Jim Lopushinsky

                         March 22, 1984


CPM2  is a CP/M Plus system utility that allows execution of CP/M 
2.2 programs which directly access the BIOS disk system.  This is 
the first CP/M Plus utility that I wrote (about 1 year ago).  Its 
purpose  is  to allow execution of things  like  UNERA,  FINDBAD, 
NCAT,  DU,  SORTDIR, and other CP/M 2.2 utilities that would blow 
up the CP/M Plus system.

CPM2 has an attached RSX that is relocated just below the Loader.  
It intercepts all BDOS and direct BIOS calls, and performs sector 
deblocking for CP/M 2.2 programs.   BDOS function 12 returns  22, 
so  any  CP/M + programs that check the version number  will  not 
run.   In a banked system,  the RSX must load into common memory, 
so  there must be enough common memory below the BDOS base (about 
3k) to hold both the CP/M loader RSX and the CPM2 RSX.   Physical 
sectors  of up to 1k are deblocked.   On each  disk  select,  the 
allocation  vector is copied to common memory (maximum size = 512 
bytes), so that CP/M 2.2 programs that calculate disk space work.

This version requires a Z80 processor.

To delete the CPM2 RSX, use CPM2DEL.

Enjoy!!

Direct  any  comments to the SYSOP at the Meadowlark  RCPM  (403) 
484-5981 @ 300/1200 baud.