Media Share 9/MEDIASHARE_09.ISO/misc/dos62up.zip/DBLS.DOC

Text File | 1993-12-14 | 9KB | 188 lines

          DOUBLESPACE RENOVATION

          DoubleSpace is a program that can increase the capacity
          of your hard drive by using disk compression.  It may
          almost double the size of your hard drive by compressing
          files.  Compression programs use a kind of shorthand so
          that repeated data is stored in less space.  Actually, a
          DoubleSpaced compressed drive is a single file on an
          uncompressed drive.  Such files are called Compressed
          Volume Files (CVF).  DoubleSpace is invisible to your
          programs.  You can use DoubleSpace on both hard disks and
          floppy disks. The actual program is called DBLSPACE.
          There was a lot of controversy about DoubleSpace in DOS
          6.0.  Some people had terrible trouble with lost data,
          cross-linked files, etc.

          With DOS 6.2, Microsoft really worked hard to get
          DoubleSpace working perfectly.  They have built in all
          kinds of new protection.

          However, my advice is DON'T INSTALL DOUBLESPACE unless
          you really need more space on your hard drive and are out
          of money.  Hard drive prices have really come down.  A
          bigger hard drive is a better solution than any of the
          hard drive compression programs available on the market.

          Nevertheless, there are some situations where you might
          find DoubleSpace a good solution.  Laptop computer owners
          will find DoubleSpace attractive.  This is because bigger
          hard drives for laptops are still expensive.  For a lot
          more information on DoubleSpace (including some shortcut
          commands) see pages 220 - 231 in LEARNING DOS FOR THE
          COMPLETE NOVICE, 2nd edition.

          DOUBLEGUARD.  With DOS 6.2 Microsoft is using a new
          technology called DoubleGuard for their new DoubleSpace
          compression.  DoubleGuard carefully checks the in-memory
          buffers used by DoubleSpace to hold data.  If it finds an
          error DoubleSpace will pop up an error message.  By
          default, if you install DoubleSpace, DoubleGuard
          protection is activated.  DoubleGuard results in a
          performance decrease of about 2 percent.  This is a small
          price to pay for the extra protection.

          MicroSoft has a provision to turn off DoubleGuard, but
          such action would border on lunacy.  Anyone who is using
          DoubleSpace and turns off DoubleGuard, probably also
          enjoys a good game of Russian Roulette!  If you are using
          DOS 6.2, you can get more information about DoubleGuard
          by typing at the system prompt:

                              help doubleguard <ENTER>

          SURFACE SCAN.  If you install DoubleSpace, DOS 6.2
          automatically does a surface scan of the hard drive.  If
          it finds potential problems it suggests that you run a
          new program called SCANDISK.

          SCANDISK is a marvelous new program that for most
          purposes will replace the CHKDSK and the
          DOUBLESPACE/CHKDSK commands.  However, when you quickly
          want to see how much space is left on a disk, CHKDSK is
          the command to use.  SCANDISK can diagnose and repair
          errors on both uncompressed and DoubleSpaced drives.
          SCANDISK is one of the best new additions to DOS 6.2.
          The old CHKDSK DOS command would not fix cross-linked
          files.  SCANDISK can fix cross-linked files and clusters,
          and lost clusters automatically.  If you are using
          DoubleSpace and sustain damage to a Compressed Volume
          File (CVF), SCANDISK can repair the CVF and often recover
          the data.  SCANDISK also does a "surface analysis" on a
          hard disk.  If SCANDISK finds unreliable sectors when
          doing this surface analysis, it marks them as bad and
          moves the data to reliable sectors on the hard drive.

          To use SCANDISK, change to the drive you want to scan and
          at the system prompt type:

                              scandisk <ENTER>

          If you want to just check your C drive, type:

                              scandisk c: <ENTER>

          If you want to check all your drives you can issue a
          command like this:

                              scandisk /all <ENTER>

          If SCANDISK needs to fix a problem, you have the
          opportunity to create an UNDO floppy disk.  To create an
          UNDO disk, place a blank formatted diskette in drive A or
          drive B and make the appropriate choice at the prompts.
          This UNDO disk can be used to undo any changes that
          SCANDISK may make.

          To use the SCANDISK UNDO feature, place the UNDO disk in
          the A drive, for example, and issue a command like this:

                              scandisk /undo a: <ENTER>

          If you have DOS 6.2 installed you can get more
          information on the SCANDISK command by typing, at the DOS
          prompt:

                              help scandisk <ENTER>


          DOUBLESPACE UNCOMPRESS.  DoubleSpace has a new option
          which allows you to uninstall DoubleSpace.  However, to
          use this option you must have enough disk space on your
          machine.  Many people do not.  This means you have to
          delete files and or directories to make room.  Be sure to
          back up important files before you delete them.


          A VERY IMPORTANT TIP

          IF YOU ARE USING MSBACKUP to backup files, it is
          important to save your setup as a backup setup file.
          Doing so, insures that you are able to restore any of
          your desired backed up files.  If you are not sure how to
          do this, see page 247 of LEARNING DOS FOR THE COMPLETE
          NOVICE, 2nd edition, by Steven Woas, published by
          Celestial Press.

          To uncompress a DoubleSpaced drive you can issue a
          command like so:

                              dblspace /uncompress c: <ENTER>

          The above command tells DOS to uncompress the C drive.
          If you don't have enough room on the hard drive,
          DoubleSpace informs you of the situation and makes
          recommendations.

          LESS MEMORY.  A portion of DoubleSpace resides in the
          High Memory Area (HMA).  They have reduced the "memory
          footprint" so that now it requires 37K (with automounting
          on) or 33K (if you turn automounting off).  Below,
          "automounting" is discussed.

          AUTOMOUNT.  With DOS 6.0 there is a feature that lets you
          compress a floppy diskette.  However, with 6.0 you had to
          mount the silly thing before you could use it!  This, of
          course, was bordering on the ridiculous.  Everybody was
          poking fun at this feature.  See the cartoon on page 235
          in my book, LEARNING DOS FOR THE COMPLETE NOVICE, 2nd
          Edition.

          Obviously, Microsoft got tired of the jokes and have
          implemented an AUTOMOUNT feature with DOS 6.2.  The
          AUTOMOUNT feature is for DoubleSpaced compressed floppy
          disks and other removable media that are compressed with
          DoubleSpace.  By default, DoubleSpace sets the AUTOMOUNT
          feature to on.  You can turn if off and save 4K of
          memory.  AUTOMOUNT is activated only if you are using
          DoubleSpace.  To see how to turn AUTOMOUNT off, at the
          system prompt type:

                              help automount <ENTER>

          BETTER ERROR MESSAGES.  With DOS 6.0, you may receive a
          cryptic error message such as "The CVF is damaged."
          Microsoft gives more information and help with error
          messages in DOS 6.2.  This is a nice improvement.


          DOUBLESPACE "CLEAN START"

          If you are troubleshooting a computer that is running
          DoubleSpace, with DOS 6.2 there is a feature that will
          let you start your computer without DoubleSpace.  To use
          this feature just reboot your computer.  Wait until you
          see on your screen:

          STARTING MS-DOS...

          Then press:
                                   <CTRL> <F5>

          That is, press down the key marked <CTRL> and while still
          holding down that key, press the function key marked
          <F5>.  Then your machine starts without DoubleSpace.