Is there any info/documentation/manual for the ACT Series 800, which is also the CompuThink Minimax II, out there or does anyone have any of this?
The ACT Series 800 / CompuThink Minimax (the Minimax I and II differ in the type of external storage, as far as I understand this) claims to be upward compatible to the Commodore PET (probably running some variant of Microsoft’s 9-digit BASIC), but adds high-res graphics, which should make this a rather nice retro system to emulate. (I guess, some internals, like the IEEE bus architecture may differ, as well.) – Wo wouldn’t like to “outcomputer them all”? – But I fail to find any data or documentation on this.
PS: The ACT Series 800 was ACT’s first foray into microcomputers, before the much more successful Apricot series. (I guess, the “800” in the name suggests that this is really a repackaged Minimax I, as opposed to the info available, generally equaling this to the Minimax II.)
A couple of things jump out from an advert in BYTE - see below
108k system RAM of which 48k user RAM
16k Basic ROM (possibly includes mini monitor and assembler?)
64 user defined microcoded opcodes available
So a dump of that ROM would be a minimum, and a disassembly might tell us a lot about the hardware. But the user defined microcode, that probably needs a manual or a circuit diagram. Perhaps a visit to a computer museum is the thing.
• THE MINIMAX SERIES COMPUTER IS AN INTEGRATED, COMPACT UNIT CONTAINING THE CPU. DUAL DENSITY DISK STORAGE, 12 INCH CRT, AND FULL STYLE KEYBOARD. WITH SEPARATE NUMERIC ENTRY PAD. ALL KEYS (INCLUDING CURSOR) WITH FULL REPEAT HYBRID 2 MEGAHERTZ 6502 CPU 108K SYSTEM RAM (48K USER) FASTEST FLOPPY DISK ACCESS (24K LOADS IN 4.2 SECONDS) • 16K ROM CONTAINS COMPUTHINK BASIC (AN EXTENDED MICROSOFT BASIC) WITH EXTENDED PRECISION, DOS INCLUDES COMPLETE FILE I/O WITH FULL RANDOM ACCESS, COMPLETE MONITOR WITH DEBUG & TRACE, AND TINY 6502 ASSEMBLER COMPLETE HIGH RESOLUTION GRAPHICS WITH INDIVIDUAL DOT (240x512) POINT SCREEN ADDRESSABILITY FULL SCREEN TEXT EDITING WITH OVERWRITE, INSERTION OR DELETION SPLIT SCREEN/WINDOW MODES INDIVIDUAL FIELD EDITING WITH FIELD PROTECT AND AUTO SKIP TO NEXT FIELD DISK STORAGE SYSTEM TRANSFERS AK PER SECOND WITH AUTO VERIFY AND PARITY CHECK 12 INCH CAT-64 CHARACTERS BY 30 LINES. UP TO THREE PROGRAMMABLE CHARACTER FONTS FOR LANGUAGES OR SPECIAL CHARACTERS SWITCHABLE 110 OR 220V OPERATION… HYBRID CPU IS MICROPROGRAMMABLE WITH 64 USER DEFINABLE OPCODES. CHOICE OF 800K OR 2.4 MEGABYTE DISK STORAGE FULL SERIAL RS-232C PORT WITH PROGRAMMABLE BAUD RATES AND MODEM CONTROL SIGNAL • DEDICATED DISK PORT PRINTER PORT SUPPORTS PARALLEL COMMERCIAL PRINTERS 24 PIN I/O USER PORT PAGEMATE DATABASE AVAILABLE PLM COMPILER AVAILABLE BUSINESS PACKAGES AVAILABLE COMPLETE DIAGNOSTICS & SCHEMATICS INCLUDED COMPLETE USER MANUAL INCLUDED
I guess, according to the claim of PET compatibility, much of this would be similar to what had been implemented on or for the PET. It would be interesting, how similar. (E.g., how compares the on-screen editing with definable windows to Commodore’s screen editor for BASIC 4.0?) And then, there’s, of course, the difference in screen dimension and that everything is addressable and to be addressed by x/y coordinates.
The “hybrid CPU”, which is the same time 6502 compatible and has 64 user-definable microcoded instructions, is something totally different. Is this a bit-sliced processor, similar to what may be found on minis at the time? Do we know of such a processor on a single chip? (Or is this actually more a mini in disguise?)
PS: Or is this just macro code in conventional 6502, stored in some special RAM, and some of the unused/unofficial instruction codes are intercepted? But I can’t really imagine a great boost from this. (Maybe, this is why this isn’t as famous as we may expect from reading about this?)
It’s a good question as to what that might be. The CCH has a photo of the innards - quite possibly by arrangement one could take good photos of each board. (Photo at this link shared upthread)
But I’m baffled by how few of any documentation (besides a few ads) is available. I don’t think that I have encountered such a void before. This machine has been sold in 3 types of packaging on at least 2 continents – and there’s apparently nothing left. It was interesting enough to impress ACT, a serious systems consulting firm, people actually owned this and had manuals, there must have been user clubs and newsletters, but…
