
From: gordonf@vcn.bc.ca (Gordon Fecyk)
Newsgroups: comp.os.ms-windows.win95.misc,comp.os.ms-windows.setup.win95,comp.os.ms-windows.networking.win95,comp.os.ms-windows.apps.compatibility.win95,comp.answers,news.answers
Subject: Windows 95 Frequently Asked Questions and Answers Part 11 of 14
Followup-To: comp.os.ms-windows.win95.misc,comp.os.ms-windows.setup.win95,comp.os.ms-windows.networking.win95,comp.os.ms-windows.apps.compatibility.win95
Date: 14 May 1996 01:48:11 GMT
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Summary: These postings list many questions asked in said newsgroups,
         and answers them as best as I can.  I make references to other
         Web sites and FAQs when appropriate.  Visit the WWW home of
         this FAQ (http://www.intouch.bc.ca/win95) for the appropriate
         links.  This section is the 11th one: Disk Compression
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Archive-name: windows/win95/faq/part11
Last-Modified: 1996/04/29
URL: http://www.intouch.bc.ca/win95/faq11.htm


11) Disk compression and you 

Why should I bother? (Actually it's not as dumb as you might 
think) 
I heard that using disk compression is helpful on drives > 1 GB. Is 
this true? (yes.) 
How do I compress my whole hard drive? (Avoid if possible!) 
How do I compress a part of my hard drive? 
How to make a compressed volume, and keep your Win95 
installation OFF it 
How do I compress floppy disks? 
Enabling "Auto-mount" for removable compressed disks 
The DriveSpace driver takes 60 KB and I can't load it high! How 
do I do it? 
The DriveSpace 3 driver takes 100 KB and I can't load it high! 
How do I do it? 
How do I start my computer WITHOUT loading the DriveSpace 
driver? 
Why you should run DOS programs in DOS sessions in Win95 
How do I load the Win95 DriveSpace driver, but NOT load 
the DOS DriveSpace driver? 
My computer is very, very, slow since I installed disk 
compression. How can I speed it up? 
Basic DriveSpace 3 theory; regular, HiPack, UltraPack, 
Compression Agent 
Why on slow computers, you should use "No compression" 
and still use DriveSpace 3 
Top ten mistakes using disk compression 
Top ten mis-conceptions regarding DriveSpace 3 
----------------------------------------------------------------------

Why should I bother? (Actually it's not as dumb as you might 
think) 

With hard drives getting cheaper every day, you will believe (and I do 
too) that disk compression is a waste of processor time, a waste of 
system memory, and it makes the system unstable. But, here are some 
good reasons to use disk compression: 

On FAT file systems, it wastes far less disk space (Cluster sizes are 
minimum 512 bytes regardless of the partition's 'reported' cluster size) 

It reduces the amount of CPU time spent on the hard drive (It reads 
less off hardware) 

It makes good use of smaller hard drives 

Win95's disk compression take NO conventional memory (At least, 
when you run Win95 that is) 
----------------------------------------------------------------------

I heard that using disk compression is helpful on drives > 1 GB. 
Is this true? 

DriveSpace 3, in particular, is helpful for drives > 1 GB, if you set 
compression to "none". This is because DriveSpace will use a smaller 
physical cluster size. 

Normally, FAT file systems have a 65 thousand cluster limit (64 K, or 
65 535 clusters); this means as the drive gets bigger, the cluster size 
gets bigger too. On a 1 GB hard drive, the cluster size is 32 KB! 
That's a lot of disk space wasted if your file is much smaller than 32 
KB! 

DriveSpace (and Stacker, and what-have-you) use their own file 
system and emulate FAT, and they can compress the unused space in 
a cluster. DriveSpace 3, in particular, will use no more than 512 bytes 
per simulated cluster, if your file is smaller than this. 

You can observe this by running DEFRAG on a compressed drive in 
Win95; after the inital defrag pass, it will de-fragment a second time, 
showing the relative sizes of each cluster. Tightly compressed clusters 
will appear shorter. 
----------------------------------------------------------------------

How do I compress my whole hard drive? 

I say Avoid If Possible. If you have to re-install Win95, you might not 
be able to read the compressed drive to perform the re-installation 
on! 

However, it can be done. You will have to have Disk Compression 
installed in Win95; check Add/Remove Programs/Windows 
Setup/Disk Tools. Then, right-click on your target hard drive and 
bring up its properties. You should see a Compression tab which 
gives you two options. Select the option to compress the whole hard 
drive. 

This built in compression (Affectionately called "DriveSpace 2") will 
re-boot your computer and run a compression process in a 
"miniature" Windows 3.1 environment. This means you can't use your 
computer while this happens. This does take a long time, so you 
should get it started and let it run overnight. When completed, you will 
have two active drive letters, or volumes; your original hard drive 
(Re-named to "H:" or some such thing) and your new compressed 
hard drive (Renamed "C:" to replace your original hard drive). 
----------------------------------------------------------------------

How do I compress a part of my hard drive? 

OK so you heeded my warning. Good. You have to install Disk 
Compression if you didn't already do so. Before running DriveSpace, 
de-fragment the hard drive you're placing the compressed volume on. 
This will maximize the space the compressed volume can take. 

Then, bring up properties of the target hard drive. In the Compression 
tab, select the option to create a new compressed volume. This will 
run DriveSpace, create the new .CVF file, and tell you to re-boot 
your computer. Much quicker. 

If you plan to use DriveSpace this way, you should do so right after 
you complete your Win95 installation, and create a compressed 
volume with all the remaining space. This will maximize the drive 
space that gets compressed, and keep your Win95 installation 
un-compressed, ready to re-install if necessary. Maybe leave about 
100 MB un-compressed for the Program Files folder, which always 
goes on your booting drive. 
----------------------------------------------------------------------

How do I compress floppy disks? 

Bring up properties for your floppy drive, and select the 
"Compression" tab. You only have one compression option here; you 
can't put a separate CVF on a floppy disk. The rest of it works like 
compressing your whole hard drive. 

It's best to do this with blank disks; otherwise you will waste time 
compressing the files already on the floppy. Use this technique for any 
other removable media; optical disks, SyQuest disks, whatever. 
----------------------------------------------------------------------

Enabling "Auto-mount" for removable compressed disks 

Back in DOS 6.0, you had to manually mount compressed floppies, 
and un-mount them before ejecting them. Win95 will automatically 
mount compressed floppies if you allow it to. 

Run DriveSpace, then in Advanced/Settings, turn on the Auto-Mount 
switch. This is normally turned on by default. The first time you access 
the removable disk, if it sees a DRVSPACE.xxx file, it will use that 
instead of the actual disk. 

No, you can't copy .CAB files to compressed floppies; the files in a 
CAB are already compressed. 
----------------------------------------------------------------------

The DriveSpace driver takes 60 KB and I can't load it high! 
How do I do it? 

In order for Win95 to actually start, Win95 DOS has to see any 
compressed drives you might have installed Win95 on. There is a real 
mode DriveSpace driver (and a real-mode DRVSPACE.INI settings 
file) in the root of your boot drive, though they're hidden. 

If you have an empty CONFIG.SYS file (which you should), when 
Win95 starts it will remove the real mode DRVSPACE.SYS driver 
and run the protected mode driver in its place, freeing up the 60 KB. 

If you insist on keeping a DOS configuration (Or if you specified a 
special DOS config for any of your games), you can continue to use 

DEVICEHIGH=%WINDIR%\COMMAND\DRVSPACE.SYS /MOVE

to re-locate the real mode driver to upper memory. 
----------------------------------------------------------------------

The DriveSpace 3 driver takes 100 KB and I can't load it high! 
How do I do it? 

Ahh... monster driver! This thing is so big because it needs to have 
compression routines for the three types of compression: UltraPack, 
HiPack, and Standard. 

If you have enough upper memory, make the DRVSPACE.SYS 
/MOVE entry in CONFIG.SYS the very next DEVICE= right after 
EMM386. This will eat 100 KB of upper memory of course, and the 
rest of your real mode drivers probably won't fit in upper memory 
afterwards. 

Win95 will un-load this monster driver from conventional memory 
when you run Win95, provided you didn't try to load it high. Do 
yourself a favor and run your DOS programs in DOS sessions. 
----------------------------------------------------------------------

How do I start my computer WITHOUT loading the 
DriveSpace driver? 

Edit MSDOS.SYS and add or edit these lines to the [options] 
section: 

drvspace=0
dblspace=0

and re-boot. 

NOTE: If you do this, you can't access compressed drives from DOS 
of course, but you also can't access them in Win95 either! This is an 
important reason not to compreess your whole hard drive. 
----------------------------------------------------------------------

How do I load the Win95 DriveSpace driver, but NOT load the 
DOS DriveSpace driver? 

Actually, there IS a way NOT to load the DriveSpace driver in 
MS-DOS Mode, AND use the compressed drive in Win95! You'll 
find this trick useful if you run many programs in Single Mode DOS or 
make up special DOS configurations for certain programs and games, 
as it saves a good 60 KB to 100 KB of conventional memory, and 
still lets you use the compressed drive under Win95 and in DOS 
sessions. 

This is a bit tricky, so only do it if you know what you're doing, AND 
you aren't picky about what drive letter the compressed drive takes, 
AND you didn't install Win95 on the compressed drive, AND you 
don't assign any network shares on the compressed drive (You'd have 
to re-share them each time you re-boot if you did this.) 

1) Put in the entries to MSDOS.SYS above 

2) Run Policy Editor, Select File/Open Registry, and in Local 
Computer/System/Run Services, add this entry: 

       Name: Manually mount DriveSpace Drive (Actually you can call this what you want)
       Value: DRVSPACE.EXE /MOUNT=001 C:

3) Save changes to the Registry, and test by re-booting to "Command 
Prompt Only" (Press F8 on "Starting Windows 95..."). Check that 
you have lots of conventional memory free. 

4) Type WIN to start Win95. Before any other programs load, you 
should get some floppy access and a message stating that your 
compressed drive has mounted. 

5) Now you can re-boot normally, once you're sure everything 
works. 

What this does, is prevent the real mode DriveSpace driver from 
loading at all. Again, this means you can't access compressed drives 
outside of Win95. It also mounts the compressed drive, using 
protected mode drivers, before any other Win95 programs start (Run 
Services runs its programs before anything else does). You will get an 
annoying message on start up, but you had to pay the price 
somewhere for this cool trickery, no? 

Syntax of DRVSPACE.EXE /MOUNT command: 

DRVSPACE /MOUNT=xxx y: /NEW=z:

Where "xxx" is the number of the compressed volume (Find out by 
showing all files and looking for a DRVSPACE.001 file; the 001 is 
the number you put in the MOUNT= parameter). "y:" is the drive 
letter where the compressed volume exists. "z:" is the drive letter you 
assign the new compressed drive in the /NEW= parameter. NOTE: 
/NEW= does not always pick the drive letter you want, especially if 
you have network drives. It's best to leave out the /NEW= and just 
live with the drive letter it comes up with. You can specify a range of 
drive letters in the DRVSPACE.INI file, if you choose, to make the 
assignment consistent. Once it settles on a drive letter it will 
consistently use it, until you remove the compressed drive or re-assign 
the drive letter. 
----------------------------------------------------------------------

My computer is very, very, slow since I installed disk 
compression. How can I speed it up? 

DriveSpace works best in Win95 if you have lots of RAM (16 MB), 
have lots of extra computing power ('DX2-66es are quite adequate 
for this), and some external SRAM for processor caching (256 KB is 
best). The CPU has to work harder to interpret compressed data, but 
it has to wait less time to actually get it. This is the trade-off. 

To speed compressed drives up, install DriveSpace 3 (in MS Plus!), 
and set compression to "none", or "none, unless it is xx% full, then use 
Standard". You still get the benefits of reduced cluster sizes even 
though you aren't compressing data. Later on, you can use 
Compression Agent to compress the drive overnight, or any other 
time you aren't using the computer. 

If you use DriveSpace 3 on a '486 class computer, do not use HiPack 
as the default file format, as MS recommends. Maybe even set 
compression to "None" and use Compression Agent to re-compress 
overnight, using HiPack then. HiPack takes less time to read than to 
write. Also, when using Compression Agent, DO NOT USE 
UltraPack! UltraPack is very, very, slow on '486 machines. I wouldn't 
even recommend it for Pentium machines slower than 100 MHz. 

If you're too cheap to buy MS Plus, simply make sure your swap file 
isn't on the compressed drive, and it's set to a fixed size. Do this from 
System Properties/Performance/Virtual Memory. Win95 doesn't 
actually compress the swap file, but it does go through the 
DriveSpace driver to access it. Move it to an uncompressed drive to 
remove that extra layer of protocol. 

Finally, make sure you have NO real mode disk drivers to handle 
CD-ROMs, etc, that might be sitting on the hard drive adapters. The 
Win95 disk driver can't load then, and it won't use the Win95 
DriveSpace driver either. 
----------------------------------------------------------------------

Basic DriveSpace 3 advice; regular, HiPack, UltraPack, 
Compression Agent 

DriveSpace 3 makes more drive space by compressing files tighter. It 
does so using Compression Agent, which gets automatically 
scheduled in System Agent when you install MS Plus. 

Run DriveSpace 3, select the compressed drive, then select 
Advanced/Settings. This selects how DriveSpace writes data to the 
compressed drive on the fly. As MS recommends, don't use HiPack 
on '486 class computers. I won't even use it on Pentium-75s. 
"Standard" is best for all '486 machines or better, though a slow '486 
can benefit from the "None until..." setting. Use "None" on all '386 
class machines. 

Now, DriveSpace 3 can un-compress data faster than it can 
compress it, so it makes sense to try to re-compress the drive during 
idle moments, like overnight. Compression Agent does this. 

Either in System Agent, or in Accessories/System Tools, run 
Compression Agent and hit its Settings button. For Pentiums faster 
than 100 MHz, you could try UltraPack, but I doubt you'll get a 
whole lot of extra disk space from it. All '486 systems can benefit by 
completely turning off UltraPack and specifying HiPack for the rest of 
the files (basically meaning "All of them".) Generally, reading back 
HiPacked files is quick, so you can specify that for even '386 class 
machines, but if you really can't handle the decrease in speed, use 
"Store them un-compressed". 

A re-compression run does take a LONG time, so do it overnight. 
Use System Agent to schedule re-compression, say, once a month, 
and schedule a thorough disk scan about an hour before Compression 
Agent runs. 
----------------------------------------------------------------------

Why on slow computers, you should use "No compression" and 
still use DriveSpace 3 

It handles bigger hard drives (compressed volumes larger than 512 
MB) 

It reduces wasted disk space (for files smaller than 512 bytes, it only 
occupies 512 bytes, regardless of logical cluster size) 

It won't eat CPU time if you turn compression off 
----------------------------------------------------------------------

Top ten mistakes using disk compression 

10) Running your DOS games outside of Win95 (Not enough 
memory) 

9) Deleting the DRVSPACE.001 file (Fortunately, Win95 has a 
safety mechanism for that!) 

8) Deleting the DRVSPACE.BIN file 

7) Using an old DOS compression program (Sorry Stac Electronics... 
you lose here) 

6) Using a DOS driver for your IDE CD-ROM and DriveSpace (Get 
Win95 drivers for the IDE port and it'll find the CD-ROM) 

5) Not using ScanDisk regularly (Use System Agent to do automatic 
disk scans) 

4) Setting your estimated compression ratio higher than your real one 
(Then installing a big game...) 

3) Using UltraPack on a '386 computer 

2) Using Norton Disk Doctor for Win95 on DriveSpace 3 drives 
(ScanDisk is more reliable... Symantec released _two patch sets_ to 
fix Norton Utilities) 

1) Compressing your whole hard drive 
----------------------------------------------------------------------

Top ten mis-conceptions regarding DriveSpace 3 from MS Plus 

10) Norton Utilities for Win95 works on it (Sorry... it reported false 
errors on mine!) 

9) It's faster than "DriveSpace 2" (At least not at first...) 

8) I need a Pentium-133 to use it (Just don't use UltraPack) 

7) It eats more conventional memory (Actually, it eats NONE under 
Win95, if set up properly) 

6) I can compress my whole drive with it (Yeah... then try re-installing 
Win95) 

5) It's useless on '386 machines 

4) It makes my computer un-stable (use System Agent to schedule 
disk scans) 

3) A virus can wipe out the system (A nasty virus could wipe out the 
system, compressed or not) 

2) MS deliberately crippled Win95's built-in DriveSpace to make us 
buy MS Plus 

1) It's the best compression program for Win95 (Actually, it's the 
ONLY one... heh heh) 
----------------------------------------------------------------------

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