You understand correctly Steve.
Map 2 is the same as Map 1 except that it brings in 1KB of Remem at a
time which looks like a disk Track to CP/M. I know where my disk
read/write routines are and I know where the 1KB block appears, so it's
quite safe.
I've tailored the BIOS to suit Remem in this case. CP/M works with
128-byte sectors, so I have 8 sectors per track and 256 tracks per disk,
giving 256KB disks. However it's common to block & de-block sectors in
the BIOS to suit any hardware requirement.
Philip
On 9/07/2017 2:54 PM, Stephen Adolph wrote:
Thanks Philip.
So if I understand
. Lower 32k space has either m100 Rom or ram.
. Upper 32k space has a single ram block.
I guess you access the disks using the fine grained ram access? 1kb
at a time?
On Saturday, July 8, 2017, Philip Avery <pav...@xtra.co.nz
<mailto:pav...@xtra.co.nz>> wrote:
Thanks Steve
Yes, bank switching to std ROM for interrupts. Also means ROM
calls from Basic, C or any language can easily be made as long as
it's finally despatched from himem (above 8000H).
A memory map should answer your queries:
0 - 7FFFH M100 ROM
8000H - FFFFH CPM RAM (0-32KB)
10000H - 17FFFH CPM RAM (32KB - 64KB)
18000H - 57FFFH Disk A
58000H - 97FFFH Disk B
Philip
On 9/07/2017 11:53 AM, Stephen Adolph wrote:
Wow! Phil you've been busy!
I'll have to think about what you're doing with the memory banks.
I assume you are also in all ram mode? Are you bank switching to
std Rom?
In terms of hardware... not easy to map to rex. Rex2 maybe.
But one could imagine a hybrid that uses the rex technique for
writing to a read only socket to enable at least 3 banks of ram.
On Saturday, July 8, 2017, Philip Avery <pav...@xtra.co.nz
<javascript:_e(%7B%7D,'cvml','pav...@xtra.co.nz');>> wrote:
Well, it's arrived as far as Virtual T. It will need a new
hardware device developed to use on a real M100.
Over a decade in the making (started in 2006), I present 64K
CP/M 2.2 running in VT with Remem enabled. The Remem is used
as RAMdisk, to emulate two disk drives of about 241KB each.
To share this with the group, it would be easiest to share my
VT remem.bin (6MB). Together with my instructions in pdf,
you'll be on the air very quickly.
John Hogerhuis: May I send this to you to host on the
bitchin.com <http://bitchin.com> site?
Ken Pettit: Will my windows variant of remem.bin work with
all the other variants of VT 1.7?
While in theory it will work on a real M100 with Remem, and
with additional software could use a NADSBox to talk to the
modern world (SD card) - I think as these two items aren't
readily available, it would best if a new hardware solution
is developed. Now that it's working in the M100 environment,
it's relatively straightforward to modify the BIOS to work
with any RAMdisk, other storage device or even a wireless
solution.
Thanks to Mike Stein for some beta testing.
Philip
