CHAPTER 6

Working with your Stacker drive

 

Now that you have a Stacker drive in the belly of your PC, what's it all about? For the most part, using a Stacker drive is identical to using an un-stacked drive. The installation process ensures that everything behaves the same as it did before, which leaves more room on your disk for files and less room in your brain for Stacker-related headaches. Yet, there are some important things you should be aware of when using your Stacker drive.

This chapter covers several important issues about using a Stacker drive with your PC. They're covered in the following four sections: 

 

Improving Stacker drive performance

 

With all the blessings of greater disk storage, what more could you possibly want from your Stacker drive? This is where the issue of performance rears its slobbery head. While Stacker does double disk space, it adds to the time your computer takes to read and write information to disk. This is called overhead. Another performance issue is compression. Some files will shrink down better than others. The next few pages will bring these issues to light and help you keep the slobbering performance demon at bay.

 

Checking a Stacker drive with CHECK

 

The CHECK utility is a general-purpose Stacker drive checking program, similar to DOS's Check Disk (CHKDSK) program but more practical. (In older versions of Stacker it was called SCHECK.) CHECK tells you that your Stacker drive is doing okay, describes how the drive is used, gives performance information, and detects any potential errors.

To use CHECK, type CHECK at the DOS prompt followed by the letter of the Stacker drive you want to check. (If you don't specify a drive letter, CHECK checks the current drive.) For example:

 

C:\> CHECK C:

 

After pressing Enter, you'll see Performing FAT integrity checks quickly followed by Checking cluster integrity. These appear briefly -- too fast to catch a real glimpse of what they say. Eventually, you should see the following:

 

No errors found

 

This will be followed by the Stacker drive's compression ratio and projected bytes free statistics.

For more detailed information, specify the /D switch. This directs CHECK to perform the same tests, but it also offers a nifty summary screen.  What you see on your screen will look similar to Fig. 6-1.

 

Figure 6-1.  CHECK's output.

 

  You cannot CHECK a networked Stacker drive. If you attempt it, you'll see the same error message that displays when you try to CHECK a non-Stacker drive: Drive x is not a Stacker drive.

 

In Fig. 6-1, drive C is a Stacker drive. It's shown along with its drive label (STACVOL_DSK) and the message No errors found. Below that, you'll find the interesting stuff:  

  The last three values -- compression ratio, projected bytes free, and fragmentation level -- are important to know when calculating a Stacker drive's performance. The compression ratio tells you how much smaller the files are on the Stacker drive. In this example, 1.6:1 was shown. That's a bit shy of the 2:1 ratio Stacker strives for. Consider the following:

 

Stacker Drive Compression Ratio = 16.0:1

 

This figure was obtained from a Stacker RAM drive used to store text files. A 16:1 ratio means the files take up one sixteenth the space they would occupy on a standard disk. The 2:1 ratio means files take up half the space (and, ipso facto, Stacker doubles your disk storage). However, 1.6:1 is a little low. This is good to know for this example, because such a low number can be improved; you'll see how later in this chapter.

The projected bytes free value is interesting because it's a guess. Stacker assumes that all files will be half as big on the Stacker drive. However, not everything turns out that way. Therefore, the total number of bytes that can be stored on a Stacker drive varies. The projected bytes free value is assuming the files you'll be putting on your Stacker drive will shrink at the desired 2:1 ratio. (So, I suppose, ``Your mileage may vary.'')

Finally, the fragmentation level lets you know how many files are stored on the Stacker disk in a fragmented state -- which is also what the Check Disk command tells you about DOS disks.  When that number gets too high, say around ten percent or more, then you'll need to defragment your Stacker drive using the SDEFRAG utility.  Doing that is covered later in this chapter, in the section titled ``Optimizing the Stacker drive.''

If you see an error, it's most likely due to a disk cache installed after Stacker's device driver in CONFIG.SYS or AUTOEXEC.BAT. You can edit the proper file and stick a REM command in front of your cache, reset the PC, then try using CHECK again.

Other errors that might appear indicate something is foul with the Stacker drive. CHECK will give you instructions on what to do next. Typically this means running CHECK again with the /F switch (just like CHKDSK).  The /F switch also directs CHECK to perform a "surface scan" of the drive, which may detect errors the normal CHECK command misses. (A complete list of CHECK's options is given in chapter 9.)

 

   The SETUP program may have inserted the CHECK /WP command into your AUTOEXEC.BAT file.  The /WP switch directs CHECK to perform a quick verification of all Stacker drives in your system.  If done every time you boot your PC, this will catch some heinous errors that may otherwise slip your attention.

 

Checking the compression ratio

 

The compression ratio is an interesting figure. While it's good to know how tightly Stacker is packing in your files, you really can't do much when compression gets low (below 2:1). Compression really is a function of your files and what's in them. However, there are a few stunts you can pull to improve the figures slightly.

To check the overall compression of a Stacker drive, use CHECK. For individual files, however, you can use Stacker SDIR command. This command works quite similarly to the DIR command. Type in SDIR alone or followed by a wildcard or the name of a disk or directory you want to examine. Sample output for SDIR is shown in Fig. 6-2. It looks very similar to the output of the DIR command, save for the extra compression ratio values after a file's date and time.

 

Figure 6-2.  SDIR's output.

 

In Fig. 6-2, you can see how Stacker compressed the text files, CONFIG.SYS and AUTOEXEC.BAT, at a high ratio, 8:1. Program files, such as COMMAND.COM, compress at a lower ratio, 1.4:1 in the figure. Even worse than that are some graphics-format files. At the bottom of the barrel are already-compressed archive files, such as the ZIP and ARC files modem users cherish.

 

Table 6-1.  Files and their compression.

 

Table 6-1 shows several files I copied to my Stacker drive. Shown are the file name, type, and compression ratio as reported by SDIR. Overall, Windows' BMP (bitmap) files show the best compression. This is true for other graphics format files, such as TIFF and EPS. Other files that shrink well include text files, data base files, and some word processing documents. These all usually will store on disk with greater than 2:1 compression.

Below 2:1 compression, you'll find an interesting assortment of files. In Table 6-1, the PCX (PC Paintbrush) file shows the best compression, 1.9:1 is almost the 2:1 Stacker strives for. However, everything else is poor. GIF files -- already compressed graphics files -- take up as much disk space on or off a Stacker drive. The NAKDLADY.GIF file is stored at its full 124,928 bytes; it does no good to put such a file on a Stacker drive. The ARC file shows okay compression; however, ZIP, which packs in more files at a higher compression, shows only a 1.2:1 ratio. (Some ZIP files, specifically self-exploding EXE programs, usually store at a 1:1 ratio on a Stacker drive.)

 

The impressive compression summary

 

CHECK and SDIR are primitive, time consuming utilities.  If you really want to impress your friends -- as well as see the ultimate in Stacker compression statistics -- you can run the REPORT program.  This is something that's unique to version 3 of Stacker. Type REPORT at the command prompt and prepare to be dazzled.

 

C:\STACKER> REPORT

 

   If you don't specify a Stacker drive, then Report prompts for you to select a Stacker drive before it makes its report.  Report will also notify you of any errors and recommend you run the CHECK utility with its /F option on the specified drive.

 

The REPORT program displays highly informative statistics about the files that are using a Stacker drive and the compression ratio of each. The file statistics are organized by file extension, which is the closest thing we have to a "file type" in DOS.  You can view the compression ratio statistics by file extension (EXE programs are most popular in Fig. 6-3); file count, or how many of each type of file are on the disk; disk usage, or the space used by files of various extensions; and compression ratio, which tells you which files compress the best.

To change the view, press the up or down arrow keys.  To view the statistics in ascending or descending order, press the + or - keys accordingly.

 

Figure 6-3.  The REPORT program's display.

 

Figure 6-4.  Here, bar graphs illustrate the Stacker drive's compression ratio.

 

The best visual summary is accessed by selecting the "Show Summary" item at the top of the display.  You do this by pressing the Tab or right arrow keys.  What you'll see is similar to that shown in Fig. 6-4: bar graphs describing the compression ratio of your drive.

The top graph shows your expected compression ratio verses what's actually happening on the Stacker drive.  In Fig. 6-4, my PC is getting only 1.7:1 compression when it should get 2:1.  That means Stacker has only given me 1.7 times my original disk storage space instead of the promised two times.  (This can be helped; see the next section.)

The graphs on the lower part of the screen describe how your Stacker drive and its STACVOL.xxx file are doing.  In Fig. 6-4 my Stacker drive C holds about 11M of data out of a potential 78M.  The STACVOL.DSK file is 38M in size and only about 6M has been used.

The most annoying part of the display is where it says You can increase your uncompressed space by 32,538,112 bytes.  Though it claims I can do that, it doesn't really say how or why.  Fortunately, that information is offered in the next section.

Press F10 and then Enter to exit the REPORT program.

 

Improving lousy compression

 

What can be done about lousy compression? Chances are the best way to improve the situation is to use the TUNER utility.  In your STACKER directory, type TUNER at the command prompt:

 

C:\STACKER> TUNER

 

TUNER doesn't need to be followed with a drive letter since it's adjustments affect all of your Stacker drives.

After pressing Enter, the TUNER program's main screen appears, as shown in Fig. 6-5.  Here you have three options for adjusting Stacker's compression ratio: Select low-compression, which offers the fastest speed; select a moderation of speed and compression; or toss speed into the wind in favor of the best compression possible.

 

Figure 6-5.  The TUNER allows you to adjust Stacker's overall compression.

 

    If you have the Stacker co-processor hardware installed, a fourth option appears in the TUNER's menu (Fig. 6-5): Use Stacker Coprocessor board.  This means Stacker is using its co-processor to get the best of compression and speed out of your Stacker drives.

 

If compression is what you want, highlight the last item in the list and select the Continue button.  TUNER will update your CONFIG.SYS file; select the OK button to return to DOS.

What the TUNER utility does is to add the /P switch to the command that loads STACKER.COM in CONFIG.SYS.  /P is followed by an equal sign and a value ranging from 1 to 9.  Low numbers favor speed over compression, high numbers favor compression over speed.  If you selected Fastest speed and standard compression in the TUNER, then /P=1 is used; if you opted for More compression and a bit less speed, then /P=5 is used; /P=9 is used when you want the Best compression.  You can manually edit CONFIG.SYS and change the /P value to other numbers for further tweaking.

Since CONFIG.SYS has been modified, you'll need to reset your PC for the changes to have affect: Restart your computer.  The SSWAP utility will notice the difference in your CONFIG.SYS files; press Enter to restart again.

Fixing a low compression ratio by adding /P=9 to STACKER.COM in CONFIG.SYS isn't enough.  That only compresses files added to your Stacker drive after the change was made.  To re-compress files already on your Stacker drives you need to re-stack each of them.  This is done with the SDEFRAG command in the following format:

 

SDEFRAG d: /GL

 

The d: represents the drive letter of a Stacker drive.  Without it, SDEFRAG works on the current drive.  The /GL switch directs SDEFRAG to change the compression ratio for your Stacker drives.

 

   SDEFRAG's /R switch is used to re-stack a drive, which may help compression in some circumstances.  To specifically change a drive's compression ratio, the /GL switch is used.

 

Type in the SDEFRAG /GL command in your Stacker directory to change the compression for your Stacker drive(s):

 

C:\STACKER> SDEFRAG /GL

 

Above, SDEFRAG will change the compression ratio for the current drive.  After a  few initial scans of the drive and optimization, SDEFRAG's initial screen describes your Stacker drive's current compression ratio and allows you to enter a new value (Fig. 6-6).  I erased the 1.7 on my screen and typed 2.0 into the box to get my Stacker drive up to par.  You should do the same on your system if you feel the Stacker is treating your compression ratio unfairly.  However, don't be too ambitious; the compression ratio is a best-guess thing, and though Stacker will try hard it can't always compress as much as you may want it to.

 

Figure 6-6.  SDEFRAG /GL's screen lets you adjust your Stacker drive's compression.

 

After pressing Enter, SDEFRAG will offer you a screen full of projections about your Stacker drive using the new compression ratio.  Press Enter to accept the new settings, or select one of the other options to change the compression ratio or bail out of the program. If you press Enter, Stacker quickly makes the modifications.  You'll need to restart your PC afterwards.

When your system comes back up again, you can run the REPORT utility to view any improvements in your Stacker drive's compression ratio. On my system, with the /P=9 switch added by the TUNER utility and after running SDEFRAG /GL, my overall compression didn't change much.  This means that Stacker is doing the best job it can with my files, even though it's only a 1.7:1 ratio.  Other tricks worth trying to improve the compression ratio include the following:

 

Avoid putting certain types of files on your Stacker drives  One strategy to take is to keep poor compression candidates off your Stacker drive. Keep a large enough part of your disk uncompressed or, if you're using multiple partitions, keep one of your disk partitions open for GIF, PCX, ARC, and ZIP-like files, as well as program files that don't compress too well.  (Unfortunately, this isn't practical in most cases, since you may not have enough room on your host drive for the files.)

 

Change the Stacker drive's cluster size  You can adjust the cluster size of the Stacker drive through a process known as shrinking the drive, which is covered later in this chapter. (Don't get excited. It won't compress stuff that can't be compressed in the first place.)

 

Upgrade your PC with the Stacker co-processor  Another way to improve compression is to install the Stacker co-processor hardware if you haven't already. Refer to chapter 2 for the details.  You can then re-Stack the drive using the SDEFRAG /R command to take advantage of the new compression.

 

Caching under Stacker

 

Here's a great hint: to immediately increase the speed at which Stacker reads and writes files, install the Stacker co-processor hardware. This is the biggest performance boosting move you can make. Aside from that, you can use a disk cache to improve Stacker's speed, as well as overall disk performance across your system.

There are several popular disk caching programs available, including the SMARTDrive program that comes with DOS and Windows. The rules for using these programs with a Stacker drive are simple: cache the host drive only, not the Stacker drive. After all, because the Stacker drive really is only a file on the host drive, it makes sense to stack only the host drive.

For example, suppose you've stacked drive C. The Stacker drive is C, and the host drive will be given letter D. You should cache only drive D. Using SMARTDrive, you would put the following command into AUTOEXEC.BAT:

 

C:\DOS\SMARTDRV.EXE C- D

 

The C- means not to cache drive C, which is your Stacker drive. The D by itself means to cache drive D, the Stacker drive. (All real disk access takes place on that drive anyway.)

 

   The latest version of SMARTDrive recognizes Stacker drives and will not cache them.  If you have SMARTDrive version 4.0 or later, there is no need to specify a minus after a Stacker drive letter. SMARTDrive has gotten smarter!

 

Some disk caches are SYS files, loaded in CONFIG.SYS (for example, the older version of SMARTDrive). When this is the case, you should load the disk cache in CONFIG.SYS before you run the STACKER.COM device driver. If it must be loaded in AUTOEXEC.BAT, turn off caching for the Stacker drive and cache only the host drive, as was done above with SMARTDRV.EXE.

 

   Another DOS disk cache-type of program is FASTOPEN. Don't use it!  Especially if you already are using a disk caching program, delete FASTOPEN.EXE from your drive!  Do it now, well before the rapture!

 

The reason for not caching the Stacker drive is that Stacker has its own, built-in cache. This already might have been set up for you during installation, either with the /EMS or /M switches.

If Stacker detected any expanded (EMS) memory, then you're using Stacker's cache right now. This can be verified by checking for the /EMS switch located after the command that loads STACKER.COM in your CONFIG.SYS file. Type the following at the command prompt to verify that:

 

C:\> FIND /I "STACKER.COM" C:\CONFIG.SYS

----------C:\CONFIG.SYS

DEVICE=C:\STACKER\STACKER.COM /EMS C:\STACVOL.DSK

 

If you see something like this, then you already are using the EMS cache, a 64K chunk of expanded memory Stacker uses to improve disk speed on your system. As a bonus, the /EMS switch also removes a big chunk of the STACKER.COM program from memory, which will ease your memory management concerns.

 

   If you're using QEMM and Stacker with the /EMS switch, you must add the DBF=2 option to the command that loads QEMM386.SYS in your CONFIG.SYS file. For further information, refer to chapter 4, the section titled ``Using Stacker with QEMM.''

 

When you don't see the /EMS switch you can use the /M switch to specify a cache.  The /M is followed by an equal sign and a value from 1 to 64 representing the size of Stacker's cache in kilobytes.  For example:

 

DEVICE=C:\STACKER\STACKER.COM /M=64 C:\STACVOL.DSK

 

Above, a nice, big, fat 64K cache is setup for Stacker to use. The bigger the cache, the better, with 64K being best. The downside to this is that each kilobyte used for the cache is one less kilobyte of available conventional memory. That hurts.

If you want to make this change, use the DOS Editor, Stacker's beloved ED, or your favorite text editor to make the above modification, inserting the /M=xx into the DEVICE command that loads Stacker. (I'd recommend setting xx equal to 64.) Save the changes to disk, exit your editor, then reset for the changes to take place.

 

   Here's another big tip: if you already are using a disk caching program and don't have any expanded memory, you should set Stacker's /M switch equal to zero: /M=0. This will save on conventional memory as well as shrink the resident size of the Stacker drive driver.

 

Optimizing the Stacker drive

 

The best way to improve a Stacker drive's performance is to optimize it. This also holds true for un-stacked drives. Running a disk optimizer, such as DeFrag, Norton's Speed Disk, PC Tools' Compress, or Mace's UnFrag will speed up disk access by eliminating fragmented files. For Stacker drives, you use the SDEFRAG utility, which does a number of other miraculous things for your Stacker drive in addition to optimization.

 

   You can use SDEFRAG only with Stacker drives. It's not a general-purpose disk optimizer. Also, do not use other disk optimizers on the Stacker drive, use them only on the host drive.

 

Keep in mind that SDEFRAG is not a magic wand you can wave over a Stacker drive to increase performance. I don't recommend using it to optimize your Stacker drive unless over 10% of your files are fragmented. SDEFRAG will alert you to this when it starts. In Fig. 6-3, you see that fragmentation is only 0%. On the screen, SDEFRAG recommends you "exit" out of the program and do nothing.

 

Figure 6-7. SDEFRAG is telling you the drive is okay.

 

Fragmentation will increase on a Stacker drive as you work with larger and larger files. Eventually, those files will be splintered into so many pieces that performance will suffer. (Trust me, you'll know when this happens -- it's nothing subtle.) At that time, you should run SDEFRAG. It will clean up the files on your drive and re-compress some files to improve your overall compression ratio. After that you should run CHECK on the same Stacker drive, then run CHKDSK on the host drive.

If you need to defragment your Stacker drive, start by disabling any disk caching software in your CONFIG.SYS or AUTOEXEC.BAT file. Use a text editor, DOS's EDIT program, or Stacker's ED and place a REM command in front of the caching software. For example, you would change:

 

C:\DOS\SMARTDRV.EXE

 

to read:

 

REM C:\DOS\SMARTDRV.EXE

 

Save the change to CONFIG.SYS or AUTOEXEC.BAT, return to DOS, then reset your computer. Once the cache has been disabled in this way, go ahead and run SDEFRAG. After SDEFRAG is done, reset your computer again.

If defragmentation is a big concern around your computer, then consider adding the following command to your AUTOEXEC.BAT file:

 

SDEFRAG d: /Q

 

The /Q switch directs SDEFRAG to perform a quick optimize of the Stacker drive d:.  SDEFRAG will search out and "glue together" only those files that are fragmented.  This takes less time than running the full SDEFRAG program, and will keep your system tuned up each time you start your computing day.

 

   The SDEFRAG utility also can expand or shrink your Stacker drive. This is covered in the section titled ``Altering your Stacker drive'' later in this chapter.

 

Using disk utilities

 

Stacker is unobtrusive, offering only subtle messages when you start your PC as a clue that it's working. For the majority of your software, Stacker's presence will go unnoticed. For disk utilities, however, a few changes are in order. This is nothing big. Stacker works with all common disk utilities, including everything DOS offers: Undelete, Unformat, the Mirror program, and on and on. Those few exceptions are listed in the sections below.

 

Backing up a Stacker drive

 

Oh, face it, you probably hate to back up as much as I dislike writing about it. No need to preach here. Instead, you probably are wondering how to handle a hard disk backup with a Stacker drive. There are two ways to go.

            First, you can back up a Stacker drive just like any other drive on your system. You can even use programs such as the Norton Backup or PC Tools' Backup. The files are copied from the Stacker drive in an uncompressed format, so don't expect the backup to use any fewer disks. So far, everything is okay.

 

   Both PC Tools' Backup and the Norton Backup use compression technology invented by the same folks who bring you Stacker.

 

Second, you can opt to back up the host drive. This is possible, but rather silly. What would happen is that you'd back up one or two files left on the uncompressed (or host) drive, then one mega-huge STACVOL.DSK file, which is the Stacker disk. That works fine and uses less diskettes than backing up the Stacker drive. The only problem is that, if you ever want to restore one file, there's no way to weed it out of the STACVOL.DSK file. On the other hand, if you back up the Stacker drive as described earlier, restoring one file isn't such a hassle.

I recommend backing up the Stacker drives individually. Then, there's no need to back up the host drive -- save for drive C. Always back up your boot drive, although you can skip backing up the hidden STACVOL.DSK file.

 

Disk optimizers

 

Disk optimizers, such as DeFrag, Norton's Speed Disk, PC Tools' Compress, or Mace's UnFrag, will rearrange files on your hard drive, splicing together their fragmented bits and giving you uninterrupted, contiguously used disk space. This is something that should be done regularly -- but not with your Stacker drive.

To defragment a Stacker drive, use the SDEFRAG utility as described earlier in this chapter. You can continue to use the other defragmentation and disk optimization utilities on non-Stacker drives as you have before.

 

   If you use a disk optimizer other that SDEFRAG on your Stacker drive, run the CHECK utility and CHKDSK -- both with their /F switches -- to clean up any errors.

 

Disk repair and low-level utilities

 

Stacker is friendly to all disk utilities, including those that work on a low-level, such as SpinRite, the Norton Disk Doctor, Disk Technician Advanced, and other state-of-the-art PC disk utilities. The only major warning to heed here is that you should use these low-level utilities on the host drive (after all, the Stacker drive is simply a file on the host drive).

 

   Only run low-level utilities on the host drive--not the Stacker drive.

 

For example, suppose that drive C is your Stacker drive and drive D is the host. In that case, you would use the utility on drive D -- not C. The utility will work just fine on that drive, no sweat.

If you've eliminated the host drive letter (as described in chapter 5), then you'll need to bring it back to run a low-level disk utility. Simply add the STACVOL.DSK filename after the drive letter and sandwich a backslash between them. For example:

 

DEVICE=C:\STACKER\STACKER.COM C:\STACVOL.DSK D:

DEVICE=C:\STACKER\SSWAP.COM C:\STACVOL.DSK

 

These commands mount drive D automatically when the STACKER.COM program is run in CONFIG.SYS. The changes necessary to revive its host drive are:

 

DEVICE=C:\STACKER\STACKER.COM C:\STACVOL.DSK ­D:\STACVOL.DSK

DEVICE=C:\STACKER\SSWAP.COM C:\STACVOL.DSK

DEVICE=C:\STACKER\SSWAP.COM D:\STACVOL.DSK

 

First, the full pathname to the STACVOL.DSK file is specified. Second, the SSWAP utility is run to swap the Stacker drive/host drive letters. Now, the system will have two Stacker drives, C and D, plus two host drives, E and F. You would run the low-level utility only on drives E and F.

When you encounter an error and the error is in the STACVOL.DSK file, take these steps:

 

1.   Quit the disk utility and return to DOS.

 

2.   Remove the STACVOL.DSK file's hidden, system, and read-only file attributes. This is done with the following command:

 

C:\> ATTRIB -H -S -R D:\STACVOL.DSK

 

This command uses DOS's ATTRIB (Attribute) command to peel off the hidden (-H), system (-S), and read-only (-R) attributes of the STACVOL.DSK file. Note that STACVOL.DSK is located on drive D, the host drive. Be sure to specify the proper drive (always the host drive).

 

   You also can use the SATTRIB utility that came with Stacker. It uses the same format as the ATTRIB command in DOS versions 5.0 and later.  Earlier versions of DOS (4.x and before) should use SATTRIB.

 

3.   Run the disk utility on the host drive again (drive D in this example). This will fix any problems.

 

4.   Reset the hidden, system, and read-only file attributes:

 

C:\> ATTRIB +H +S +R D:\STACVOL.DSK

 

Note how plus signs are used instead of minus signs. This replaces the STACVOL.DSK file's hidden (+H), system (+S), and read-only (+R) attributes.

 

5.   Reset your computer: Ctrl-Alt-Del.

 

Other forbidden stuff

 

Here are additional do's and don'ts for your Stacker drive:

 

Don't Format Your Stacker drives  Don't bother using the DOS FORMAT command on a Stacker drive.  This is a fine example of spinning your wheels, since you can't format what is essentially a file on a disk.

 

Don't Format a Host Drive  The host drive, even though it may appear empty according to the DIR command,  contains the STACVOL.xxx file, your Stacker drive.  If you format the host drive, you'll utterly zap your Stacker drive -- even though the two have different drive letters.  My advice: Use the DIR /A:H command on a drive before formatting it.  The /A:H switch detects any hidden files, which includes the STACVOL.xxx file.

 

Don't Use FDISK on a Host Drive  FDISK is DOS's hard disk partitioning software.  If you modify your partitions, you'll zap your hard drives and any Stacker drives' STACVOL.xxx files on those drives.  Note that you cannot use FDISK to modify a Stacker drive.

 

Disk housekeeping

 

Disk housekeeping is a friendly term for what the computer industry calls hard disk management. That's the routine care and use of your PC, all its programs, and the files you create. If you're curious about the subject, you can read my book, Hard Disk Aerobics (TAB book #????), also available from Windcrest.

Stacker's presence has little impact on your regular disk housekeeping (or hard disk management) chores. You still can copy files, delete unneeded ones, organize files into subdirectories, and back up and install new software just as you have before. The only things you need to watch out for are programs that want to place themselves into your CONFIG.SYS, specifically, new device drivers.

 

Adding a new device driver to CONFIG.SYS

 

When you modify the CONFIG.SYS file on drive C, you're modifying a copy of CONFIG.SYS on the Stacker drive. The real CONFIG.SYS is actually on the host drive, which can be drive D, E, or higher, depending on the number of drives in your system. (If your Stacker drive isn't drive C, this isn't an issue.)

Modifying CONFIG.SYS is nothing big. When the SSWAP program is run with its /SYNC+ option, both CONFIG.SYS files on the host and Stacker drive will be compared. If there are any differences, the newer files will be copied over the older files.  If that means CONFIG.SYS must be copied from your Stacker drive to the host drive, you'll be given the chance to reset so those new changes can take affect.  (You must press Enter to make this happen.)

 

   If you use SSWAP's /SYNC switch instead of the /SYNC+ switch, you'll be asked yes or no if you want to update the files and be given the opportunity to select which files you want to use from either the Stacker or host drive.

 

The part you need to look out for is the actual device driver itself. For example, consider that you're adding the ZAP.SYS device driver, which controls a powerful laser you've just attached to your PC. The INSTALL program puts the ZAP.SYS device driver and its associated programs into the C:\ZAP directory. It then modifies CONFIG.SYS, adding the following:

 

DEVICE=C:\ZAP\ZAP.SYS /ON /CRISP=99

 

For that change to take affect, you reset your PC. Upon booting, DOS loads CONFIG.SYS from the host drive and reads it in. The Stacker drive (with all the ZAP files on it) then is started and the drive letters switched. At that time, the SSWAP utility notices your two CONFIG.SYS files are different. The newer file -- the one on the Stacker drive, C -- is then copied to the host drive, D.  You press Enter and your computer resets again.

On the second boot, your CONFIG.SYS file is loaded and DOS encounters the line DEVICE=C:\ZAP\ZAP.SYS etc. However, it looks on the disk and it finds no ZAP directory -- and definitely no ZAP.SYS file.

Normally, this would result in an error:

 

Bad or missing ZAP.SYS

 

Because ZAP.SYS appears before the Stacker drive is created, DOS has no access to it. Prior to version 3 of Stacker, you would have to create a duplicate ZAP directory on the host drive copy ZAP.SYS there as well.  Either that or you could move the ZAP.SYS command after the DEVICE command that starts Stacker or create a ZAP directory on the host drive and copy ZAP.SYS there. But with Stacker version 3, it will search out the missing driver on the Stacker drive and make the duplicate for you automatically.

Okay.  So what's the point if all this is done automatically?  The idea is to keep you aware of what's happening.  Stacker will search out and update the files required to boot CONFIG.SYS.  It makes duplicates and places them into mirrored directories on the host drive.  Even so, you may want to do this before Stacker catches the error.  (Though just being aware of the situation is probably enough.)

Another problem that may arise is with related programs the device driver may use.  Consider the following:

 

DEVICE=C:\ZAP\ZAP.SYS /CONFIG=C:\ZAP\ZAP.DAT

 

Above, the ZAP.SYS device driver has a parameter that mentions a file, ZAP.DAT, also in the C:\ZAP directory.  Though Stacker has its good days, it may not recognize this file and make a duplicate on the host drive.  It's up to you to make that modification.  Further, you may want to place the file reference in the SSWAP.CFG file, located in the root directory of both Stacker drive C and its host drive.  The entry for ZAP.SYS would look something like this:

 

ZAP.SYS     C:\ZAP\ZAP.DAT \\Cool Laser Program

 

Above, SSWAP will compare both ZAP.SYS and ZAP.DAT on the host and Stacker drives.  With the /SYNC+ switch specified, any change in either file will result in both copies being updated.  This is how you can keep your CONFIG.SYS file and its device drivers in a solid state of sanity when you've Stacked your C drive.

 

Organization of the host drive

 

Under Stacker, your host drives are only for those files that must be there. This includes the following:

 

   Device drivers mentioned in CONFIG.SYS before the Stacker drive is created.

 

   The Windows' permanent swap file and other swap files.

 

   The STACVOL.DSK file(s).

 

   COMMAND.COM and other files needed to start your computer (only if drive C is your Stacker drive).  This includes CONFIG.SYS, AUTOEXEC.BAT, SSWAP.CFG and other boot-up files.

 

   Any files that, for some reason, Stacker has refused to place on the Stacker drive.

 

   Special files used for disk recovery, including some of the Stacker utilities.

 

The last category is the only one you should concern yourself with. If anything happens to the Stacker drive, such as a disk crash or virus, then only the host drive will be available. Because of this, you also should maintain a copy of some disk recovery programs on your host drive. Don't put everything there, because space is tight. Just a few important tools, such as Norton's Disk Doctor, SpinRite, Disk Technician Advanced, or PC Tools' DiskFix, are all that you need. Stacker also keeps a few of its own utilities handy to assist in data recovery.

One final word of warning: never erase a STACVOL.xxx file. This removes your Stacker drive and all its data. Detailed instructions for doing this on purpose are presented in the following sections.

 

Review

 

For the most part, dealing with a Stacker drive is identical to working with an un-stacked drive. There are a few minor points you'll have to deal with, which was the subject of this chapter.

Use the CHECK command to check a Stacker drive's performance. That will tell you the amount of space on a Stacker drive, the overall compression ratio, and if any errors exist. If so, then run CHECK /F to fix the errors.

You can check a Stacker drive's performance using CHECK or the SDIR command, but the best tool is the REPORT utility.  REPORT graphically displays the drive's compression ratio.  This can improved upon by using the TUNER utility or the SDEFRAG command with its /GL switch.

Optimizing the Stacker drive is done with the SDEFRAG utility. Do not use a third-party disk optimizer on a Stacker drive.

When backing up a Stacker drive, you can either back up the drive itself or the host drive. I recommend backing up the Stacker drive, because that allows you to restore files individually.

Third-party disk utilities work fine on Stacker drives, although low-level utilities should be run only on the host drive.

Device drivers in CONFIG.SYS need to exist in mirrored directories on both the host and Stacker drive. This is vital if you've stacked drive C.