25 Dec
2010
25 Dec
'10
11:35 a.m.
On 12/25/2010 01:11 PM, Tony Duell wrote:
The PX-8 is a CP/M system based on Rom and Ram disk with
hooks for external extension for both greater rom/ram disk or
the floppy device. Sure, as is the PX4 (I have both). The HX20, of course is not
(it uses a
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
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.
Allison
Or on the
Epson RC20!
The Epson TF20 (floppy drive for the HX20, PX4, PX8, etc) contains a
Z80
and 64K RAM. Oh, and a boot ROM that is mapped out after booting. I have
never analyhsed the system disk in detail, but I have a feeling this
thing runs CP/M internally.
-tony