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# Microsoft MS-DOS 6.2 (Part 4 of 4)

Article ID: 105614

Article Last Modified on 11/21/2002

APPLIES TO

- Microsoft MS-DOS 6.2 Standard Edition

This article was previously published under Q105614

## SUMMARY

The following information was taken from the MS-DOS 6.2 README.TXT file.
NOTE: The MS-DOS 6.2 Upgrade and MS-DOS 6.2 Step-Up (both downloadable and disk versions) include the same README.TXT file.

### NOTES ON MS-DOS 6.2

### 7. DOUBLESPACE

### 7.1 Converting Your XtraDrive Disk-Compression Software to DoubleSpace

If your computer uses XtraDrive disk compression, use its uninstallation program to remove the compression, and then install DoubleSpace.

### 7.2 Converting Stacker 2.x or 3.0 Software to DoubleSpace

If your drive has been compressed using Stacker version 2.x or 3.0, you can order a utility which automatically converts data that was compressed by Stacker compression software to the DoubleSpace format. To order this utility, use the Conversion Disk Offer coupon in the back of your user's manual.
If your drive was compressed using a version of Stacker other than version 2.x or 3.0, carry out the procedure in sections 7.3 or 7.4 below.

### 7.3 Converting Stacker 3.1 Software to DoubleSpace

If your drive has been compressed using Stacker version 3.1, carry out the following procedure to remove Stacker 3.1 and install DoubleSpace.

1. Use Stacker's UNSTACK command to unstack all your Stacker drives. (If you have floppy disks compressed by using Stacker, either unstack them now or make sure they were configured using Stacker's StackerAnywhere feature.)
2. Change to the root directory of your startup hard disk drive, and then type the following commands:

   `ATTRIB -R -H -S STACKER.INI
   ATTRIB -R -H -S DBLSPACE.BIN
   DEL STACKER.INI
   DEL DBLSPACE.BIN`

3. Restart your computer.
4. Run DoubleSpace Setup by typing `DBLSPACE` at the command prompt.

### 7.4 Converting Other Disk-Compression Software to DoubleSpace

If you are not using Stacker 2.x, 3.0, or 3.1 disk compression or XtraDrive disk compression, carry out the following procedure to convert your disk-compression software to DoubleSpace.

1. Install MS-DOS 6.2 if you haven't already done so.
2. Use Microsoft Backup for MS-DOS to back up the files on your hard disk. If you didn't install Backup for MS-DOS during Setup, see the chapter "Getting Started" in the MICROSOFT MS-DOS 6 USER'S GUIDE for instructions on installing it.
3. If your Setup disks are compatible with drive A, insert Setup Disk 1 in drive A, and restart your computer. After Setup displays the first screen, quit Setup by pressing F3 twice.
   If your Setup disks are not compatible with drive A, create a startup floppy disk for drive A. To do this, insert Setup Disk 1 in drive B, and a blank floppy disk in drive A. Then type `B:SETUP /F` at the command prompt.
   When prompted, choose to install MS-DOS on the floppy disk in drive A. After Setup is finished, leave the disk in drive A, and restart your computer.
4. Use the FORMAT command to format the drive that contains the file that contains all of your compressed files. If you don't know where this file is located, see your disk-compression documentation.
   If you are reformatting drive C, include the /S switch to transfer system files to it.
5. If you formatted drive C, make sure Setup Disk 1 is in drive A or B, and type `A:SETUP` or `B:SETUP` at the command prompt.
   Follow the instructions on your screen.
6. After Setup is complete, install DoubleSpace by typing `DBLSPACE` at the command prompt. Follow the instructions on your screen.
7. Use Backup for MS-DOS to restore the files you backed up.
   NOTE When you run Microsoft Backup, you will have to configure it again. Also, you will need to retrieve the catalog file from your backup floppy disks. To do so, choose the Catalog button in the Restore dialog box.

### 7.5 DoubleSpace Setup indicates that your computer is running an incompatible disk-caching program.

If DoubleSpace Setup displays a message indicating your computer is running an incompatible disk-caching program, open your CONFIG.SYS or AUTOEXEC.BAT file, and delete the command that loads your disk-caching program. If you want to use a disk cache, add a line for the MS-DOS 6.2 SMARTDRV program in your AUTOEXEC.BAT file. For example, if your MS-DOS files are in a directory named DOS, add the following line:

`C:\DOS\SMARTDRV.EXE`

Quit your text editor, and restart your computer. Run DoubleSpace again.

### 7.6 Your compressed drive runs out of disk space.

If your compressed drive runs out of free disk space, you can use the following techniques to free some space on the drive:

1. Enlarge that drive.
2. Carry out the DBLSPACE /DEFRAG /F and DBLSPACE /DEFRAG commands on that drive.

The rest of this section explains each technique.

### Enlarging a Compressed Drive

You can enlarge a compressed drive to make more space available on it. Enlarging a compressed drive uses free space on the uncompressed (host) drive.
To enlarge the compressed drive:

1. Start the DoubleSpace program by typing `DBLSPACE` at the command prompt.
2. Select the compressed drive you want to enlarge, and then choose the Change Size command from the Drive menu.
   The Change Size dialog box appears. The New Free Space line shows how much free space the compressed and uncompressed drives will have if you choose OK.
3. Specify a smaller number for New Free Space on the uncompressed drive. Notice that as you change this number, DoubleSpace adjusts the New Free Space amount for the compressed drive. When the New Free Space amount for both drives is what you want, choose OK.
   DoubleSpace enlarges the compressed drive.

### Carrying Out the DBLSPACE /DEFRAG /F and DBLSPACE /DEFRAG Commands on your Compressed Drive

You can sometimes free additional space on a compressed drive by more fully defragmenting the drive.
NOTE You might want to carry out the following procedure overnight, since defragmenting a large or badly fragmented drive can take a long time. (To carry out the entire procedure overnight, create a batch file that contains both the commands in the procedure.)
To free space by defragmenting the drive twice:

1. Make the compressed drive the current drive.
2. Type `DEFRAG drive: /F` at the command prompt
   Where drive: is the compressed drive. For example, DEFRAG C: /F. DEFRAG will fully defragment the drive's file allocation table, then start DBLSPACE /DEFRAG to consolidate the free space in the CVF.
3. When DEFRAG finishes, type `DBLSPACE /DEFRAG /F` at the command prompt.
   DoubleSpace re-consolidates the free space on the drive so there is as much free space as possible.

### 7.7 Your uncompressed (host) drive runs out of disk space

If your uncompressed (host) drive runs out of free disk space, you can enlarge it by reducing the size of any compressed drives that are stored on that uncompressed drive. Of course, this will reduce the amount of free space on the compressed drive(s).
To enlarge the uncompressed (host) drive:

1. Start the DoubleSpace program by typing `DBLSPACE` at the command prompt.
2. Select the compressed drive whose size you want to reduce, and then choose the Change Size command from the Drive menu. (Select a compressed drive that is stored on the uncompressed drive that's out of space. To find out which compressed drives are stored on that uncompressed drive, type `DBLSPACE /LIST` at the command prompt.)
   The Change Size dialog box appears. The New Free Space line shows how much free space the compressed and uncompressed drives will have if you choose OK.
3. Specify a larger number for the New Free Space on the uncompressed drive. Notice that as you change this number, DoubleSpace adjusts the New Free Space amount for the compressed drive. When the New Free Space amount for both drives is what you want, choose OK.
   DoubleSpace reduces the size of the compressed drive, which makes more free space available on the corresponding uncompressed drive.

### 7.8 DoubleSpace did not compress all of your files because the drive ran out of disk space.

If DoubleSpace indicates that it could not compress some of your files because there was not enough disk space, carry out the following procedure.

1. To determine which drive is your uncompressed drive, type `DBLSPACE /LIST` at the command prompt.
2. Using Microsoft Backup, back up to floppy disks the files on the uncompressed drive that were not compressed.
3. Delete the files on the uncompressed drive that were not compressed.
4. Type `DBLSPACE` at the command prompt.
5. From the Drive menu, choose Change Size.
6. To increase the size of your compressed drive, decrease the size of your uncompressed drive, and choose OK.
7. From the Drive menu, choose Exit, and use Backup to restore the files you backed up to your compressed drive. If you run out of space again, repeat steps 5 through 7 until the compressed drive is large enough.

### 7.9 Windows displays the message "The permanent swap file is corrupt."

If you use a Windows permanent swap file, it must be located on an uncompressed drive. If your permanent swap file is on a compressed drive, Windows displays the message "The permanent swap file is corrupt" when it starts.
When you install DoubleSpace, the DoubleSpace Setup program checks for the existence of a Windows permanent swap file. If it finds one, DoubleSpace Setup moves the swap file to your uncompressed drive. However, if you install Windows after installing DoubleSpace, or if you use Control Panel to change the location of your permanent swap file, your swap file might end up on a compressed drive. (When you specify a drive for your permanent swap file, Windows allows you to choose a compressed drive.)
To move your permanent swap file to an uncompressed drive:

1. Start Windows.
2. At the "Permanent swap file is corrupt" screen, type `Y` in response to the question "Do you want to delete this swap file?", and then press ENTER.
3. Open Control Panel, and then double-click the 386 Enhanced icon.
4. Choose the Virtual Memory button. Windows displays a dialog box stating that a corrupt swap file was found and asks if you want to set the file's length to zero.
5. Choose the Yes button. Windows displays another Virtual Memory dialog box.
6. Choose the Change button. Windows displays swap-file settings.
7. In the Drive list box, select a drive that is not compressed. In the Type list box, select "Permanent."
   If your uncompressed drive does not have enough free space to create a permanent swap file, create a temporary swap file on either your compressed or uncompressed drives. (For information about freeing space on your uncompressed drive, see section 7.7.)
   When you have finished specifying swap-file settings, choose OK twice, and follow the instructions on your screen.

### 7.10 EXTDISK.SYS displays a warning about drive letters.

If you are using DoubleSpace on a Compaq computer, and your CONFIG.SYS file loads the EXTDISK.SYS device driver, EXTDISK.SYS displays the following message when it loads:
WARNING: EXTDISK.SYS is not the first device driver to assign drive letters. Physical hard drive letters will not be contiguous.
The EXTDISK.SYS driver still works properly. It displays this message because it expects to be the first module to assign drive letters, but because DBLSPACE.BIN loads before the CONFIG.SYS file and assigns some drive letters, EXTDISK.SYS is no longer first. (EXTDISK.SYS displays the message regardless of when the DBLSPACE.SYS device driver is loaded in the CONFIG.SYS file.)

### 7.11 You need a special device driver to use your startup drive

If your startup hard disk drive requires a device driver in your CONFIG.SYS file, do not compress that drive. If you do, your computer will not start properly, since DoubleSpace will be unable to access your startup drive. (This is because MS-DOS loads DBLSPACE.BIN, the portion of MS-DOS that accesses compressed drives, before starting any of the device drivers in your CONFIG.SYS file.)
To install DoubleSpace on a computer with a startup drive that requires a special device driver, use DoubleSpace Setup to compress a drive other than your startup drive, or use DoubleSpace Setup to create a new compressed drive using free space on any existing drive.

### 7.12 Defragmenting uncompressed drives after changing file attributes

You can safely defragment both your compressed or uncompressed drives, using the Microsoft Defragmenter or another defragmentation program, as long as you do not change the attributes of your compressed volume files.

CAUTION If you change the attributes of a compressed volume file, and then defragment that uncompressed drive without first unmounting the compressed drives, you might lose data.

If you want to fully defragment your uncompressed drive, you must first unmount all compressed drives located on the uncompressed drive, remove all their attributes, and then use DEFRAG or another defragmenter.

### 7.13 Files DoubleSpace cannot compress

Some files (such as .ZIP files) are already compressed. DoubleSpace might not be able to compress such files any further.
Encrypted data files, such as the Microsoft Mail 3.0 .MMF file, are not compressible and will be stored in uncompressed form, even if you store such files on a compressed drive.
You might want to store uncompressible files on an uncompressed drive rather than on a compressed drive. Doing so can sometimes improve your system's speed.

### 7.14 Microsoft Defragmenter runs out of memory while you are compressing a drive.

If the Defragmenter runs out of memory while you are compressing a drive, quit DoubleSpace, and then carry out the procedure in section 5.4 of this file.
If the Defragmenter still runs out of memory after you have tried these procedures, there might be too many files on your hard disk for the Defragmenter to organize. For the program to work correctly, you might need to delete some files or move them to a floppy disk or a network drive.

### 7.15 DoubleSpace and PC-Vault

See section 6.10.

### 7.16 Maximum size of a compressed drive

The maximum size for a DoubleSpace compressed drive is 512 megabytes (MB). For example, if you compress a disk drive that is 600 MB, the resulting DoubleSpace drive will be no larger than 512 MB. To compress the rest of the disk drive, run DoubleSpace, and choose Create New Drive from the Compress menu. Make the new compressed drive as large as possible. (If your drive is very large, you might need to create several new compressed drives in order to compress the entire drive.)

### 7.17 DoubleSpace could not mount a drive due to problems with the drive

If the message "DoubleSpace could not mount drive X due to problems with the drive" (in which X is the drive letter) appears when you start your computer, then the internal organization of the drive has problems that prevent the drive from being used. DoubleSpace stores each compressed drive in a special file called a compressed volume file (CVF). The CVF is a file with the hidden, system, and read-only attributes; it is stored on an uncompressed drive.
To use the compressed drive again, you need to run ScanDisk on that drive's compressed volume file, and then restart your system. The error message includes the name of the compressed volume file on which you need to run ScanDisk (for example, C:\DBLSPACE.000).
To fix this problem for a compressed drive other than drive C:

- Type the SCANDISK command specified by the DoubleSpace error message. For example, SCANDISK D:\DBLSPACE.001. (If MS-DOS cannot find the SCANDISK program, see the following procedure.)

To fix this problem for compressed drive C, or if MS-DOS cannot find the SCANDISK program:

1. Insert Setup Disk 1 in drive A (or B) of your computer.
2. Change to the drive that contains Setup Disk 1.
3. To start ScanDisk, type the SCANDISK command as specified by the DoubleSpace error message. For example, SCANDISK C:\DBLSPACE.000. When ScanDisk displays dialogs describing any problems, choose the Fix It button.
4. After ScanDisk has finished, remove the floppy disk and restart your computer.

### 7.18 DoubleSpace finishes installation, but you cannot access your Hardcard

See section 4.2, part C.

### 7.19 You receive a DoubleGuard Alarm message

If a DoubleGuard Alarm message appears, DoubleGuard has detected that an application has damaged memory that DoubleSpace was using. DoubleGuard halts your computer to prevent any further damage to your data.
Normally, each program "owns" a separate area of memory, and does not use memory that another program is already using. However, a few programs contain programming errors that cause them to inadvertently use memory belonging to another program. If such a program inadvertently uses memory belonging to DoubleSpace, that program could write its own data over the data DoubleSpace was storing there. Since the data that DoubleSpace stores in memory usually includes files you are currently using, this could cause damage to your data.
DoubleSpace's DoubleGuard safety-checking feature detects when another program has violated DoubleSpace's memory, and immediately shuts down your computer to minimize the chance of data loss. (If further disk activity were to occur instead, you could lose some or all of the data on your drive, since the data DoubleSpace has in memory is probably invalid due to damage by the other program.)
If you receive a DoubleGuard Alarm message, do the following:

1. Restart your computer by turning the power switch off and then on again.
2. Type the following at the command prompt:

   `SCANDISK /ALL`

   This runs ScanDisk on all your drives to detect and correct any problems that might have been caused by the program that violated DoubleSpace's memory.
3. Make a note of which program, if any, you were running when the DoubleGuard Alarm occurred. That program is probably (but not necessarily) the program that caused the DoubleGuard Alarm. If you receive additional DoubleGuard Alarms, take notes about what you were doing and see if you can detect a pattern.

### 7.20 A compressed drive is currently too fragmented to mount

If you receive the message "Compressed drive X is currently too fragmented to mount" (in which X is the drive letter) when your computer starts, or if DoubleSpace displays the message "The X:\DBLSPACE.nnn file is too fragmented to mount," then DoubleSpace cannot mount the drive because its compressed volume file is stored in too many fragments on your hard disk. (DoubleSpace stores each compressed drive in a special file called a compressed volume file (CVF). The CVF is a file with the hidden, system, and read-only attributes, and is stored on an uncompressed drive.)
To correct this problem, increase the MaxFileFragments setting in your DBLSPACE.INI file. DoubleSpace displays the "too fragmented to mount" error messages because the number of CVF file fragments exceeds this setting. Follow these steps:

1. Change to the root directory of your startup drive. (If your startup drive is compressed, change to that drive's host drive.)
2. Type the following command:

   `TYPE DBLSPACE.INI`

3. Note the current value for the MaxFileFragments setting.
4. Use the DBLSPACE /MAXFILEFRAGMENTS command to specify a higher value. For example, if MaxFileFragments is currently set to 128, you might type the following command:

   `DBLSPACE /MAXFILEFRAGMENTS=200`

5. Restart your computer. DoubleSpace should now be able to mount the drive.

If DoubleSpace still cannot mount the drive, follow these steps:

1. Run ScanDisk to check the reliability of your hard disk by typing the following at the command prompt:

   `SCANDISK /ALL /SURFACE`

2. Restart your computer. If DoubleSpace still cannot mount the drive, proceed to step 3.
3. Remove the Read-Only, System, and Hidden file attributes on the DBLSPACE.<XXX> file. For example, if the file is H:\DBLSPACE.000, type the following at the command prompt:

   `ATTRIB H:\DBLSPACE.000 -R -S -H`

4. Run Microsoft Defragmenter (Defrag) by typing DEFRAG at the command prompt.
5. Use the ATTRIB command to reset the file attributes on DBLSPACE.<XXX>. For example, if the file is H:\DBLSPACE.000, type the following at the command prompt:

   `ATTRIB H:\DBLSPACE.000 +R +S +H`

6. Restart your computer again. DoubleSpace should now be able to mount the compressed drive.

### 7.21 DoubleSpace displays the message "Your computer is running with an incompatible version of DBLSPACE.BIN"

If you try to run the MS-DOS 6 version of DBLSPACE.EXE with MS-DOS 6.2, it displays the following message:
Your computer is running with an incompatible version of DBLSPACE.BIN.
You must update DBLSPACE.BIN on the root directory of drive @.
DBLSPACE.EXE has detected that its version number does not match that of your MS-DOS 6.2 DBLSPACE.BIN. To correct this problem, you need to update this copy of the DBLSPACE.EXE file.
When you run MS-DOS 6.2 Setup, it updates the DBLSPACE.EXE file in the directory that contains your MS-DOS files. If there are other copies of DBLSPACE.EXE elsewhere on your disk -- for example, in the root directory of your host drive -- Setup does not update those additional copies. To update them yourself, use the COPY /Y command to copy the MS-DOS 6.2 version of DBLSPACE.EXE over the older versions. (The MS-DOS 6.2 version of DBLSPACE.EXE is located in the directory that contains your MS-DOS files.)

### 7.22 Using the DBLSPACE command after bypassing DBLSPACE.BIN

If you bypass DBLSPACE.BIN when you start your computer (by pressing CTRL+F5 or CTRL+F8), then the DBLSPACE command may not work as expected:

- Usually, if DoubleSpace is installed, typing `DBLSPACE` runs the DoubleSpace program. However, if you type `DBLSPACE` when DBLSPACE.BIN is not loaded, DoubleSpace Setup starts instead. If this happens, quit DoubleSpace Setup.
- If you type the `DBLSPACE /MOUNT` command, it reports that there are no more drive letters for DoubleSpace to use. (DoubleSpace cannot mount a compressed drive unless DBLSPACE.BIN is loaded.)

To use DoubleSpace or your compressed drives, restart your computer without bypassing DBLSPACE.BIN.

### 7.23 Removing the write-protection from a compressed floppy disk

If you are using a compressed floppy disk that is write-protected and Automounting is enabled, the disk will remain write-protected until it is unmounted -- even if you remove the write-protect tab from it.
To remove the write protection, use either of the following methods:

- Unmount the floppy disk by using the DBLSPACE /UNMOUNT command, and then try using the disk again (this will automatically remount it). For example, if the disk is in drive B, you would type `DBLSPACE /UNMOUNT B:` and then try using the disk again. (If Windows is running, you can't use the DBLSPACE /UNMOUNT command. In that case, use the following method.)
- Insert a different floppy disk in the drive and access it (for example, carry out the DIR command on it). This automatically unmounts the compressed floppy disk that was previously in the drive.) Then, reinsert the compressed floppy disk and try using it again (this will automatically remount it).

### 7.24 Automounting and Norton disk-caching utilities

If you use a Norton disk-caching utility such as Norton Cache (NCACHE2.EXE) or Norton Speedrive (SPEEDRV.EXE) make sure the utility is loaded after the DEVICE command for DBLSPACE.SYS. If you load one of these utilities before DBLSPACE.SYS, DoubleSpace's automounting feature will not work.

### 7.25 Undelete utilities and DoubleSpace

DoubleSpace cannot compress or uncompress drives while an undelete utility (for example, Microsoft Undelete's Delete Sentry or Norton's SmartCan) is running. To compress or uncompress a drive, you will need to temporarily disable the undelete utility. Follow these steps:

1. Purge any previously deleted files to conserve disk space. If you are using Microsoft Delete Sentry, type the following at the command prompt:

   `UNDELETE /PURGE`

   Carry out this command on each drive you plan to compress or uncompress. If you will be uncompressing a drive, you should also purge deleted files from that drive's host drive. To purge deleted files from a drive other than the current drive, specify the drive letter after the UNDELETE /PURGE command (for example, UNDELETE /PURGE E:).
   L If you use a different undelete utility, see that utility's documentation for information about purging deleted files.
2. Edit your AUTOEXEC.BAT file and use the REM command to disable the command that starts the undelete utility. (For example, if you use Delete Sentry, disable the UNDELETE /S command.)
3. Restart your computer.
4. Try again to compress or uncompress the drive.
5. When you have finished compressing or uncompressing, edit your AUTOEXEC.BAT file, reenable the command that starts the undelete utility, and then restart your computer again.

Additional query words: msbackup 6.20 dblguard bbsstepup stepup

Keywords: kbinfo KB105614