![[PDP-8 front panel]](8f_panel.jpg)
This page Last updated Sept 17 2009. To email me or to order, see
see my ordering Web page for my email addresses. My other DEC stuff is on this linked Web page.
My PDP-8/F which was acquired from Princeton University several years ago. I'm j-u-s-t starting to pay attention to it in early 2009, thanks to my colleague David Gesswein.
PDP-8/F case view from the top. IN this top inside view of my PDP-8/F, you can see I have one backplane of 20 slots (5 blocks of four slots). The front panel is in "front". Behind the backplane is the power supply, in its black box with a small white connector sticking out. Space to the side of the backplane is not photographed, it extends from the back of the hex-width front panel to the back of the case. Typically, for more boards, another "expansion box" with a quad-width or hex-width backplane and power supply would be attached to this chassis.
Cards in my PDP-8/F, front to back
-- KC8F? - programmer's console (lights and switches) -- M8330 - KK8E Timing board (system clock) -- M8340 \_ optional KE8E EAE board 1 -- M8341 / optional KE8E EAE board 2 -- M8310 \_ KK8E CPU control -- M8300 / KK8E CPU registers -- M837 - KM8E or MC8E extended Memory & Time Share control -- empty slot -- M8655 - RS-232, 9600 baud TTY control, UART -- empty -- "blue tabs" board, Data Systems Design (later Qualogy) DSD 2131A-5, see below -- empty -- brown tab board, no clear brand, analog data collection. -- M849 - KK8E RFI shield -- empty -- empty -- black tab board, CESI brand board, prbably VM816 16K? memory -- M8320 - KK8E Bus loads
Identifications above based on Omnibus Modules listing by Douglas Jones at the U.of Iowa. I've not verified the options (KKxx descriptions). A brief description of the 8/F Omnibus is at this Web site.
I have not examined it in detail. Here's some possibly relevant links. This PDP-8 FAQ entry says "The OMNI-8 operating system supported the enlarged PDP-8 address space of the CESI (Computer Extension Systems Inc) memory cards...". That led me to an UMN .edu IT department? Web site full of documents.
A document from umn.edu (University of Minnesota, USA) was a CESI VM816 product brochure. It describes a 4K to 16K memory board which looks like mine. Neat!
The Non-DEC blue-tabs board I have in my 8/F is a "DSD 2131A-5" "PDP-8 Interface Board"
-- with blue paddles, quad width, all TTL small chips
-- one 20-pin connector w/9 active pins 10 gnds
-- device code 8,6,5,4,3 jumpered (device code 20? 57?)
THere are 5 rows of 8 or 9 TTL-type 14/16 pin chips. The 20-pin IDC connector has one row of ten grounded, the other row only 9 pins are in use. The text in quotes appears on the board.
David Gesswein of pdp8online.com says "[his own] controller is labled DSD A/2131-6. It looks like this is the controller for DSD [brand] 8" floppy drives." I'll find out more in due course. Here's David's page on the DSD product for the PDP-8. DSD's drive used an 8085 "formatter" board to run their drives via the DSD interface. Doug Jones's PDP8 site also mentions the DSD drives. Bitsavers has DSD manuals including a DS 440-480 series drive product manual, with a 2131 model PDP-8 interface board.
In April 2009 at the Trenton Computer Festival, I picked up this PDP-8 version of the RX02 floppy drive, from Mike Connor of NY The photo is on-site at TCF. Just goes to show, you can still get serious computing iron at TCF!
Among my core memory collection, in May 2009 I stumbled across this pair: a H219A core memory card and attached G649A Core x-y driver & sense/inhibit card. Don't know if they work of course; and "pdp-8.org"'s list of modules says this pair is too slow for an 8/E" and presumably for my 8/F.
However Philipp Hachtmann of Germany, a PDP-8 owner tells me his Lab8/E is running a H219A on an extension box, and encourages me to consider similar options.
From the Web, I see that some other PDP-8's have:
# M865 - 20ma, 110 baud TTY control # M869 and M885 - Point plot display system # M840 - High speed paper tape reader and punch # G227, G619 and G104 - Core memory system, 4 k words (green handles) # G227, G619 and G104 - Core memory system, 4 k words (green handles) # M832 - Bus loads
Copyright © 2009 Herb Johnson
