Date   : Thu, 08 Jan 1987 12:33:53 EST (Thursday)
From   : Marty <Leisner.Henr@xerox.ARPA>
Subject: cp/m physical directory meaning

I'm writing a program which runs on a PC and can read and write CP/M
floppy/hard disks across a SCSI interface.

I can't seem to find a good spec which describes (preferably in
pseudocode or equations) how block shift, blockmask and extent mask are
used to build/access the directory.

I can figure out easily enough how to read/write cp/m SS/SD floppies,
but playing with hard disks with large group sizes gets trickier.  DRI
documentation concerning low level disk formats seems nonexistant.

Any pointers to magazine articles, books, etc. would be useful.

A set of algorithms in C would be great.

Any help would be appreciated.
 

marty leisner
leisner.henr@xerox.com