Date : Mon, 24 Jul 1989 20:25:12 GMT
From : uci-ics!zardoz!tgate!ka3ovk!drilex!axiom!linus!nixbur!nixpbe!ugun13!josef@cs.ucla.edu
Subject: ramdisk under cpm
george@flight.UUCP writes:
> /* ---------- "ramdisk under cpm" ---------- */
>
> Is there such a thing as a Ram disk driver for the Apple ][ plus under
> cpm? I have an apple memory expansion card located in slot 2.
>
> When I boot up prodos this board is found to be a ramdisk called "RAM2".
>
> I currently have CPM 2.2. Would such a thing be public domain?
From my (limited) experience with CP/M I would say that You can't just
buy a "ramdisk driver".
What You need to do is to change Your machine's BIOS to allow the entries
HOME, SELDSK, SETTRK, SETSEC, READ and WRITE
to recognize Your RAMdisk.
Depending on the (current) implementation, it would probably be
sufficient to modify HOME, READ and WRITE, as the other ones merely
update some memory locations with the desired values which are later
used by READ and WRITE (with respect to HOME, my CP/M Operating System
Manual says "The disk head of the currently selected disk (...) is
moved to the track 00 position", although You can "translate into a
call to SETTRK with a parameter of 0" which in turn "...seek the
selected track at this time or delay the seek until the next READ or
WRITE actually occurs").
You could probably call the RAMdisk disk E: (A:-D: being used for floppies).
Josef Moellers
paper mail: e-mail:
c/o Nixdorf Computer AG USA: uunet!linus!nixbur!mollers.pad
Abt. DX-SC 1 !USA: mcvax!unido!nixpbe!mollers.pad
Heinz-Nixdorf-Ring Phone:
D-4790 Paderborn (+49) 5251 104691
+-----------------------------------------------------------------------+
| "Many that live deserve death. And some that die deserve life. |
| Can You give it to them? Then do not be too eager to deal out |
| death in judgement" |
| Gandalf to Frodo in "The Fellowship of the Ring"|
+-----------------------------------------------------------------------+