Date   : Sat, 12 Jan 1985 05:36:34 GMT
From   : jason%jett.uucp@BRL-TGR.ARPA
Subject: Re: cp/m+ incompatibility

CPM+ incompatibilities...
  I am a happy owner of Osborne Executive owner... but...
Osborne did a bad thing... they goofed with the index registers in the bios
before saving them on the stack... something that is not sopposed to happen,
as some software packages (TURBO pascal for one i think) use the IX and IY
index registers without saving them before a BDOS call. ZAP! The new 1.21
rom availiable from osborne is supposed to fix this problem. When I get
this Rom, if anyone is interested I will research it. I do know that the
RSX i wrote works well for this purpose. Osbornes have given cpm+ a bad
name for no reason... IT IS 100% COMPATIBLE with 2.2, but some programs
such as public domain BYE does not work since the BDOS and BIOS are actually
stored in other pages of ram, so it makes it difficult to patch them.
An RSX is a Resident System Extension... cpm thinks of it as a routine
to run before entering bios. This is a legal patch that cpm accounts for.
The one I wrote just saves IX and IY on the stack, goes through to BDOS,
then when returning, pops them back off the stack...
Correct me if I am wrong please.... 
    Jason Hamby        ihnp4!akgua!jett!jason