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Terry Yager
April 28th, 2005, 11:12 AM
A PDP-8 compatible DECMate II system is being offered on eBay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1247&item=5191131766&rd=1

--T

Chris2005
May 3rd, 2005, 04:26 PM
iww, looks like a rainbow, smells like a rainbow *musty*, but has a pdp-8 processor. iww. lol

Terry Yager
May 3rd, 2005, 05:33 PM
Sold cheap, too...

--T

Chris2005
May 4th, 2005, 04:06 PM
yeah. Someone wants to ship me one though, free other than shipping, but it's not really my cup of tea *blech*. Actually, I thought the thing had some sort of Harris processor. But maybe that's synonymous w/pdp-8.

Allison
May 5th, 2005, 06:17 PM
yeah. Someone wants to ship me one though, free other than shipping, but it's not really my cup of tea *blech*. Actually, I thought the thing had some sort of Harris processor. But maybe that's synonymous w/pdp-8.

Yes, Harris and Intersil both made the CMOS chip level versions of the PDP-8. There are two flavors of the CHIP the 6100 wich is bare-8 or differntly put no extended address (EMA) though there was the MEDIC
chip to add that. the latter was the 6120 and that was a faster version that also had EMA integrated.

The DECmate-II and III are 6120 based. The basic differece is the III is smaller, has a few more extensions (CP/M APU, DOS APU, Hard disk).

The DECmate series was built to run WPS, Word Processing System and
in the later version that included a list processor and spread sheet.. Another OS that runs on it is called OS278, it's a DECmate IO tweeked
version of OS/8 a complete and somewhat multitasking/ timesharing OS.
OS278 is small enough to run off the RX50 floppy (400KB) with space available.

What makes the DECmate interesting is the 61xx sseris cpus really had two distinct address spaces that didn't exist on the real PDP-8. One space is the usual PDP-8 operation, the other is called CP (control pannel) and was intended for a software front pannel that was not in normal operating space. The DECmates used this space for what was called internally "slushware" that was to make things like the CRT, Keybaord and other
devices look simple to the OS and also provide services and user configuration. The other charateristic is it has twice the ram of any real pdp-8 as well (EMA only got to 32K words) and these have more.

It's a very unique box. Unlike any micro and programming one is
both interesting and a challenge as the mindset that works for
any of the more routine cpus does not apply. Yet the instruction set
extremely RISC like(excluding IOTs about 47 instructions).

Notes: never buy one without a LK201 keyboard, Vr201 monitor and basic cables (keyboard, monitor). Between the DECmate-II and DM-III there
anything but rare by production numbers though many have been abandoned or worse.

Hope this answers a few questions.

Allison