WPS-8. This includes the very popular VT-78 (looks like VT-52 with a PDP-8
micro board (6120) inside of it and an rx01/02 pair or two below it) which is
compatible, although slower. There exist conversion programs (WPFLOP) to
convert WPS-8 8-bit extended ASCII files to OS/8 and vice-versa. The
conversion involves changing WPS figures (embolden, etc.) into the ascii
character strings that would be carried out on a "dumb" printer. Of course
Wps-8 users depend on K08MIT as well.

NON-DEC systems:

MULTOS, ETOS, OMNI-8
These (incompatible) systems all work on the same principle: virtual machines.
They support an external file system for inter-task communication,backup,etec.
but religiously emulate multiple single-user PDP-8 systems eaven down to the
stand-alone i/o routines (which is awfully inefficient). Several of these
systems support special-purpose utilities at the top level,such as time-shared
editors, slow real-time data collections, etc. Omni-8 is the one I am most
familiar with;it supports all of the above DEC systems in simulation and
they require DEC licenses where applicable.

P?S/8 The Poly Question Society Monitor System (for PDP-8) This system is
the only system that exists outside of DEC's perview and consists of many
novel programs for the pdp-8 for purposes of pdp-8 program development and
application running on a minimal configuration (or more) that starts out
smaller than DEC's minimum configuration (only 4-k yes four-kay! of 12-bit
words are required to run the minimum P?SX/8 configuration, but more is
often required for applicastions,as PDP-8's grow to 1 meg (six-bit bytes)
these days. (MOST are 32k OR LESS!)). P?S/8 is copyright Charles Lasner
Associates, but is offered free to qualified individuals and institutions.
Its file structure is a combination of small fixed-length files with a
six-bit ascii subset, and a varaible - length file structure with a tree shape
vaguely reminiscent of MS-DOS, which supports six-bit and true eight-bit files
(OS/8 has trouble with the eighth bit and is best treated as seven-bit. When
(if K08mmit is fixed, it should be made to rigorously support 8-bit;right
now it only does ascii anyway!). This system is still under constructions
(users are advised to wear hardhats!) and has been since 1968 by various
individuals (most notably Richard Lary of DEC befre he went to DEC at Poly)
I am the chief contributor these days (with a little help from my friends).
It may be notable to you to report KERMIT working on a 4k machine (eventually)

Correction:

In K08MIT, you document it as for OS/8 and RTS8. While we agree about OS/8 in
the above, RTS-8 is another matter entirely. RTS-8 is *not* an operating
system.It is a user - assembled collection of slow real-time tasks with an MCR
routine (RSX-8?) which *can* include support of two OS/8 related tasks. The
first is an OS/8 file task, which allows user tasks to communicate OS/8
compatible file i/o to certain qualifiable (interface can run in real-time) i/o
devices, but not all known devices. When RTS-8 is shut down, the OS/8 user can
search the directory for activity generated during RTS-8 operation. RTS-8 is
run under OS/8 (which is just a loader relative to RTS-8) and returns to OS/8
when it exits (it is really a glorified user program). ITt would be nice if a
version of KERMIT ran under this environment, but it doesn't.  The second is an
OS/8 emulator task. This allows the original single-user of OS/8 to be the MCR
and also be himself (sort of like opser) with no change to his original system.
Due to internal overhead and literal emulation of stand-alone i/o, this
emulated OS/8 enviromnet crawls, just like omni-8,etc.  above, ONLY WORSE!
Technically, K08MIT might run (crawl) in this environment but its utility is
dubious, as emulated interrupts probably can't keep up with 300 baud, much less
1200 baud. (In theory, K08MIT runs at 76.8 Kbaud or less).

Charles Lasner