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DBLSPACE (DRVSPACE)

Description | Syntax | Parameters | Switches | Related | Notes | Examples | Errorlevels | Availability

Compresses hard disk drives or floppy disks, and configures drives that were compressed by using DoubleSpace, the integrated compression that was included with MS-DOS 6 and MS-DOS 6.2.

Syntax

Note: The switches and parameters for the DBLSPACE command are identical to those of the DRVSPACE command, just type DRVSPACE instead of DBLSPACE when issuing the command.

Start DoubleSpace/DriveSpace program that provides an easy-to-use, menu-oriented user interface for creating and managing DoubleSpace/DriveSpace compressed drives:
DBLSPACE

DBLSPACE /AUTOMOUNT=char

DBLSPACE /COM[PRESS] drive: [/NEW[DRIVE]=drive2:] [/RES[ERVE]=size] [/F]

DBLSPACE /CR[EATE] drive: [/N[EWDRIVE]=drive2:] [/RE[SERVE]=size | /SI[ZE]=size]

DBLSPACE /DEF[RAGMENT] [/F] [drive:]

DBLSPACE /DEL[ETE] drive:

DBLSPACE /DOUBLEGUARD=char

DBLSPACE /F[ORMAT] drive:

DBLSPACE drive: /HOST=drive2:

DBLSPACE [/INFO | drive:]

DBLSPACE /LASTDRIVE=drive:

DBLSPACE /LI[ST]

DBLSPACE /MAXFILEFRAGMENTS=n

DBLSPACE /MAXREMOVABLEDRIVES=n

DBLSPACE /MO[UNT]=nnn drive: [/NEW[DRIVE]=drive2:]

DBLSPACE /RA[TIO][=n.n] [drive: | /ALL]

DBLSPACE /ROMSERVER=n

DBLSPACE /SI[ZE][=size] | /RES[ERVE]=size] drive:

DBLSPACE /SWITCHES=char

DBLSPACE /UNCOMPRESS drive:

DBLSPACE /UNMOUNT [drive:]

Parameters
drive: (v6.0)
Specifies the drive you want to defragment. If omitted, DoubleSpace defragments the current drive.
DoubleSpace will not allow you to delete/format drive C.
Switches
/ALL (v6.0)
Specifies that you want to change the ratio of all currently mounted compressed drives.
/AUTOMOUNT=char (v6.0)
Modifes the AUTOMOUNT setting in the DBLSPACE.INI file. The AUTOMOUNT setting enables or disables the automatic mounting of removable drives, including floppy disk drives. By default, DoubleSpace automatically mounts all removable drives.
Note: For this switch to take effect, you must restart your computer.
The values for /AUTOMOUNT=char are:
/COM[PRESS] (v6.0)
Compresses the files on an existing hard disk drive, floppy disk, or other removable media. Compressing an existing drive (drive:) makes more space available on that drive.
Note: DoubleSpace cannot compress a drive that's completely full. To compress your startup hard disk drive, the drive must contain at least 1.2 MB of free space. Other hard disk drives and floppy disks must contain at least 1.1 MB of free space. (DoubleSpace cannot compress 360K floppy disks.)
You can use DoubleSpace to increase the storage capacity of floppy disks in addition to hard disks. After compressing a floppy disk, you can use it to store data or to transfer data from one computer to another.
Compressing a floppy disk is similar to compressing an existing hard disk drive. You can compress a floppy disk that is completely empty or one that contains a few files. (Make sure the floppy disk is formatted and has at least 1.1 MB of free space. DoubleSpace cannot compress a floppy disk that is full. DoubleSpace also cannot compress 360K floppy disks.)
In general, you use a compressed floppy disk just as you would a normal floppy disk. The main difference is that, to use a compressed floppy disk to transfer data from one computer to another, both computers must be running DoubleSpace.
By default, DoubleSpace automatically mounts a compressed floppy disk when you try to use that disk. However, if you disable DoubleSpace's Automount feature in order to save memory, you must mount each compressed floppy disk yourself, before you can use it.
If you have turned off Automount, when you first compress a floppy disk, DoubleSpace mounts it for you. However, if you change floppy disks or restart your computer, you will have to remount the floppy disk before you can use it again.
To mount a floppy disk, use the /MOUNT option.
To enable or disable DoubleSpace's Automount feature, use the /AUTOMOUNT option.
/CR[EATE] (v6.0)
Creates a new compressed drive (drive:) by using free space on an existing uncompressed drive. The new compressed drive will provide more storage capacity than the amount of space it uses.
/DEF[RAGMENT] (v6.0)
Defragments the selected compressed drive. Defragmenting a compressed drive consolidates the free space on it. If you are planning to reduce the size of a compressed drive, you should first use the Defragment command to consolidate the drive's free space. You can then make the drive smaller than you could if you did not first defragment it.
The DEFRAG command optimizes disk performance by reorganizing the files on a drive. You can use DEFRAG to optimize uncompressed drives. Although you can run DEFRAG on a compressed drive, doing so will probably not improve your system's speed.
Unlike the DEFRAG command, the /DEFRAGMENT switch does not speed up your system. /DEFRAGMENT simply consolidates a compressed drive's free space so that all the free space is at the end of the compressed volume file. This provides the fullest utilization of your disk space, and also enables you to reduce the size of the compressed drive more than you otherwise could.
To defragment a compressed drive as much as possible, use both the DEFRAG command and the /DEFRAGMENT switch:
  1. Defragment the drive by using the DEFRAG command.
  2. Defragment it again by using the DBLSPACE /DEFRAGMENT /F command.
  3. Defragment it a third time by using the DBLSPACE /DEFRAGMENT command without the /F switch.
/DEL[ETE] (v6.0)
Deletes the selected compressed drive (drive:) and erases the associated compressed volume file.
CAUTION: Deleting a compressed drive erases the entire drive and all the files it contains.
If you accidentally delete a compressed drive, you might be able to restore it by using Microsoft Undelete. When DoubleSpace deletes a compressed drive, it actually deletes a file on your uncompressed drive. This file is called the "compressed volume file". A compressed volume file has a filename in the form DBLSPACE.nnn (ie. DBLSPACE.000).
First, restore the deleted compressed volume file by using Undelete. Once you have restored the file, remount it by using the DBLSPACE /MOUNT command. If DoubleSpace cannot remount the compressed volume file, run ScanDisk on that compressed volume file.
/DOUBLEGUARD=0|1 (v6.0)
Modifes the DOUBLEGUARD setting in the DBLSPACE.INI file. The DOUBLEGUARD setting enables or disables DoubleGuard(tm) safety checking. When DoubleGuard is enabled, DoubleSpace will constantly check its memory for damage by some other program. If it detects any memory damage, DoubleSpace will halt your computer to minimize damage to your data. By default, DoubleGuard is enabled.
Note: For this switch to take effect, you must restart your computer.
The values for /DOUBLEGUARD=char are:
/F (v6.0)
Prevents DoubleSpace from displaying the final screen when compression is complete. This screen includes compression statistics. If you specify the /F switch, DoubleSpace returns to the command prompt when compression is complete.
Enables the specified drive to be defragmented more fully.
/F[ORMAT] (v6.0)
Formats the selected compressed drive.
CAUTION: Formatting a compressed drive deletes all the files it contains. You cannot unformat a drive that has been formatted by using /FORMAT.
/HOST=drive: (v6.0)
Changes the drive letter of the host drive for the specfied compressed drive by modifying the corresponding ActivateDrive setting in the DBLSPACE.INI file. You cannot use this switch to change the letter of a compressed drive's host drive if you used free space to create that compressed drive.
Note: For this switch to take effect, you must restart your computer.
/INFO (v6.0)
Displays information about the selected drive's (drive:) free and used space, the name of its compressed volume file, and its actual and estimated compression ratios.
/LASTDRIVE=drive: (v6.0)
Modifes the LASTDRIVE setting in the DBLSPACE.INI file. The LASTDRIVE setting specifies the highest drive letter available to DoubleSpace. (If another program uses one of the drive letters specified for DoubleSpace, the highest drive letter available to DoubleSpace will be higher than that specified by LASTDRIVE.)
Note: For this switch to take effect, you must restart your computer.
/LI[ST] (v6.0)
Lists and briefly describes all your computer's compressed and uncompressed drives (except network drives and CD-ROM drives), and specfies whether DoubleSpace's Automount and DoubleGuard features are enabled or disabled.
/MAXFILEFRAGMENTS=n (v6.0)
Modifies the MAXFILEFRAGMENTS setting in the DBLSPACE.INI file. The MAXFILEFRAGMENTS setting sets the limit for the amount of fragmentation allowed for all mounted compressed volume files.
Note: For this switch to take effect, you must restart your computer.
The maximum number of fragments (n) in which the compressed volume files may be stored on the host drive. For each fragment, 6 bytes of memory are allocated.
/MAXREMOVABLEDRIVES=n (v6.0)
Modifes the MAXREMOVABLEDRIVES setting in the DBLSPACE.INI file. The MAXREMOVABLEDRIVES setting specifies how many additional drives DoubleSpace should allocate memory for when your computer starts. This determines how many additional compressed drives you can create, compress, or mount without restarting your computer.
Note: For this switch to take effect, you must restart your computer.
The number of additional drives (n) for which DoubleSpace should allocate memory when your computer starts. DoubleSpace allocates 96 bytes of memory for each additional drive.
/MO[UNT]=nnn (v6.0)
Establishes a connection between a compressed volume file (CVF) and a drive letter so that you can use the files the CVF contains. DoubleSpace usually mounts CVFs automatically. You need to mount a CVF only if you previously unmounted it, or if the CVF is located on a floppy disk and Automount is disabled.
Directs DoubleSpace to mount the compressed volume file with the filename extension specified by the nnn parameter. If nnn omitted, DoubleSpace attempts to mount the compressed volume file named DBLSPACE.000.
/N[EWDRIVE]=drive2: (v6.0)
/NEW[DRIVE]=drive2: (v6.0)
Specifies the drive letter for the uncompressed (host) drive. After DoubleSpace creates/compresses an existing drive, your system will include both the existing drive (now created/compressed) and a new uncompressed drive. if omitted, DoubleSpace assigns the next available drive letter to the new drive.
Specifies the drive letter to assign to the new mount drive. If omitted, DoubleSpace assigns the new drive the next available drive letter.
/RA[TIO][=n.n] (v6.0)
Changes the estimated compression ratio of the selected drive. DoubleSpace uses this ratio to estimate how much free space the drive contains. You might want to change the estimated compression ratio if you plan to store new files with a compression ratio that differs greatly from the current ratio.
To change the ratio to a specific number, specify the ratio you want. You can specify a ratio from 1.0 to 16.0. If you don't specify a ratio, DoubleSpace sets the drive's estimated compression ratio to the average actual compression ratio for all the files currently on the drive.
/RE[SERVE]=size (v6.0)
/RES[ERVE]=size (v6.0)
Specifies how many megabytes of free space to leave uncompressed. To make the compressed drive as large as possible, specify a size of 0. Because some files, such as the Windows swap file, do not work properly when stored on a compressed drive, it's a good idea to reserve some uncompressed space. The uncompressed space will be located on the new uncompressed drive. (If the drive you are compressing contains a Windows permanent swap file, DoubleSpace moves the file to the new uncompressed drive.)
If omitted, DoubleSpace reserves 2 MB of free space.
/ROMSERVER=n (v6.0)
Modifes the ROMSERVER setting in the DBLSPACE.INI file. The ROMSERVER setting enables or disables the check for a ROM BIOS Microsoft Real-time Compresson Interface (MRCI) server. By default, the ROM MRCI check is disabled.
CAUTION: Do not enable the MRCI check unless you are certain that you have hardware that uses the MRCI. The MRCI check can interfere with a ROM BIOS that does not have the MRCI.
Note: For this switch to take effect, you must restart your computer.
The values for /ROMSERVER=n are:
/SI[ZE][=size] (v6.0)
Specifies the total size, in megabytes, of the compressed volume file. (This is the amount of space on the uncompressed/host drive that you want to allocate to the compressed drive.)
Enlarges or reduces the size of a compressed drive. You might want to enlarge a compressed drive if its host drive contains plenty of free space. You might want to reduce the size of a compressed drive if you need more free space on the host drive.
If you omit BOTH /SIZE and /RESERVE switches, DoubleSpace makes the drive as small as possible.
/SWITCHES=char (v6.0)
Modifes the SWITCHES setting in the DBLSPACE.INI file. The SWITCHES setting controls the way the CTRL+F5 and CTRL+F8 keys work. (Used to bypass DoubleSpace when your computer starts.)
If your DBLSPACE.INI file does not contain a /SWITCHES setting, you can use CTRL+F5 or CTRL+F8 to keep from loading DoubleSpace when your computer starts.
Note: For this switch to take effect, you must restart your computer.
To remove any /SWITCHES settings in your DBLSPACE.INI file, you must edit the file directly.
The values for /SWITCHES char are:
[/]F
Reduces the amount of time you have to press CTRL+F8 or CTRL+F5 when your computer starts. Use this setting to speed up processing of your startup files. (Although you do not use the "/" character when specifying the F parameter, the setting in the DBLSPACE.INI file is SWITCHES=/F.)
[/]N
Prevents you from using CTRL+F8 or CTRL+F5 to bypass DoubleSpace when your computer starts. (Although you do not use the "/" character when specifying the N parameter, the setting in the DBLSPACE.INI file is SWITCHES=/N.)
If you choose this setting and press CTRL+F8, the operating system will still allow you to selectively choose commands in your CONFIG.SYS and AUTOEXEC.BAT files. If you choose this setting and press CTRL+F5, the operating system will still bypass your AUTOEXEC.BAT and CONFIG.SYS files.
/UNCOMPRESS (v6.0)
Uncompresses a drive (drive:) that was compressed by using DoubleSpace. When you uncompress the last mounted drive, the /UNCOMPRESS switch also removes DBLSPACE.BIN from memory. (DBLSPACE.BIN is the portion that provides access to compressed drives. It uses about 50K of memory.)
Before uncompressing your drive, you should back up the files it contains. To back up your files, use Microsoft Backup for MS-DOS or Microsoft Backup for Windows.
When you uncompress a drive, DoubleSpace either changes that drive's letter or the letter of its host drive (depending on how the compressed drive was originally created.) DoubleSpace shows how the drive letters will change when it uncompresses the drive.
Some programs have settings that include explicit pathnames and drive letters. If a program's settings specify a drive that is no longer valid after uncompressing, the program will probably display an error message or be unable to find one of its components or data files. In that case, you need to correct the drive letter specified by that setting.
You can uncompress a drive only if the data it contains will fit on the host drive. If you use the DBLSPACE /UNCOMPRESS command, and DoubleSpace indicates your drive will not have enough free disk space, delete unnecessary files or move them to another drive.
If the root directories of the compressed and host drives contain files or directories with identical names, DoubleSpace cannot uncompress the compressed drive. If this happens, DoubleSpace displays an error message, and creates a DBLSPACE.LOG file that lists the files involved. Use the TYPE command to view the contents of the DBLSPACE.LOG file. Then, remove or rename one copy of each file, and then try uncompressing the drive again.
When you uncompress the last mounted compressed drive, DoubleSpace first uncompresses the drive, and then removes DBLSPACE.BIN from memory. (DBLSPACE.BIN is the portion of the operating system that provides access to compressed drives. It uses about 50K of memory.) If there are any unmounted compressed drives left on your computer, you will not be able to mount them until you reinstall DoubleSpace. (To reinstall DoubleSpace, type DBLSPACE at the command prompt.)
/UNMOUNT (v6.0)
Breaks the connection between the selected drive's compressed volume file and its drive letter. Unmounting a drive makes it temporarily unavailable.
You cannot unmount drive C.
Related

SWITCHES

Notes
What does DoubleSpace do?

DoubleSpace is a disk-compression program. It stores more files in less space by storing those files more efficiently. Most files are stored fairly inefficiently -- somewhat like a sponge that has a lot of air holes in it. When you squeeze a sponge, it becomes temporarily smaller; but when you let go of it, the sponge returns to its original shape and size. When you compress a drive, DoubleSpace "squeezes" the files on that drive until they are as small as possible -- just like squeezing a sponge. A file stored on a compressed drive stays "squeezed" until you use it. When the file is loaded into memory, DoubleSpace uncompresses the file so that it returns to its original size, just as a sponge does when you let go of it. When you're finished using the file, DoubleSpace "squeezes" it again and stores it back on the compressed drive.

When should I use DoubleSpace?

You should use DoubleSpace if you are running low on disk space and don't want to invest in a larger hard disk drive. DoubleSpace can dramatically increase your available disk space. However, because DoubleSpace uses at least 33K of memory, it makes sense not to install DoubleSpace unless you need it.

How does DoubleSpace "squeeze" a file?

Most files contain a lot of repeated data. When DoubleSpace finds repeated data in a file, it retains the first occurrence of that data, and replaces any other occurrences of that data with a cross-reference to the first occurrence. The cross-reference takes less space than the original data.

Why does DoubleSpace compress some files more than others?

Some files contain more repeated data than others. (Program files are usually compiled so that they are stored as efficiently as possible; program files are typically not as compressible as some other types of files. Bitmap files and text files typically compress well, since most such files contain a lot of repeated data. Files that were already compressed by using a standalone compression program (ARJ, RAR, ZIP) usually do not compress any further; although you can store such files on a compressed drive, there is little advantage to doing so.

Will DoubleSpace slow down my system?

If you have a computer with a fast CPU and a fast hard disk, you probably won't notice much difference in system speed after installing DoubleSpace. If you have a fast CPU and a slow hard disk, DoubleSpace might actually improve your system's speed. If your computer has a slow CPU, you may notice a reduction in speed after compressing your drive.

What happens during DoubleSpace Setup?

DoubleSpace Setup configures your computer to run DoubleSpace and compresses the drive of your choice. DoubleSpace Setup first runs ScanDisk to check your hard disk for logical and physical errors. If necessary, it runs the Microsoft Defragmenter to defragment the files on your disk. Finally, it compresses the files on your drive. For more information about running DoubleSpace Setup, see "Freeing Space by Using DoubleSpace" in the MS-DOS User's Guide or the MS-DOS User's Guide Addendum.

Now that I've installed DoubleSpace, why do I have an additional drive?

When DoubleSpace Setup is complete, you will have an additional drive.

If you chose to create a new compressed drive, the additional drive is the compressed drive you just created.

If you compressed an existing drive the additional drive is an uncompressed drive. It is used to store files that must remain uncompressed (such as the Windows swap file). The additional drive also contains important system files such as:

CAUTION: Do not delete or otherwise tamper with the hidden files on the new drive. If you do, you might lose your compressed drive and all the files it contains.

For more information about DoubleSpace Setup, see the "Understanding Disk Compression" section of "Freeing Space by Using DoubleSpace" in the MS-DOS User's Guide or the MS-DOS User's Guide Addendum,

Can I copy a file from a compressed drive to an uncompressed drive?

Yes. You can copy files between compressed drives and uncompressed drives just as you would between two uncompressed drives. A file is actually compressed only when it is stored on a compressed drive. When you copy a file from your compressed drive, DoubleSpace reads the file into memory and uncompresses it. The file is then copied to the uncompressed drive in its uncompressed state.

Do I need to recompress the drive after add more (uncompressed) files to it?

No. Whenever you copy a file to a DoubleSpace drive, DoubleSpace saves the file in compressed form. It doesn't matter whether the file was on the drive when you compressed the drive.

If I'm using DoubleSpace, what should I do to maintain my system?

In general, maintaining a computer that's running DoubleSpace is just like maintaining an uncompressed system. To ensure the safety of your data and the stability of your system, do the following frequently (ie. once a week):

How should I back up my files if I'm using DoubleSpace?

You should back up and restore the files on a compressed drive just as you would the files on an uncompressed drive. (For information about using Microsoft Backup, see the chapter "Managing Your System" in the MS-DOS User's Guide.)

When backing up the files on the host drive (the uncompressed drive that contains the compressed volume file (CVF) for your compressed drive), you typically do not need to back up any files that have names in the form DBLSPACE.nnn (ie. DBLSPACE.000). The DBLSPACE.nnn file essentially contains your compressed drive. Although it is possible to back up the DBLSPACE.nnn file, doing so is redundant if you have also backed up the files on that compressed drive. In general, it's best to back up the files on your compressed drive directly, rather than by backing up the associated CVF (the DBLSPACE.nnn file). This is because backing up only the CVF does not allow you to restore individual files or directories later. When you restore the backup copy of a DBLSPACE.nnn file, it replaces the entire compressed drive with the backup copy. This means that you will lose all changes to all files on that drive that were made since the backup copy was created.

I installed DoubleSpace and now I'm running out of memory. What can I do?

If you have an 80386 or higher computer, run MemMaker after installing DoubleSpace. MemMaker can move portions of DoubleSpace out of conventional memory, which makes more memory available for running programs. Also, make sure the BUFFERS command in your CONFIG.SYS file is set to no more than 10 buffers.

If you have an 80286 or higher computer with at least 1 MB of memory, make sure your CONFIG.SYS file contains a DOS=HIGH command, a DEVICE command for HIMEM.SYS and a DEVICE command for DBLSPACE.SYS. (MS-DOS Setup and DoubleSpace Setup normally add these commands to your CONFIG.SYS file.) With these commands, the operating system and parts of DoubleSpace can load into the high memory area.

Is it all right to run SMARTDrive if I'm using DoubleSpace?

SMARTDrive and DoubleSpace are designed to work together. If Setup determines that your computer has enough memory to run SMARTDrive, it automatically installs SMARTDrive by adding a SMARTDRV command to your AUTOEXEC.BAT file. In particular, you should run SMARTDrive if you are running DoubleSpace and you use Windows; in that case, using SMARTDrive can significantly speed up your computer.

SMARTDrive is designed to speed up your system and safeguard your data. By default, Setup configures SMARTDrive so that write-caching is disabled. (If SMARTDrive was originally configured to allow write-caching, Setup will not change your configuration.) Write-caching provides much faster performance than read-only caching, but is not as conservative.

DriveSpace and DoubleSpace

Note: MS-DOS 6.22 does not include DoubleSpace compression. Instead, MS-DOS 6.22 includes DriveSpace compression, which appears similar to DoubleSpace but which stores compressed information in a different format.

If you currently use DoubleSpace, you can continue to do so with MS-DOS 6.22.

If you currently use DoubleSpace and want to use DriveSpace instead, you can convert your system to DriveSpace. See Converting from DoubleSpace to DriveSpace.

If you do not currently use DoubleSpace and want to compress your drives, use DriveSpace. To do this, type DRVSPACE at the command prompt. See "Freeing Disk Space by Using DriveSpace" in your Microsoft MS-DOS User's Guide or Microsoft MS-DOS User's Guide Addendum.

Creating a startup floppy disk

To create a startup floppy disk if you are running DoubleSpace, use either the SYS command or the FORMAT /S command. Each of these commands creates a floppy disk that should in most cases be able to start your computer. However, to make sure, you should also copy the DBLSPACE.BIN file from the directory that contains your files to the root directory of the startup floppy disk.

Loading DBLSPACE.BIN into the HMA

If you are running DoubleSpace and you upgraded to MS-DOS 6.22 from MS-DOS 6.2, you can load a portion of DBLSPACE.BIN into the High Memory Area (HMA). You must have an 80286 or higher computer with at least 1 MB of memory and your CONFIG.SYS file must contain a DOS=HIGH command, a DEVICE command for HIMEM.SYS, and a DEVICE command for DBLSPACE.SYS. (MS-DOS Setup and DoubleSpace Setup normally add these commands to your CONFIG.SYS file.)

If you upgraded from MS-DOS 6.0, DBLSPACE.BIN cannot be loaded into the HMA; in this case, you can save about 14K of memory by converting to DriveSpace, which can load into the HMA.

Converting from DoubleSpace to DriveSpace

If you are running DoubleSpace, you can convert your DoubleSpace drives to DriveSpace format. (If you purchased the U.S. version of the MS-DOS 6.22 Upgrade, you can obtain conversion by sending in the enclosed coupon; if you purchased the MS-DOS 6.22 Step-Up or non-U.S. version of MS-DOS 6.22, your version of MS-DOS 6.22 already includes conversion.)

Note: Before converting, it's a good idea to back up the data on each DoubleSpace drive.

To convert your DoubleSpace drives, type DBLSPACE at the command prompt. DriveSpace starts. To convert your drives, follow the instructions on your screen. DriveSpace converts all mounted DoubleSpace drives to DriveSpace format, and also converts your system to run DriveSpace instead of DoubleSpace.

Note: The conversion process can take a long time, especially if your DoubleSpace drives contain a lot of data. You might want to plan to carry out the conversion process overnight.

For more information about converting to DriveSpace, see the README.TXT file.

Keeping DoubleSpace files after conversion

After conversion, do not delete any of your DoubleSpace program files, especially the DBLSPACE.BIN file and the DBLSPACE.MR1 file. These files are required in the following situations:

Using DoubleSpace drives and floppy disks with DriveSpace

DriveSpace converts only DoubleSpace drives that were currently mounted during the conversion process. As a result, after the conversion is complete, you might still have some unconverted DoubleSpace floppy disks or other unmounted DoubleSpace volume files. DriveSpace can still mount unconverted DoubleSpace drives for read-only access; this means that you can read but not change the information stored on that drive.

DriveSpace does not automatically mount DoubleSpace floppy disks; to mount an unconverted DoubleSpace floppy disk, you must mount it yourself by using the DBLSPACE /MOUNT command or by running DriveSpace and choosing the Mount command from the Drive menu.

For DriveSpace to mount any DoubleSpace drive for full (read/write) access, you must first convert the drive to DriveSpace format. Run DriveSpace, and then choose Convert DoubleSpace from the Tools menu.

Fixing problems with drives compressed using DriveSpace

To repair disk problems, use the ScanDisk program, a full-featured disk analysis and repair utility. ScanDisk can check and repair both compressed and uncompressed drives. It can even check and repair unmounted DoubleSpace compressed volume files.

Running the DBLSPACE command without switches or parameters

The first time you run the DBLSPACE command, it starts the DoubleSpace Setup program. DoubleSpace Setup compresses your hard disk drive and loads DBLSPACE.BIN into memory. DBLSPACE.BIN is the part of the operating system that provides access to compressed drives.

Thereafter, when you run the DBLSPACE command without specifying any switches or parameters, the DoubleSpace program starts. This program lists your compressed drives and provides menu commands for working with them. You can perform all DoubleSpace tasks either from within the DoubleSpace program or from the command line.

DBLSPACE.BIN and DBLSPACE.SYS

DBLSPACE.BIN is the part of what provides access to your compressed drives. When you start your computer, the operating system loads DBLSPACE.BIN along with other operating system functions, before carrying out the commands in your CONFIG.SYS and AUTOEXEC.BAT files. DBLSPACE.BIN initially loads in conventional memory, since it loads before device drivers that provide access to upper memory. Normally, if your hard drive has been compressed using DoubleSpace, DBLSPACE.BIN is loaded even if you press F5 or F8. For information about starting your computer without loading DBLSPACE.BIN, see Starting your computer without loading DBLSPACE.BIN.

The DBLSPACE.SYS device driver does not provide access to compressed drives; it simply determines the final location of DBLSPACE.BIN in memory. When loaded with a DEVICE command, the DBLSPACE.SYS device driver moves DBLSPACE.BIN from the top to the bottom of conventional memory. When loaded with a DEVICEHIGH command, DBLSPACE.SYS moves DBLSPACE.BIN from conventional to upper memory, if available. Whenever possible, DBLSPACE.SYS moves a portion of DBLSPACE.BIN into the HMA.

Starting your computer without loading DBLSPACE.BIN

DBLSPACE.BIN is the part of the operating system that provides access to DoubleSpace compressed drives. Normally, if your hard drive has been compressed using DoubleSpace, DBLSPACE.BIN is loaded even if you press F5 or F8. There are two ways to disable this:

  1. To start your computer without loading DBLSPACE.BIN, and to bypass all the commands in your CONFIG.SYS and AUTOEXEC.BAT files, press CTRL+F5.
  2. To start your computer without loading DBLSPACE.BIN, and to bypass individual commands in your CONFIG.SYS and AUTOEXEC.BAT files, press CTRL+F8. The operating system will then prompt you to carry out or bypass each CONFIG.SYS and AUTOEXEC.BAT command. To carry out all remaining startup commands, press ESC. To bypass all remaining startup commands, press F5.
Note: If you bypass DBLSPACE.BIN, you will not be able to gain access to your DoubleSpace compressed drives until you restart your computer with DBLSPACE.BIN. (Your compressed drives will remain on your hard disk as hidden files with names such as DBLSPACE.000. Do not delete or rename such files.)
How DoubleSpace assigns drive letters

When you install DoubleSpace, it creates a new drive and assigns a drive letter to that drive. DoubleSpace skips the first four available drive letters and assigns the next available drive letter to the new drive. These four drive letters are assigned to additional drives.

When assigning letters to additional drives (when you compress another drive), DoubleSpace works backwards from the first drive letter it assigned.

DoubleSpace attempts to avoid drive-letter conflicts with drives created by FDISK, RAMDrive, networks, or other installable device drivers that assign drive letters. However, if a drive-letter conflict does occur, DoubleSpace resolves the conflict by reassigning its drive letters.

Compressing a RAMDrive

To compress a RAMDrive, use the DBLSPACE /CREATE command. Although it is possible to compress a RAMDrive by using the DBLSPACE /COMPRESS command, it is not recommended. Due to the inherent volatility of a RAMDrive, DoubleSpace's automatic recovery mechanisms cannot work on a RAMDrive.

If you compress your RAMDrive, make sure the DEVICE command for RAMDRIVE.SYS appears in your CONFIG.SYS file before the DEVICE=DBLSPACE.SYS command. Otherwise, the compressed RAMDrive will not be automatically mounted when your computer starts.

DBLSPACE.INI File

The DBLSPACE.INI file is a text file with the System, Read-Only, and Hidden attributes. DoubleSpace stores this file in the root directory of your startup drive. The DBLSPACE.INI file contains variables that DoubleSpace uses when your computer starts.

Note: Although it is possible to change these variables yourself (by using the DBLSPACE command or by editing the file directly), you should do so only if you understand what they do and what the results might be. Before changing the DBLSPACE.INI file, you should make a backup copy of the file. For changes to the DBLSPACE.INI settings to take effect, you must restart your computer.

The DBLSPACE.INI file can contain one or more of the following variables:

Examples

If you have floppy drives A and B, and a Bernoulli removable drive D, to enable automatic mounting of all these drives: 

    DBLSPACE /AUTOMOUNT=1

Note: Before a floppy drive actually mounts, you must insert the floppy disk in the drive, and then begin using the floppy disk.

If you just want to enable automatic mounting of floppy drives A and B, use: 

    DBLSPACE /AUTOMOUNT=AB

To uncompress drive E, type: 

    DBLSPACE /UNCOMPRESS e:

To compress drive D: 

    DBLSPACE /COMPRESS d:

Because this command does not specify how much space to leave uncompressed, DoubleSpace leaves 2 MB of uncompressed space (the default). Because the command does not specify a drive letter for the uncompressed drive, DoubleSpace assigns the next available drive letter to the new uncompressed drive (the host drive).

To direct DoubleSpace to compress drive E, assign the drive letter F to the new uncompressed drive (the host drive), and leave 4 MB of uncompressed space on drive F: 

    DBLSPACE /COMPRESS e: /NEWDRIVE=F: /RESERVE=4

To create a new compressed drive that uses all available space on uncompressed drive E: 

    DBLSPACE /CR e: /RE=0

To create a new compressed drive by using 10 MB of space on uncompressed drive E: 

    DBLSPACE /CREATE e: /SI=10

To create a new compressed drive by using space on uncompressed drive D, and to direct DoubleSpace to leave 2.75 MB of free space on drive D: 

    DBLSPACE /CREATE d: /RESERVE=2.75

To create a new compressed drive by using all but 2 MB of the space on drive D: 

    DBLSPACE /CREATE d:

Because the command includes neither the /RESERVE nor /SIZE switches, DoubleSpace uses the default value for the /RESERVE switch and leaves 2 MB of space on drive D.

To defragment compressed drive D: 

    DBLSPACE /DEFRAGMENT d:

To defragment the current compressed drive: 

    DBLSPACE /DEFRAGMENT

To defragment compressed drive C as much as possible: 

    DEFRAG c:
    DBLSPACE /DEFRAGMENT /F c:
    DBLSPACE /DEFRAGMENT c:

Direct DoubleSpace to delete compressed drive E: 

    DBLSPACE /DELETE e:

DoubleSpace then deletes the compressed volume file for drive E. This completely erases drive E and all the files it contains.

Direct DoubleSpace to format compressed drive E: 

    DBLSPACE /FORMAT e:

DoubleSpace then formats compressed drive E, which completely erases all the files on it.

Display information about the current drive: 

    DBLSPACE /INFO

Display information about drive C: 

    DBLSPACE /INFO c:

Display information about drive E: 

    DBLSPACE e:

Display a list of your computer's drives (except network drives and CD-ROM drives): 

    DBLSPACE /LIST

DoubleSpace displays information similar to: 

Drive  Type                        Total Free  Total Size  CVF Filename
  A    Removable-media drive       No disk in drive
  B    Compressed floppy disk         1.27 MB     1.27 MB  H:DBLSPACE.000
  C    Compressed hard drive         13.99 MB    96.49 MB  K:DBLSPACE.000
  D    Local hard drive               2.38 MB    39.98 MB
  E    Local hard drive              37.33 MB   201.94 MB
  F    Available for DoubleSpace
  G    Available for DoubleSpace
  H    Floppy drive                   0.00 MB     0.70 MB
  I    Available for DoubleSpace
  J    Available for DoubleSpace
  K    Local hard drive              12.52 MB    66.80 MB

DoubleGuard safety checking is enabled.
Automounting is enabled.

To mount a compressed floppy disk in drive A: 

    DBLSPACE /MOUNT a:

To mount the compressed volume file DBLSPACE.001 located on uncompressed drive D: 

    DBLSPACE /MOUNT=001 d:

To change the estimated compression ratio of all your compressed drives to match each drive's actual compression ratio: 

    DBLSPACE /RATIO /ALL

To change drive D's estimated compression ratio so that it is 3.2 to 1: 

    DBLSPACE /RATIO=3.2 d:

To change the estimated compression ratio of the current drive to 6 to 1: 

    DBLSPACE /RATIO=6

To have DoubleSpace adjust the compression ratio for all your drives each time your computer starts, add to the end of your AUTOEXEC.BAT file: 

    DBLSPACE /RATIO /ALL

To change the size of drive C so that its compressed volume file uses 60.5 MB of space on drive D: 

    DBLSPACE /SIZE=60.5 c:

To change the size of drive E so that its host drive, drive D, contains 20 MB of free uncompressed space: 

    DBLSPACE /SIZE /RESERVE=20 e:

To change the size of drive C so that it is as large as possible: 

    DBLSPACE /SIZE /RESERVE=0 c:

To uncompress drive E: 

    DBLSPACE /UNCOMPRESS e:

To unmount drive E: 

    DBLSPACE /UNMOUNT e:

If your compressed drive letter is C, and your host drive letter is H, you can change the host drive letter to G: 

    DBLSPACE c: /HOST=g:
You can also change the host drive letter to G: 
    DBLSPACE h: /HOST=g:
Errorlevels

none.

Availability
External
DOS
v6.0 v6.2 v6.21 v6.22
Windows
none
Windows NT
none
Last Updated: 2003/07/28
Direct corrections or suggestions to: Rick Lively