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LBRDISK2.NQT
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LBRDISK2.NOT
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Text File
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1991-01-30
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2KB
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42 lines
Implementing LBRDISK with ZCPR2
ZCPR2 checks the drive code when attempting to log into a
new disk. Since LBRDISK is often used to create psuedo drives
higher than the installed drive, it is necessary to change the
MAXDISK equate in ZCPRHDR.LIB. Besides, it is the responsibility
of the BIOS to check for (and gracefully recover from) an invalid
physical disk selection.
I suggest setting MAXDISK to 15 and re-installing ZCPR2.
Oh, and it is a good idea to set MAXUSER to 15 for compatibility
with CP/M+ and other CP/M systems.
If you have the source code for your BIOS the beginning of
the SELDSK routine should be something like the following:
SELDSK: MOV A,C ;Get new disk
LXI H,0 ;Flag possible invalid disk
CPI MAXDSK ;or whatever the variable name for
;maximum physical drive is.
JC DSKOK ;Jump if ok
XRA A
STA 4 ;So that the CCP is not caught in
;a loop
RET
DSKOK: STA SEKDSK ;or whatever the variable name is
.
.
(Remainder of SELDSK routine)
.
.
If there is room in your BIOS, you should install code to
print an error message on select error, and jump to WBOOTE.
Note: it must jump to WBOOTE, not to WBOOT so that the RSX
manager can intercept.
Jim Lopushinsky
March 7/84
403-484-5981 @ 300/1200 baud.