ICL Personal Computer, 1984

This strange beast is 8088 based, but it is most definitely not a PC.

(Old picture) The computer case contains a passive backplane with seven cards: CPU, FDC, 3 x memory, interface, and serial. In addition to this, there's a board located under the MFM (?) hard drive which controls the HDD.

This computer is obviously meant to drive four serial terminals. I havn't fired it up yet, will do so when I get a chance.

CPU board top view

The CPU board lineup is 8088, 8237 DMA Controller, 8259 Programmable Interrupt Controller, BIOS in EPROM, and a fair amount of glue logic.

The BIOS contains the following text:

ICL Personal Computer (Firmware Vn. 1.4 02 Feb 84)
Copyright (C) 1984, ICL Plc.
    (Johnson-Laird Inc.)

Performing Hardware Self-Test.

Andy Johnson-Laird

Quad UART board top view

The serial board has four 2651 Programmable Communications Interfaces and four sockets maybe for an additional four PCIs? 4 x 1488 and 4 x 1489 gives enough RS-232 for eight ports with RxD, TxD, RTS and CTS, or four ports with full handshaking support.

The PCB mentions RAIR (see also the comp.os.cpm post further down). The 1981 date means this is probably the same board as was used in the earlier 8085-based systems.

RAM board 1 top view

RAM board 2 top view

RAM board 3 top view

The three RAM boards are similar but not the same. At first it looks like boards 2 and 3 are a later design, with provision for parity chips, but board 1 carries a 1984 ICL date, as opposed to the 1981 RAIR date of boards 2 and 3. Board 2 has a number of innovation jumpers, this was fixed for board 3.

All three RAM boards have four banks of 4164s for 256k each, 768k total.

Floppy Disk Controller board top view

The FDC is conventional, with an MB8877A which is basically a WD1793. Also a 1981 RAIR PCB.

(Old photograph) The cable from the interface board runs to the Hard Drive Controller and to a socket on the back of the case. There's not much on the interface board, TTL and one PROM presumably for address decoding. RAIR 1982.

The Hard Drive controller features an MK3880, a.k.a. Z-80. The interface to the hard drive looks pretty much like your basic ST-506.

The cable from the interface to the Hard Drive Controller is also routed to this connector (but I'm pretty sure it's not SCSI).

I think it's clear that the basic RAIR Black Box design didn't change much, ICL just dropped an 8088 in there for this version.

From Google:

  From: Richard Plinston (Richard_Plinston@kcbbs.gen.nz)
  Subject: ICL Personal Computer 
  Newsgroups: comp.os.cpm
  Date: 1993-10-13 15:31:14 PST 

In message <<750453260snz@number8.demon.co.uk>> mjc@number8.demon.co.uk
>circa 1981/1982 from a rubbish skip outside a software house.
>We wonder if anyone knows anything about this machine, such as what 
>the OS is (CP/M or Unix) and what terminals attach to it.
>We have determined that it switches on and the hard disk apparently boots. 
>We still have to attach a terminal. I have access to Wyse 50 and 60 
>terminals and wonder if these would be suitable. Thanks in advance
>for any info.
ICL introduced the ICL PC (now called PC/1) in about 1981. it was a
rebadghed Rair Black Box and ran CP/M 2.2 or MP/M depending on model.
some had 4 serial ports for terminals, 256Kb memory, 5 or 10 Mbyte
discs.  40track floppies.

Identifiable by dark brown front panels.

Later they redeisgned these as the PC/2 with 8085AH2 CPU, boxes were
beige.  Again CP/M 2.2 and MP/M 2, memory to 512Kb, 10Mbyte. 80 track

In about 1984 they brought out 16bit machines with 8088, running
CCP/M 3.1 (plus DOS mode from 3.2).  Up to 4 terminals, up to 1MByte.

Later machines were Quattros with 8086 processors and 50MByte drives,
running CDOS 4.1 (which could access DOS directories on floppies),
Quattro-XMs which ran CDOS 5.1-XM and could utilise bank switched memory, 
up to 8MByte memory.  The last models had 80286 and 90 or 160MByte SCSI

In the mid-80s they were the most cost-effective multi-user system, some
are still in use.  i have several clients still using them, but I am
trying to replace them, mostly with MultiUser-DOS, the direct descendant
of CCP/M-86.

The terminals are best if they emulate an ADM-31.  Each terminal can
be set to support 4 tasks with CCP/M or CDOS.