IBM Professional Series - Page 390

file, which is allocated by VM/PC during its execution, all
files on the drive where the paging file resides should be
copied; this will remove small areas of unused space that can
result in a fragmented paging file.
Using DOS Features
DOS tree-structured directories can be used for the files
needed to run
VM/PC. However, when installing VM/PC,
all the files are copied to the root directory. If you wish to
set up another
DOS directory for your VM/PC files, you will
need to copy (using the
DOS COpy command) the VM/PC
files to the desired directory. After doing so, you can erase
the
VM/PC files from the root directory if you wish.
Both
VM/PC and DOS provide facilities for printing files
while executing other tasks. When
VM/PC is running, it
attempts to control the printer for its own printer spooling
functions.
For this reason, the DOS PRINT command queue
should
be empty prior to invoking VM/PC.
Certain DOS commands can be used to configure your
system.
One of these, the BUFFERS command, is used to
set the number of buffers
DOS is to reserve at startup time.
The number chosen can
significantly affect the performance
of programs running under
VM/PC. To find the value best
for you, we suggest you measure the performance of your
most frequently used
VM/PC applications with the number
of buffers set
to several different choices. While there is no
one number
that is best for all programs, a choice of between
10 and
15 buffers is recommended as a starting point.
FORMAT Command Performance
The performance of the CMS FORMAT command can be
improved by the use of the
NOERASE option. Normally, the
FORMAT command will clear all of the blocks of the
minidisk
to zeros. When formatting a CMS minidisk with the
NOERASE option, the blocks are not cleared, and the
performance
of the command is improved. The NOERASE
option should not be used if previous data on the minidisk
should
be cleared to zeros.
Appendix D. Operating Hints D-3