SPEEDING UP DISK RESETS
               WITH TURBOROM AND P*PS ENHANCEMENTS

5/28/86

Purpose:

The CP/M operating system disk reset function cause the allocation
table for drive A and the currently logged in drive to be rebuilt.
For a large hard disk with many blocks this can take a substantial
amount of time making the system appear very sluggish during warm boots.
The patch on this disk allows this shortcoming of CP/M to be removed for
those who have both the Advent TurboROM and Plu*Perfect Systems operating
system enhancements (CP/M 2.2e).

Operation:

The Advent TurboROM reserves the high bit of the first byte of the
extended DPH as a flag which specifies whether the allocation table of
this drive requires rebuilding.  The ROM initializes this so that all
drives require rebuilding.  Only those drives with a zero length checksum
vector are assumed to have non-removable media and only these are
candidates for avoiding the rebuilding of the allocation table.  Drive A
is a special case as it must still be scanned for the occurence of
'$$$.SUB'.  This process is still considerably faster than actually
rebuilding the vector.  Any program which plays tricks with the
allocation map should ALWAYS reset the high bit of the extended DPH so
that the allocation will be forced to rebuild.  Plu*Perfect Systems
utilities such as PUTDS (version 1.2 and later) and PUTBG (to be
released) always do this.  If you are unfamiliar with the extended
DPH, please refer to the notes available on the TurboROM developers
support disk.

The patches to the CP/M BDOS are internal, but require the space available
in the P*PS enhancements.  For other users of the TurboROM the source code
to the patch is included, but Plu*Perfect Systems cannot support and attempts
to modify this code.  Please do not ask us.

Installation:

A general purpose utility program MERGEPRL is included which will take any
CDL format REL file and merge it with a Digital Research format PRL file to
produce another PRL file.

Usage is

MERGEPRL   infile  outfile

and then you will be prompted for the patch file name.  The input and output
file names can be the same and so not need the PRL suffix.  If you use the
same input and output names, make sure that you have a backup.

The PRL file you will use should be TURBOSYS.PRL or TURBO-DS.PRL and
when prompted for the patch REL file you should type in SKIPMAP.
The output file name will require renaming to TURBOSYS.PRL or TURBO-DS.PRL
for relocation wiht MOVTURBO.