Date   : Tue, 08 Dec 1987 12:23:30 PST
From   : Bridger Mitchell <bridger%rcc@rand-unix.ARPA>
Subject: Re: running DU on a CPM3 system

DU  uses direct bios file i/o to access disk sectors.  It's an
example of a program that needs repackaging to run under cp/m 3.
To use it, get CPM2RSX (or similarly-named RSX) and use the
CP/M 3 utility to encapsulate a COM file with that RSX.

That particular RSX converts  cp/m 2.2-style direct bios io calls
to cp/m 3 calls via the dos AND provides full physical->logical
sector deblocking.

However, as noted previously, you can't just put a zcpr3 cp/m 2.2 type
command processor on the boot tracks of a cp/m 3 system and
go; it requires rebuilding the interface from the ground up.