From: lehmann at ans-netz.de
Hi,
dwight elvey wrote:
I removed the original drive and put in a ST251
that has a similar
sector/head to what I needed for the M20.
That might work here as well but I probably would still need some kind of
adapter board because even the SA1000 harddisk is not attached directly
to the controller but to a so called "FINCH adapter board" which itself
is connected to the controller. Unfortunally I have no idea how that
adapter board looks like nor do I have the schematics.
How is the memory mapped in the S8000? The
Olivetti has one 64K map
that Data and the instruction map to two different physical
memory locations. This seems to be required for the implementation
of CPM-8000 that I have running on the M20.
The system comes with 1MB DRAM and it uses 3 MMUs. all three are used in
the non-segmented operation mode of the Z8001 as code, data and stack
MMU (one 64K segment only). In the segmented operation mode, two MMUs are
used to access 128 possible memory segments of 64K.
Hi
I think that should work. As I recall, the BIOS operations all
switched to the non-segmented mode in specific segements as
required. When actually running CP/M-8000, it was running
in the segemented mode ( as I recall ). An application might
run in either mode.
To load instructions, it mapped both instruction and data into
the same physical space and then switched to another segement
of the processor to run the 128K mapped space.
The assembler that came with the M20 always assumed you were in
the segemented mode and didn't even have the option of non-segemented.
The assembler in CP/M-8000 allowed both modes so I'm not sure
how it was expected to be managed.
Dwight
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