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List:       classiccmp
Subject:    Re: Introduction
From:       Roger Holmes <roger.holmes () microspot ! co ! uk>
Date:       2008-05-30 20:09:13
Message-ID: A281DE58-EE13-4ABD-B1CA-8FE6707B5795 () microspot ! co ! uk
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On 30 May, 2008, at 18:00, cctalk-request@classiccmp.org wrote:

>
> Message: 9
> Date: Fri, 30 May 2008 17:11:02 +0200
> From: Oliver Lehmann <lehmann@ans-netz.de>
> Subject: Introduction
> To: Classic Computers Mailing List <cctalk@classiccmp.org>

Welcome Oliver.


> The system runs a Z8001 with 3 MMUs and Z80-peripherial ICs (PIO,  
> SIO...)
> It also has 2 SIOs for 4 terminal connections, and one PIO to  
> connect the
> WDC. The system also has two furhter PIO chips to establish a  
> connection
> to the 8Bit system. The system runs with up to 4MB of DRAM but it  
> might
> run with more RAM with self-made RAM modules.


Three MMUs seems a bit weird. I last programmed a Z8001 in 1979 so  
maybe things have changed between then and when your machine was  
built. If I remember correctly, the Z8010 MMU mapped 64 of the 128  
segments, you could have one MMU and address 64 chunks of up to 64k  
in the 16MB address range. With two MMUs you could access all 128  
chunks. Are the MMUs set up for different processes, or are they  
divided into instruction and data accesses or some other way?

The system I worked on would have eventually had 12 Z8001s each with  
one MMU and 128K of local RAM plus the CPU were grouped into modules  
of three and had about 3MB of RAM in the module and each module could  
also access the other 3 module's RAM, but with more wait states. Each  
Z8001 was responsible for managing a wide microprogrammed bit slice  
processor for doing heavy mathematics, though the details might still  
be secret even though the project was cancelled in the mid eighties,  
several years after I left the company.

I got involved quite early, the first draft of the Z8001 instruction  
set manual which I was given included a memory to memory transfer  
instruction, but that was dropped before they issued the first sample  
chips about a year later. A bit of a blow as we had started writing a  
Coral 66 compiler for it by then.

When I retire I might get around to getting myself a Z8001 system if  
there's any still around by then. I am kept busy at work programming  
Apple Macs and at home restoring a 1962 mainframe computer (ICT 1301)  
and restoring/maintaining my old cars (2 Daimlers, 2 Rovers, a Land  
Rover, a Jaguar and a BMW).

I think you would have to be lucky to get your C code to use exactly  
the same registers as the original object code. Are you sure it was  
originally C or could it have been assembly code?


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