> Date: Sat, 10 May 2008 12:29:24 -0400
> From: Dave McGuire
> I dunno Chuck...the only reason more CP/M systems
weren't ROM-
> resident back in the day was due to convention, not
technical
> restrictions. I (personally) don't think there's
anything
> non-"period" about ROM-ing CP/M.
It's not the ROM-ing of CP/M that disturbs me, but rather
the
"disklessness" of the thing. Wasn't the whole
idea of CP/M
originally to give you something to manage files on your
floppy
drives? I mean, that's what the bulk of the code in CP/M is
for--
heaven knows, the support for other I/O is nothing to write
home
about.
If one wants to enjoy a "vintage" experience, what
sense is there in
being diskless? At any rate, even something as simple as a
WD1770-
type controller added to the design would give that
capability with a
minimum of support "glue".
Alternatively, one could stay diskless and add a
sound-effects module
to emulate the "chunk" and "grrr" of a
head-load and seek--and the
"thunk-click" of a drive door being opened and a
floppy inserted.
I still don't have the hang of this "vintage"
thing yet, probably
because I'm vintage myself. Please forgive my density...
Cheers,
Chuck
-----REPLY-----
Hi Chuck,
I hear what you are saying and agree there is something just
very
disconcerting about diskless CP/M computers. However, CP/M
in the CBIOS is
really just about block devices and the OS really could care
less whether
you attach a 8" SSSD floppy, a CF drive or a ROM. It
is all the same to the
BDOS.
My goal here is to *eventually* allow expansion to include
IDE and floppy
drives. As a matter of fact, the CBIOS does support IDE
hard disks already
but requires the interface IO card and the ECB backplane to
attach it to the
SBC. I have an IDE hard disk with CP/M format and some
programs on it.
My goal with the SBC using ROM/RAM drives was to allow
something minimal to
operate as a SBC and have some functionality with the option
to expand to as
desired. I am trying for a modular, low cost approach with
easy to build
increments.
Assuming I get this SBC respun and into manufacturing my
next project is to
redo my ECB backplane as a PCB. After that will be the disk
IO board and
bus debuggers which are also made from prototype boards.
My Test Prototype home brew computer was built entirely with
prototype
boards and point to point wiring. It supported IDE drives
and even had a
NEC765 FDC circuit built in. I wrote some software but
never got around to
test the FDC part since the machine started experiencing
reliability
problems which I think trace back to poor grounding and
power distribution
issues. The new PCB SBC version seems much more solid than
the prototype
did.
The SBC is something which works but gives only limited
functionality. If
that is enough, people can stop there. If they want more
they can plug it
into the ECB backplane and add peripheral cards. So far
only two peripheral
cards exist; the disk IO card and the bus debugger.
Hopefully more in the
future. I have some ideas kicking around in my head but am
concentrating on
the SBC for now.
Thanks and have a nice weekend!
Andrew Lynch
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