View Full Version : Mostek computer of some sort

June 26th, 2003, 07:59 PM
Hello all,

Iíve come into possession of a Mostek computer (Iím pretty sure itís a computer anyway) with a pair of 8Ē half height floppy drives (Shugart 860s) and three cards.

The cards are roughly 6x4 inches with a 56 finger edge connector on one of the long ends and various connectors on the opposite end (Iím not familiar with these). They are labeled MDX-FLP2 (plugged into the drives Ė obviously a floppy controller), MDX-SIO (almost certainly a serial IO card) and MDX-CPU3. The last card is the processor card. The main chip appears to be a MOSTEK Z-80 clone which is labeled MK3801N-4, Z80-STI AND ENG. PROTO. There are 8 4564s for 64K RAM on the card along with what are either connectors for serial and/or parallel ports.

The whole box is about the size of a typical rack-mount machine with a plastic case around it. Most parts are tagged as Mostek and most date codes are from the middle of 1982.

Of course it came without software or documentation.

Is anyone familiar with this machine? Does anyone have a boot disk, other software or documentation for it?



September 8th, 2003, 11:27 AM

We use a Mostek MDX-CPU2 with several SIO2 cards, one 16k Ram board, interrupt expander, rack driver and a few other that I can't remember at the moment. The MDX-CPU2 has 6 sockets for ROM's and they contain the software. The SIO2 has two serial ports that can be configured via the on board links for various speeds and DTE or DCE and the IO address of the board. The CPU is a Mostek version of a Z80 running at 4 Mhz.


September 8th, 2003, 05:56 PM
I have a Mostek Z-80 chip sitting in my drawer. Let me get the serial num.

mk3882n-4 (z80-ctc)

May 13th, 2005, 03:50 PM
MOSTEK was a spinoff deom Texas Instruments in athe mid 60's or maybe a little later. I have had a couple knock don-drag outs with some people who assumed that the acronym MOSTEK was a shortened name for MOS Technology, the company that designed the 6502 (or maybe stole it from Motrola as Motorola claims) Anyway thsey were one of the first to be licensed by ZILOG to second source the Z-80. I have always thought that the computers they made were intended to be used in the same kind of appllications that the INTEL computers were aimed at. This was generally, the tool used to develop microprocessor based products,
For example, one of Adam Osborne's books was a text on how to incorporate the 8080 into a product to reduce the count of standard IC components. What was so fascinating about the book was that he used a Qume Daisy wheel printer as the example. And he used THREE 8080 microprocessor chips and associated support chips to implement all the functions that the standard machie was capable of which required three or four big printed circuit boards full of TTL and driver chips, while in his example it only took two boards about half the size. What got me about it was that we were getting all of the power of most CP/M computers with just one microprocessor!

Terry Yager
May 13th, 2005, 07:04 PM
I've always been impressed with Sir Clive's 4-chip Z80 designs. Imagine a full-function computer on a board not much bigger than a 6x9 index card, and this in like 1980-ish.


October 15th, 2008, 02:44 PM
I know this thread is very old but I have a Mostek here that I have rescued out of the skip (dumpster) at work.
It has a Z80 CPU and two full height 8" floppy drives and all housed in a VERY heavy solid metal case. Just a shame it has NO disks for it.


As you can see it has multiple connectors at the back for printer/terminal and debug.

nige the hippy
October 15th, 2008, 03:38 PM
Blimey! you still have those sort of bits and bats going into your skips, I haven't seen anything that pre-historic dumped in ages.

I gather you're UK.

Good grief, it's taken me ages to type this, on an ex-dump at/xt switchable keyboard, because just today I realised I'd run out of ordinary PS2 compatibles

Terry Yager
October 15th, 2008, 05:26 PM
Lovely box, what's it look like on the inside?


October 16th, 2008, 10:37 AM
Well, sun has gone down here in the UK. But I will pull it out of storage tomorrow and post some pictures of the PCB's

October 16th, 2008, 10:50 PM
I've got spec sheets for some of the MD modules, FWIW:


February 18th, 2009, 02:46 AM
Hi Stevebasset,

Yours is an old post I know but the pictures you posted of your Mostek computer look extremely similar to one that is being sold on ebay (UK) at the moment (Feb 2009).


So I'm guessing you had no luck in getting it working then? How far did you actually get with it? Is it worth buying?

February 22nd, 2009, 04:29 PM
Yup. Its mine alright! It does need some work as they say. But yes, I honestly think it is worth saving. I have put it on eBay at a high price mainly for some enthusiastic to have a go and also to put off the gold miners.
I also think that it is very, very rare. Some boards are dated 1977 and looking at Mosteks wikipedia entry it looks like the computer side did not last long.
The system does boot to some kind of prompt but I just dont have any time to try it any further.
Oddly digging about on the net I have found some UCSD Pascal for it BUT only if I can (somehow) write it onto the 8" disks.


February 22nd, 2009, 06:14 PM
Major LOL, 74 pounds!!!! Makes the Cromemco Z-2 look like a cheap aluminum soda can. My back hurts from just looking at the UK ebay listing now. I am gonna sue!!

February 26th, 2009, 02:25 PM
Yup. Its mine alright! It does need some work as they say. But yes, I honestly think it is worth saving. I have put it on eBay at a high price mainly for some enthusiastic to have a go and also to put off the gold miners.
I came across this thread when it was listed around the end of last year. It's definitely an interesting piece and I've found almost no other information about it. I thought it'd be a nice project to restore and document it - even put in an offer, but I guess it was below your limit ;-)