Notes:

The PUBlic patch for CP/M 2.2 was released some years ago by 
PluPerfect Systems for non-commercial distribution. I have always 
found Bridger Mitchell's implementation of PUBlic to be far superior 
to the Echelon/ZRDOS method. Echelon sets entire user areas to be 
'public', while Bridger's method treats PUBlic as a file attribute. 
Over time, many reports of spurious behavior have surfaced regarding 
the user-area method, and I personally missed the flexibility of 
PUBlic being determined on a file-by-file basis. Since PUBlic was 
incompatible with ZRDOS, I gave it up with some reluctance when 
updating my o/s.

Recently, while poking around in ZRDOS17 with a disassembler, I 
realized that large portions of it's internals are suspiciously 
similar to BDOS. It was not difficult to locate the code 
corresponding to DRI's SEARCHN routine, the area affected by the 
PUBlic patch. After some head-scratching, I developed the file 
PUBPTZ10.Z80, which overlays ZRDOS and enables use of f2 as the 
PUBlic attribute. Obviously the original user-area method will no 
longer operate. BackGrounder ii is sensitive to certain sections of 
absolute code in ZRDOS/BDOS, but does not seem to complain about the 
modifications; accepting it as 'PUBLIC ZRDOS'.

Installation instructions may be found in the beginning of the 
PUBPTZ10.Z80 file. They should be reasonably clear to anyone advanced 
enough to be attempting this sort of hack.

I must include the usual "don't scream at me if it eats your files" 
clause:

ANY MODIFICATIONS OF THIS NATURE HAVE THE POTENTIAL TO RAISE HAVOC, I 
**DON'T**  CLAIM TO HAVE TESTED THIS UNDER ALL POSSIBLE CIRCUMSTANCES 
- SO BE CAREFUL, AND DON'T TEST IT ON YOUR HARD-DISK UNTIL YOU ARE 
SURE IT WORKS!!

Note also that the internal offsets will almost certainly not be 
correct for earlier or later versions of ZRDOS. They may also be 
incorrect for the pre-release version of ZRDOS17 which many sysops 
and good-neighbor helpers were asked to evaluate.

I have included the entire contents of PluPerfect's PUBPATCH.LBR for 
the sake of completeness. Please leave any comments and/or bug 
reports, brickbats, threats, etc. on Z-Node Central, Lilliput (System 
#1), or Jay Sage's board. 

Steven Hirsch

8/29/87