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From: josef@ugun13.UUCP
Newsgroups: comp.os.cpm
Subject: Re: ramdisk under cpm
Message-ID: <9800007@ugun13>
Date: 24 Jul 89 20:25:12 GMT
References: <188@flight.UUCP>
Lines: 42
Nf-ID: #R:flight.UUCP:-18800:ugun13:9800007:000:1846
Nf-From: ugun13.UUCP!josef    Jul 24 08:47:00 1989



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

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