31 Dec
2011
31 Dec
'11
9:24 p.m.
On 12/31/2011 12:15 PM, MikeS wrote:
----- Reply:
Just curious:
Does your memory configuration support swapping out the RDOS
boot/monitor ROM?
Not at the moment, I haven't quite worked out if this can be made to
work properly with non-Cromemco memory boards. The 64FDC manual
suggests "Set[ting] the switches on the RAM board(s) so that memory from
8000h to FFFFh is disabled..." which implies that the boards must
support some way of re-enabling the memory via software (for when the
FDC's ROM is disabled via a write to port 40h).
I'm wondering if this board isn't really optimal for this setup -- it
seems very geared toward having a complete Cromemco setup, which I do
not have.
I do have an IMSAI MIO and a Tarbell 1011D, which seem more
period-appropriate for the era. The MIO has got to be the most
difficult to configure board I have ever seen. I've modified wire-wrap
backplanes with less hassle than this thing. There must be 50 or more
(poorly labeled) jumpers on this board and the manual is not the most
friendly I've ever seen (it doesn't help that the PDF I have has the
pages in the wrong order). (Anyone out there have experience with this
board? I don't really care much about getting the Cassette I/O or
parallel I/O working, I just want a serial port for the time being...)
I just need to spend more time studying the manual, I'm sure :).
And what drive(s) do you have connected? As you
probably know, the FDC
supports 5.25"DD as well as 8" and the 3.5 and 5.25" HD equivalents.
None at the moment, but I'm planning on connecting a 5.25" drive in the
near future.
I haven't seen any standalone BASIC versions for the FDC; there are at
least two versions of BASIC for the Cromemco, but AFAIK they both
require a bootable CDOS disk. However, unless they use any of the
extra calls in CDOS I wouldn't be surprised if they worked just as
well with CP/M.
For right now, I was just planning on assembling a raw binary image and
using a PC (with a bit of hacked together software) to push the image
into the IMSAI's memory via the 64FDC's serial port, using the onboard
monitor commands. Just for fun :).
In addition to Cromemco's CDOS CP/M equivalent AFAIK there were also
at least two official third-party CP/M implementations for the FDC and
one or two hacked BIOSes, but there may be compatibility issues among
the three different versions of the FDC.
If you know of a source for images of these third-party CP/Ms, let me
know. Dave Dunfield's site has a CP/M for the 16FDC, which as far as I
can tell (from a cursory glance at the manuals) has identical I/O port
behavior to the 64FDC so I may just be able to use that, assuming I can
write the 8" image to a 5.25" floppy.
Interesting though; I'll have to look around...
Thanks!
Josh