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PACK.HLP
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Text File
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1988-02-29
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6KB
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159 lines
; v 1.0
PACK -- Disk Packing Utility
I Introduction
U Usage
M Messages
:I
Introduction
PACK reorganises CP/M disks to improve file access times. It requires
ZCPR3 with CP/M 2.2 or ZRDOS, and a Z80 or compatible processor. It
will only run if the user has wheel priviledge.
The data on a given disk is rearranged in situ so that all the data
associated with each file is contiguous. This reduces disk head
movement when that file is subsequently read or modified. The user can
specify certain files which should not be moved, and can specify
priorities among the remaining files, so that the most frequently
accessed files are moved close to the disk directory for reduced access
time.
:U
Using PACK
Follow these steps -
1. Make a list of fixed and priority files
2. Backup the disk
3. Sort the directory
4. Run PACK
The file list
PACK requires an input file which specifies which files on the disk must
remain where they are and which of the remaining files should be moved
to the beginning of the disk. The structure of this file is a sequence
of file names and file classes, one to a line. File classes (fixed or
mobile) are specified by a line beginning with a semi-colon. So a
typical file list might be:
; Fixed
*:!!*.*
*:BADSECT*.*
; Mobile
CMD:COMMAND.LBR
ROOT:*.*
This means that all files in any user area matching !!*.* and BADSECT*.*
remain fixed (on my system these are PluPerfect DateStamper and
Backgrounder files, and files which lock out flakey sectors). Then the
library file containing less frequently used COM files is moved to the
front, followed by all files in my ROOT directory. PACK automatically
appends *:*.* to the end of the mobile list, so all remaining files on
the disk follow on.
Case is not significant in the file list, and blank lines are ignored.
Directories can be given in DU: or DIR: form. * or ? in the directory
field means all user numbers. If a disk is specified implicitly or
explictly it must correspond to the disk specified on the command line
(see D option below).
Backing up the disk
You should do this reqularly, and always before running PACK. Not that
a disk crash is more probable while running PACK than at other times,
but it is more certainly catastrophic if it does happen. You will
definitely have to restore the disk from your backup copy (floppies or
tape) if the system crashes due to a power failure or inadvertent reset
while PACK is running.
Sorting the directory
Use CLEANDIR or SAP to sort the directory entries on the disk. The file
list given to PACK preempts directory order, but within each group of
files which match an entry in the file list directory order determines
the order in which the data is packed.
Running PACK
Enter the command: PACK <flist> <options>
<flist> is required and is the name of the file containing the list of
fixed and mobile file patterns. The possible options are:
Dx - pack disk x (default is the disk on which flist resides)
S - display statistics only. No packing takes place.
V - be verbose. The file patterns extracted from <flist> are
displayed, and then the group permutation table (mainly
for debugging).
Examples:
B>PACK FLIST.C DCS - display number of allocation groups that
would have to be read and written to
pack disk C according to the file list
FLIST.C
B>PACK FLIST.C DC - as before, but 'for real'
PACK will ask for confirmation before proceeding to pack the disk. The
process takes anywhere from a few seconds to maybe half an hour
depending on how much data must be moved and how fast your disk hardware
is. If you get impatient, on no account switch off or reset the
machine. If you hit ^C the program will attempt to cut short the
packing process, but it may take some time to reach a convenient
consistent state.
:M
Messages
Normal messages:
Ready to pack disk x
Are you sure you wish to proceed? (y/n) -
Disk packed
Statistics report:
nnnn group reads and mmmm group writes required to pack disk.
Interrupt:
PACK: interrupted by user - you pressed ^C
Problems with options:
Option not recognized: x
No such disk: x
Disk specification missing
Problems with <flist>
Line xxxx: invalid filename
Line xxxx specifies disk x (y expected)
Line xxxx: can't interpret directory specification
Line xxxx too long: truncated.
Disk read/write errors:
Can't read directory - disk read error
read error at group gggg:ss - group cannot be read/written,
write error at group gggg:ss - see PACK.DOC for recovery
General problems:
PACK requires CP/M 2.2 (or ZRDOS)
Can't find <flist>
Disk x is set read only
Out of memory - you have a tiny TPA
Disk overflow (can't happen!) - more groups are allocated in
the directory than there are
groups on the disk