Purpose: DBLSPACE is a disk compression utility that is included
with
DOS, beginning with Version 6. It provides a way to increase disk
capacity by
compressing the data on all or part of a disk.
Discussion
To start the full-screen interface of the DBLSPACE disk-compression
program you
enter
dblspace
by itself on the command line. Then, you control each individual aspect
of the
DBLSPACE program by entering options and parameters at the DOS command
line.
The sections that follow describe each of the DBLSPACE options that are
available.
NOTE:
Some versions of DOS 6 may not include the DBLSPACE program. In
addition, it
has been reported that the use of the DBLSPACE program that was first
included
in DOS Version 6 can result in data storage errors, especially when
DBLSPACE is
used in combination with the SMARTDrive program. However, it has also
been
reported that these problems were fixed in the 6.2 version of DOS. Some
versions of DOS may include other methods of compressing stored data.
Option 1. DBLSPACE / AUTOMOUNT
Syntax:
DBLSPACE / automount=drive
Enables or disables automatic mounting of removable drives. The default
is for
automatic mounting of removable drives. You cannot use this command
while
Windows is running.
Option
drives - Specifies the removable drives that you want DBLSPACE to
automatically mount.
Option 2. DBLSPACE / CHKDSK
Syntax:
DBLSPACE /chkdsk [/F] [d:]
Tells DBLSPACE to check the structure of a compressed drive and report
any
errors found. Using the /F option will cause DBLSPACE to attempt to fix
found
errors. (This option is not available with DOS 6.2. You should use the
SCANDISK utility instead.)
Option
/F - Tells DBLSPACE to repair any errors that it finds.
Option 3. DBLSPACE / COMPRESS
Syntax:
DBLSPACE /compress d: [/newdrive=host:]
[/reserve=size] [/F]
Used to compress the files on an existing hard disk, floppy disk, or
other removable disk.
Options
/newdrive=host - Specifies the uncompressed host drive after
compression. If
not specified, the next available drive letter will be used. (You can
abbreviate newdrive as new.)
/reserve=size - Specifies the amount of space to be left uncompressed
on the
host drive. The default for hard disks is 2M and for floppy disks,
0.
/F - Causes DBLSPACE to return to the DOS command prompt when
compression is
finished rather than displaying compression statistics.
Creates a new compressed drive by using free space on an uncompressed
drive.
This option can only be used on nonremovable drives.
Options
/newdrive=host - The new compressed drive. The default is the next
available letter.
/reserve=size - Specifies the amount of space to be left uncompressed
on the
host drive. If you omit both the /reserve and size options , 1M of
uncompressed
space will be reserved on your disk. You cannot use the /SIZE and
/RESERVE
options at the same time.
/size=size - Specifies the size of the compressed volume file that will
be
created on the host drive. You cannot use the /SIZE and /RESERVE options
at the same time.
Option 5. DBLSPACE / DEFRAGMENT
Syntax:
DBLSPACE /defragment [d:] ]/F]
Used to defragment a compressed drive. This is accomplished by moving
all of
the drive`s free space to the end of the drive. To stop the
defragmenting process, press the Esc key.
Option
/F - Tells DBLSPACE to defragment the drive more completely.
Option 6. DBLSPACE / DELETE
Syntax:
DBLSPACE /delete d:
Used to unmount a compressed drive and delete its compressed volume file
from
the host drive. To delete all the files on a compressed drive, it is
better to
use the DBLSPACE/FORMAT option.
Option 7. DBLSPACE / DOUBLEGUARD
Syntax:
DBLSPACE /doubleguard=0|1
The Doubleguard option monitors the integrity of the memory being used by
DBLSPACE to minimize memory corruption. Restart your computer after
using the
Doubleguard option.
Option
0|1 0 disables DoubleGuard and 1 enables it.
Option 8. DBLSPACE / FORMAT
Syntax:
DBLSPACE /format d:
Used to delete all files and subdirectories on a compressed drive,
leaving the
drive intact.
Option 9. DBLSPACE / INFO
Syntax:
DBLSPACE [/info] [d:]
Used to display information about a specified compressed drive including,
it`s
host drive, used and free space, actual and estimated compression ratio,
and the
total size.
Option
/info - If you do use this option without specifying a drive the
current drive
will be assumed.
Option 10. DBLSPACE / LIST
Syntax:
DBLSPACE /list
Used to display information about all the compressed and uncompressed
local
drives connected to your computer. The letter, type, free space, total
size and
CVF files name are displayed for each drive. Information will not be
displayed
for networks and CD-ROM drives.
Option 11. DBLSPACE / MOUNT
Syntax:
DBLSPACE /mount[=nnn] host: [/newdrive=d:]
Tells DBLSPACE to associate a drive letter with a compressed volume file
(CVF) so that files in the CVF can be accessed as if they were on a disk.
Options
=nnn - Used to mount the CVF named DBLSPACE.nnn on the host drive. The
default is DBLSPACE.000.
host: Specifies the uncompressed host drive that contains the CVF you
want to access.
/newdrive=d: - Used if you are mounting a CVF file created with
the /COMPRESS option (nnn=000). d: is the drive letter you want to use
for the host drive after the CVF is mounted. When mounting a CVF
created with the /CREATE option (nnn>000), d: is the drive letter you
want to use for the compressed drive after the CVF file is mounted.
Option 12. DBLSPACE / RATIO
Syntax:
DBLSPACE /ratio[=ratio] [d:] [/all]
Determines the estimated compression ratio that DBLSPACE
will use when compressing a drive.
Options
=ratio - Specifies the new estimated compression ratio
(from 1.0 to 16.0). This number must be entered with one decimal place.
/all - Used to change the estimated compression ratios for all mounted compressed drives.
Option 13. DBLSPACE / SIZE
Syntax:
DBLSPACE /size[=size] [/reserve=size] d:
Used to change the size of a compressed drive.
Options
=size - Specifies the space that the CVF on the specified drive
should take up on its uncompressed host drive.
/reserve=size - Specifies the amount of free space to be left on the
uncompressed host drive are the specified drive is resized. You cannot
use both =size and /RESERVE=size at the same time.
d: - Specifies the compressed drive for which you want to change the
size.
Option 14. DBLSPACE / UNCOMPRESS
Syntax:
DBLSPACE /uncompress d:
Used to uncompress a drive previously compressed with DBLSPACE. Once you
have
removed all compressed drives, DBLSPACE will be removed from memory.
Option 15. DBLSPACE / UNMOUNT
Syntax:
DBLSPACE /unmount [d:]
Used to break the association between a drive letter and a compressed
volume file (CVF). This will make the compressed drive temporarily
unavailable.
For more information about this command, refer to the downloadable book DOS the Easy Way.
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