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- PCMANAGE and DCOMPRES Documentation file
-
- UTILITIES
- Vol. 8, No. 21
-
- Ross M. Greenberg
- December 12, 1989 (Utilities)
-
- Purpose: To provide automatic compression of infrequently accessed files and
- automatic decompression when they are called. The user can set the
- inactive period necessary before a file is compressed, can restrict
- the drive and/or path of operation, and can specifically exclude
- named files or directories.
-
- Format: DCOMPRES [/i] [/An]
-
- Remarks: DCOMPRES is a memory-resident program that should be loaded from an
- AUTOEXEC.BAT file. In each subdirectory it creates and maintains a
- file called INDEX.CMP. This file stores the date and time each file
- was last accessed and whether the file is compressed or not. When a
- compressed file is called, DCOMPRES decompresses it automatically.
-
- INDEX.CMP files are normally created with a Read-Only file attribute,
- as they should never be deleted while any compressed files remain in
- the directory. To remove a directory requires changing this file
- attribute with the DOS ATTRIB command (for DOS 3.x) or with a utility
- such as ATTR.COM (PC Magazine, June 10, 1986). INDEX.CMP files can be
- created with other attributes by loading DCOMPRES with its optional
- /An switch, where n has one of the following values: 0 (visible,
- read-write); 1 (hidden, read-write); 2 (visible, read-only--the
- default); or 3 (hidden, read-only).
-
- If an INDEX.CMP file is accidentally deleted or damaged, all compressed
- files in a directory can be restored by loading DCOMPRES with its
- optional /i switch parameter and issuing a command such as COPY *.*
- NUL.
-
- Format: PCMANAGE [/i] [/dn] [/cn] [/bn] [/pd]
-
- Remarks: When invoked with its default settings, PCMANAGE compresses all files
- on drive C: (including those in all subdirectories) that have not been
- accessed in 7 days and whose compression will save at least 10 percent
- in file length and 2,048 bytes (nominally one cluster). The user can
- change the number of days before compression by employing the optional
- /dn switch with values from 1 to 32767 for n. Similarly, the optional
- /cn switch sets the minimum acceptable compression percentage and
- accepts any n value of 5 or greater. The /bn switch sets the number
- of bytes in one disk cluster (the minimum real saving possible); it
- accepts values from 1024 to 32767 for n.
-
- The optional /pd switch, with an appropriate drive letter (and/or path)
- entered for d, allows PCMANAGE to be used on drives other than C: and
- permits restricting its operations to the files along a specific path
- (and its subdirectories).
-
- The /i switch is used with PCMANAGE when installing the utility. This
- should not be done until after you have prepared any necessary
- DCOMPRES.EXL (exclude) file, as described in the Notes below. That
- done, and with DCOMPRES loaded, use the DOS DATE command to set the
- current date back by at least one week. Then enter PCMANAGE /i, which
- will cause it to examine all files on drive C: (or as modified by the
- /pn switch). Use the DATE command to reset the present date and run
- PCMANAGE again, without the /i parameter. All files on the drive
- except those excluded by DCOMPRES.EXL or the optional /pn switch will
- now be compressed initially, if warranted by the disk space savings.
- The files will be decompressed as soon as accessed, and programs called
- frequently will not be compressed again.
-
- Running PCMANAGE weekly will automatically cause files that have become
- stale-dated to be compressed.
-
- Note 1: Up to 100 files or directories (and child directories below them) can
- be excluded from possible compression by PCMANAGE. All OS/2 files and
- copy-protected software should be so excluded. To do so, create a
- pure ASCII file called DCOMPRES.EXL in the root directory of drive C:.
- List one entry per line. To exclude all files that have a .SYS
- extension and all files in and under an OS2 directory on drive C:, the
- DCOMPRES.EXL file would have two entries:
-
- *.SYS
- C:\OS2\*
-
- Note 2: DCOMPRES and PCMANAGE can handle a maximum of 100 files per directory.
- Files in excess of this number will not be harmed, but will not be
- processed.
-
- Note 3: DCOMPRES should be installed in the AUTOEXEC.BAT file before any
- anti-virus software. Anti-virus software that uses checksumming
- procedures that cannot be disabled until program execution time is
- incompatible with DCOMPRES.
-
-