PiDP-8/I Software

OS/8 V3D Device Extensions
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The OS/8 V3D Device Extensions kit (product code QF026) was released in December 1978. It was created to support the newest PDP-8 hardware:

This distribution contains software updates:

The OS/8 V3D Device Extensions User's Guide can be found in Willem van der Mark's PDP-8 doc archive, under OS/8 - Device Extensions - User's Guide - December 1978 AA-D319A-TA.pdf. or on the pdp8 doc archive at devextug.doc -- OS/8 Device Extensions User's Guide

The release notes can be found on at devextrn.doc OS/8 Device Extensions Release Notes .

Details on how the KT8A Memory Extension hardware works, physically and programatically, can also be found at Willem van der Mark's site: ... Emulator.128KMemory/EK-KT08A-UG_jul78-ocr.pdf.

When reference is made to PAL8 version 13, that version originally came from this kit.

The distribution DECtape for this kit, part number AL-H525A-BA has not yet been found. The PDP-8 Software Components Catalog July 1979 gives no part number for a Source DECtape distribution of this kit. There is an RK05 source distribution, part number AN-H529A-SA. However, plausable source and binary have recently been found!

The binaries were on someone's local hard disk and not published to the net anywhere I could find. Sadly those binaries did not include the DECtape's system area, and so the updated version of the OS/8 Keyboard Monitor, Command Decoder and ODT seemed lost until a tape could be found. It appears that the original source of these .en files is Johnny Billingquist's site, ... dectape1.

Then, however, a self-extracting archive called, os8v3f.exe was found on a mirror site of, [ ... fromhichols][rtknicnols]. Mainline didn't have it, perhaps it was purged because of its .exe extension. The archive is also available directly from ... fromnichols, but at slow speed.

When that archive was extracted, the manifest of source files corresponds exactly to the manifest of binaries in the Extensions Kit file archive are present. This looks quite promising for a future project to upgrade to OS/8 V3D with the Device Extensions software, and to create system packs useful even on PDP-8a hardware with 128K words of memory!

After comparing sources found for OS/78, and OS/278, as well as Willem van der Mark's locally modified sources labeled OS/8 version 4, I have moderate confidence that these sources will enable validation and integration of most, if not all the OS/8 V3D Device Extensions functionality.


This validation has been done with regards to FUTIL.

The MACREL v2 tape shipped with version 8A of FUTIL. That was necessary because V2 of MACREL supported the latest memory expansion, and so the OS/8 Core Control Block format needed to change.

FUTIL version 8A integrated patches for FUTIL version 7 into the source. Finding those patches in the version 8A source strongly increased my confidence in those patches.

Unfortunately the FUTIL.SV verson 8A executable was saved incorrectly and then shipped. The Core Control Block setting and starting address were mis-specified. So FUTIL version 8A hangs when run under BATCH.

The April-May 1979 issue of PDP-8 Digital Software News contained patch 35.13.1M which fixed this problem and upgraded FUTIL to version 8B. I've confirmed both the problem and the fix.

Currently if you opt in to having MACREL on the system packs, you get MACREL v2 and FUTIL version 8B. If leave MACREL out, you get FUTIL version 7. The automated pack builder recognizes that the version 7 patches won't apply to version 8, and fails to apply them. The research I did on the OS/8 Device Extensions kit and on MACREL increased my confidence about the FUTIL version 7 patches.

See also our documentation on the MACREL integration and [our documentation on applying OS/8 patches][patchdoc].


Copyright © 2017 by Bill Cattey. Licensed under the terms of the SIMH license.