25 Dec
2010
25 Dec
'10
12:05 p.m.
pair of 6303
microprocessors). But the 5.25" floppy drive appears to run
CP/M (or something close) on its intenral processor. The 3.5 drive, BTW,
doesn't...
Ah HUH?
Speaking for the PX-8 (I have three plus wedges and drives) the base PX8
runs CP/M with a menu program on boot. If you escape from the menu it's stock CP/M. ti's clever for it's time in that
the BIOS is complex and
complete
enough to handle a raft of storage devices be they based on R0M, RAM or
a real floppy. As it turns out they made the floppy smart so that some of
Not forgettign the microcassette tape,. which is trated somewhat like a
slow floppy drive by the system.
bios is in the floppy and the system can do directed
calls to it so the main
unit is relieved of some of the work.
So the Floppy for the PX8 is specialized for a CP/M host it's not running
CP/M itself as there is not enough ram alone to qualify.
Have you ever looked inside the TF20 daul 5.25" floppy unit? I beleive
schematics are on the web somewhere...
There is a heck of a lot of elkectronics inside. One large PCB containg a
Z80, 2K (IIRC) boot ROM ()with logic to switch it out after booting), 64K
DRAM, floppy controller, a duaghterboard with a 7201 serial chip, etc.
From what others have been saying that's easily
enough to run CP/M. Note,
I am not talking about the CP/.M that runs in the PX8 or
wherever. I am
talking about the Z80 in the TF20 itself.
And the TF20 is not specialised for a CP/M host. The original application
was for the HX20, which as I said has a poair of 6303 CPUs and does not
run CP/M.
-tony