Q97741: Optimizing DoubleSpace on Your Computer
Article: Q97741
Product(s): Microsoft Disk Operating System
Version(s): MS-DOS:6.0,6.2,6.22; WINDOWS:95
Operating System(s):
Keyword(s): msdos win95kbfaq
Last Modified: 17-DEC-2000
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The information in this article applies to:
- Microsoft MS-DOS operating system versions 6.0, 6.2, 6.22
- Microsoft Windows 95
- Microsoft Plus! for Windows 95
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SYMPTOMS
========
NOTE: This information applies to both Microsoft DoubleSpace and Microsoft
DriveSpace. For MS-DOS 6.22, Windows 95, and Microsoft Plus!, use DRVSPACE in
place of DBLSPACE in all commands and file names.
After you use DoubleSpace to compress your hard disk, you may experience one or
more of the following symptoms:
- You may have less free conventional memory. As a result, you may be unable to
run one or more MS-DOS-based programs. If you are running Windows 95 or
Microsoft Plus! DriveSpace, the problem may occur only when you restart your
computer in MS-DOS mode or boot to a Windows 95 command prompt.
- You may experience a slight performance degradation.
CAUSE
=====
To provide access to compressed drives, DoubleSpace loads a real-mode device
driver that requires a considerable amount of memory. If your computer is not
configured to provide access to the upper memory area (UMA), the DoubleSpace
driver must load in conventional memory.
Windows 95 and Microsoft Plus! include both real-mode and protected-mode
DriveSpace drivers. The real-mode DriveSpace driver is used to provide access to
compressed drives before Windows 95 starts and when you restart your computer in
MS-DOS mode or boot to a Windows 95 command prompt. The protected-mode
DriveSpace driver is used after Windows 95 starts to provide protected-mode
access to compressed drives.
Because the protected-mode DriveSpace driver replaces the real-mode driver in
memory after Windows 95 starts, the amount of conventional memory used by the
real-mode driver is normally not a concern when you are running MS- DOS-based
programs in Windows 95. However, if you frequently run MS-DOS- based programs
after restarting the computer in MS-DOS mode or after booting to a Windows 95
command prompt, you may find that programs requiring large amounts of
conventional memory are unable to run.
The primary reason for performance degradation while running compression software
such as DoubleSpace is that each time a read or write is made from or to the
hard disk, data must be decompressed or compressed. This decompression or
compression of data places additional demand on the processor in your computer.
Computers with faster processors most likely will not experience performance
degradation after compression software is installed.
RESOLUTION
==========
To resolve the problem, refer to the appropriate section below.
MS-DOS 6.0, 6.2, or 6.22
------------------------
To work around this problem when you are running MS-DOS 6.0, 6.2, or 6.22
DoubleSpace or DriveSpace, follow these steps:
1. If you are using Microsoft Windows, set the TEMP environment variable to the
host drive. To do so, follow these steps:
a. Type "dblspace /list" (without the quotation marks) at a command prompt
and then press ENTER to determine which drive is the host drive.
b. Use the DIR command to determine if you have at least two megabytes (MB)
of free disk space on the host drive. If you do not, see the section
titled "Using DoubleSpace to Manage Compressed Drives" in the "User's
Guide" for instructions on decreasing the size of the compressed volume
file (CVF). If you receive the message "Drive X is too fragmented to
resize," see section 7.14 in the Readme.txt file.
c. Change to the host drive and create a TEMP directory. For example, if your
host drive is drive H, type the following lines at a command prompt,
pressing ENTER after each line:
" h:
md \temp" (without the quotation marks)
d. Using a text editor such as MS-DOS Editor, edit the Autoexec.bat file and
change the SET TEMP statement to point to the TEMP directory on the host
drive. For example:
set temp=h:\temp
2. If your computer contains an 80386 or higher processor, run MemMaker after
you run DoubleSpace to ensure you are freeing as much convention- al memory
as possible. If you have a VGA display adapter, run MemMaker in custom mode
and choose Yes when you are prompted to use the mono- chrome region to obtain
an additional 32K of upper memory block (UMB) space. If you have a Super VGA
video display adapter, you can use the monochrome region, but you need to
load the Monoumb.386 file if you use Microsoft Windows. For specific
instructions, see section 2.3 of the Readme.txt file.
3. If your computer contains an 80286 processor and is low on conventional
memory, consider purchasing a third-party memory manager to load device
drivers, terminate-and-stay-resident (TSR) programs, and the Double- Space
component (Dblspace.bin) in the upper memory area (UMA).
4. If your computer contains an 80286 or higher processor and has more than 1 MB
of memory, ensure you are loading SMARTDrive.
5. If you are unable to run a particular program (such as an MS-DOS-based game)
due to insufficient memory, you may want to move that software to the host
drive and create a startup disk for drive A that does not contain the
DoubleSpace component. To do so, follow these steps:
a. Type "dblspace /list" (without the quotation marks) at a command prompt
and then press ENTER to determine which drives are uncompressed or host
drives.
b. Use the XCOPY command to copy the program's directory to the host drive.
For example, if drive H is your host drive, type "xcopy c:\dir\*.*
h:\dir\*.* /s" (without the quotation marks) at a command prompt and then
press ENTER.
c. Create a bootable floppy disk in drive A with the SYS command. For
example, type "sys c: a:" (without the quotation marks) at a command
prompt and then press ENTER.
d. Type "deltree a:\dblspace.bin" (without the quotation marks) at a command
prompt and then press ENTER to remove the DoubleSpace component.
e. Confirm that all the files were copied to the host drive.
f. Using a text editor such as MS-DOS Editor, create Config.sys and
Autoexec.bat files on drive A and include any TSRs or device drivers
required by the program. You should also add a PATH statement to include
the program's directory.
NOTE: If you are using a host drive, remember that the drive letter is
different when you start the computer without the DoubleSpace component.
g. Restart the computer with the new startup disk in drive A and run the
program to ensure you have configured the system correctly.
NOTE: Your compressed drive will not be accessible when you restart your
computer from this floppy disk. However, the data on your drive is not
lost. It will be accessible when you restart your computer from the hard
disk.
h. If everything is functioning correctly, restart your computer from the
hard disk and delete the program's directory from the compressed drive.
For example, type "deltree /y c:\dir" (without the quotation marks) at a
command prompt and then press ENTER.
6. Some programs either implicitly (such as Microsoft Mail version 3.0) or
explicitly (such as Paradox) encrypt data files. This encryption removes any
patterns in the data, rendering it incompressible. Storing these files on a
DoubleSpace drive does not save any disk space and increases file write time
because DoubleSpace does the work of trying to compress the file, but cannot.
These types of files, if updated often, should be stored on a uncompressed or
host drive.
Windows 95 or Microsoft Plus!
-----------------------------
Optimizing Performance with Windows 95 or Microsoft Plus! DriveSpace:
To optimize your computer's performance while running Windows 95 or Microsoft
Plus! DriveSpace, follow these steps:
1. Verify that the protected-mode DriveSpace driver is being used in Windows 95.
To do so, double-click the System icon in Control Panel, and then click the
Performance tab. If the Disk Compression line indicates that compressed
drives are using MS-DOS Compatibility mode, the protected-mode DriveSpace
driver is not being used.
To cause the protected-mode DriveSpace driver to load when Windows 95 starts,
follow these steps:
a. Make sure that the Drvspacx.vxd file is present in the Windows\
System\Iosubsys folder. If the file is not present, extract it to that
folder from the Win95_09.cab cabinet file on the original Windows 95
CD-ROM or disk 9, or from the Plus_1.cab cabinet file on the original
Microsoft Plus! CD-ROM or disk 1.
For information about using the Extract tool, type "extract" (without the
quotation marks) at a command prompt, or see the following article in the
Microsoft Knowledge Base:
Q129605 How to Extract Original Compressed Windows Files
b. Copy the Drvspace.bin file from the Windows\Command folder to the root
folder of the boot drive as both Drvspace.bin and Dblspace.bin. To do so,
type the following lines at a command prompt, pressing ENTER after each
command
" copy c:\windows\command\drvspace.bin <drive>:\drvspace.bin /y
copy c:\windows\command\dblspace.bin <drive>:\dblspace.bin /y" (without
the quotation marks)
where <drive> is the physical boot drive. If drive C is compressed,
copy the Drvspace.bin file to the root folder of the host drive for drive
C instead of the root folder of drive C.
NOTE: The /Y switch causes the COPY command to replace existing files
without prompting you for confirmation.
After performing these steps, restart your computer and check to see if the
problem has been resolved. If it has not, perform the following additional
step:
c. If you did not extract the Drvspacx.vxd file in step A because it already
exists in the Windows\System\Iosubsys folder, extract it now. In addition,
extract the Drvspace.bin file from disk 1 or the CD-ROM to the
Windows\Command folder. After extracting this file, repeat step B.
2. Verify that the hard disks are not badly fragmented. Badly fragmented hard
disks can affect the performance of DriveSpace 3, as well as the performance
of other Windows 95 components. To ensure that your hard disks are not badly
fragmented, run Disk Defragmenter to defragment them. To run Disk
Defragmenter, click the Start button, point to Programs, point to
Accessories, point to System Tools, and then click Disk Defragmenter.
3. Verify that the drive containing your Windows folder and the Windows swap
file contains sufficient free disk space. For information about creating
additional free disk space, view the "Disk Space Trouble- shooter" topic in
Windows 95 Help.
Optimizing Conventional Memory for MS-DOS-Based Programs:
If you are unable to run an MS-DOS-based program when you restart your computer
in MS-DOS mode or boot to a Windows 95 command prompt after running Windows 95
or Microsoft Plus! DriveSpace, reconfigure Windows 95 so that more conventional
memory is available. To do so, use one of the following methods:
- If you are running an MS-DOS-based program after restarting your computer in
MS-DOS mode, modify the Config.sys and Autoexec.bat files that are used when
the computer restarts in MS-DOS mode so that more conventional memory is
available. You should modify the Config.sys and Autoexec.bat files that are
specified in the properties for the program you are running in MS-DOS mode,
the properties for the shortcut that starts the program you are running in
MS-DOS mode, or the properties for the "Exit to Dos.pif" file that is used to
start Windows 95 in MS-DOS mode.
Use the following steps to modify the Config.sys and Autoexec.bat files that
are used when the computer restarts in MS-DOS mode so that more conventional
memory is available. After performing each step, check to see if you are able
to run the MS-DOS-based program.
a. Make sure that the Config.sys file that is used when the computer restarts
contains lines similar to the following (in the following order):
DEVICE=C:\WINDOWS\HIMEM.SYS
DEVICE=C:\WINDOWS\EMM386.EXE NOEMS
DOS=HIGH,UMB
DEVICEHIGH=C:\WINDOWS\COMMAND\DRVSPACE.SYS /MOVE
These lines make it possible for the real-mode DriveSpace driver to load
into upper memory, which can free more conventional memory for
MS-DOS-based programs.
NOTE: If your MS-DOS-based program requires expanded memory, please see the
program's documentation for information about how to configure Emm386.exe
to provide expanded memory.
b. Try loading device drivers in the Config.sys file using the DEVICEHIGH
command instead of the DEVICE command. In addition, try loading
memory-resident programs in the Autoexec.bat file using the LOADHIGH
command.
c. Remove any unnecessary drivers and memory-resident programs from the
Config.sys and Autoexec.bat files that are used when you restart your
computer in MS-DOS mode.
- Use the Microsoft Startup Disk Wizard (Nocomp.exe) that is included with
Microsoft Plus! to create a bootable floppy disk that does not load the
real-mode DriveSpace driver. To run an MS-DOS-based program after booting
from the floppy disk created by the Microsoft Startup Disk Wizard, the
program must be installed on an uncompressed drive.
MORE INFORMATION
================
The DriveSpace compression drivers included with Windows 95 contain
processor-specific code designed for optimal performance on 80386 and 80486
processors. In addition, the DriveSpace 3 compression drivers included with
Microsoft Plus! contain code designed for optimal performance on Pentium
processors. The compression drivers included with Windows 95 and Microsoft Plus!
detect the type of processor that a computer is using and then use the
appropriate code.
Microsoft Plus! includes DriveSpace 3, which is an enhanced version of DriveSpace
that supports the ability to fine-tune compression for maximum disk space,
maximum system speed, or a balance between disk space and system speed. If
system performance is your primary concern, DriveSpace 3 can be configured
accordingly, but doing so will cause your files to take up considerably more
disk space.
Additional query words: 6.00 6.20 6.22 slow Ultima 6 Commander Keen Serpent Great Battles of the NorthWest
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Keywords : msdos win95 kbfaq
Technology : kbWin95search kbGamesSearch kbPlusSearch kbZNotKeyword3 kbPlus95 kbMSDOSSearch kbMSDOS622 kbMSDOS620 kbMSDOS600
Version : MS-DOS:6.0,6.2,6.22; WINDOWS:95
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