Chip 1997 March/CHIP Mart 1997.iso/prg/DOSLONG/DOSLFNBK.TXT

Text File | 1996-04-13 | 27KB | 553 lines

DOSLFNBK v 1.2 - Backs up/restores Win95 long filenames in DOS

Copyright (c) 1995,1996 D.J. Murdoch.

0. Contents of this file

   1. Syntax
   2. Description
   3. Details
   4. Memory Limitations
   5. Safety
   6. Recovery from Total Disk Failure
   7. License
   8. Release History
   9. Acknowledgments

1. Syntax:

      DOSLFNBK drive:directory [options]

        will back up all the long filename records in the named
        directory and subdirectories of it to a file called
        BACKUP.LFN.

      Options:
        /f filename  Back up to this file instead (default .LFN
                     extension)
        /force       Force DOSLFNBK to go ahead without asking questions,
                     even when it may be unsafe
        /nr          No recursive:  don't do subdirectories
        /nt          Don't restore times from LFN backup
        /p           Prompt before each filename restore (ignored
                     during saves)
        /r           Restore from existing backup
        /s directory Skip directory
        /v           Give running status report
        /d filename  Write a detailed debugging log to filename

      Examples:

        For recovery from a total disk failure, see section 6 below.

        To back up every long filename on the disk into BACKUP.LFN:

           doslfnbk c:\

        To restore just the Windows directory and subdirectories:

           lock c:
           doslfnbk c:\windows /r
           unlock c:

        To restore just the root directory, but no subdirectories:

           lock c:
           doslfnbk c:\ /r /nr
           unlock c:

        To backup everything except the MS Internet Explorer cache and
        history directories:

   lock c:
   doslfnbk c:\ /s \progra~1\micros~1\cache /s \progra~1\micros~1\history

        The following is not allowed; you need a full path:

           doslfnbk .  <---- Error!

        To restore the "Program Files" directory name and its
        subdirectories, you need two runs:

           lock c:
           doslfnbk c:\PROGRA~1 /r
           doslfnbk c:\ /r /p /nr
           unlock c:

        On the second run, you'll be prompted for each name to restore;
        just say yes when you see "Program Files".

2. Description:

        Microsoft's Windows 95 introduces long filenames (LFNs), and
        they are mostly compatible with old software.  However, there
        are some problems.  Old backup programs don't recognize LFNs, so
        they don't get properly backed up.  Worse, the Win95 backup
        program doesn't support a lot of common backup hardware (e.g.
        Colorado Memory Systems tape drives using accelerator cards) and
        won't run in DOS mode, so recovery from a catastrophic disk
        failure can be really difficult.

        To address this problem, Microsoft put a program called LFNBK on
        the Win95 CD ROM to back up your LFNs.  However, it's very
        inconvenient to use.  It requires changes to your Control Panel
        settings before and after use, and it works by stripping all the
        LFNs off your disk --- so you need to restore them again after
        you've done your backup to tape.  It will only run after Win95
        has booted, so again you've got big problems after a
        catastrophic disk failure.  If you've got a program that is
        completely incompatible with LFNs then you might want to use
        LFNBK, but for routine system backups it's too much of a pain.

        I wrote DOSLFNBK to address these problems.  It runs in any
        version of DOS that can see your disk, and can both backup and
        restore your files there.  During backup, it makes no changes to
        the names, so you can routinely run it just before a tape backup
        and not have to undo the damage afterwards.  It also allows
        partial backups and partial restores; I'm pretty sure LFNBK is
        an all-or-nothing affair.

        The downside of DOSLFNBK is that it has to work on the disk
        below the file system level.  This means that if other programs
        are running simultaneously, it can get confused, and may cause
        errors in the backup or even errors on the disk itself.  I
        recommend running it only in a single-tasking DOS session,
        unless you're quite sure no other program is writing to the
        disk.

3. Details:

        Contents of this section:
          - what DOSLFNBK does
          - how to specify which directory to back up
          - existing long filenames
          - date information
          - changed files
          - file attributes
          - the /v verbose option and the /d debug option
          - running in Windows
          - the /force option to ignore warnings
          - the /s option to skip directories
          - large directories
          - the LOCK and UNLOCK commands
          - DOSLFNBK, disk defragmenters and directory sort utilities
          - DOSLFNBK and XCOPY
          - exit codes

        When doing a backup, DOSLFNBK reads the directories on the disk
        and writes copies of all of the LFN records to the binary
        BACKUP.LFN file (or whatever file you specify with /f).  If you
        use the /nr option, it will work only on the specified
        directory; otherwise, it saves those entries as well as
        everything in any subdirectory below it.

        You *must* give the drive letter and a full path to the
        directory to back up; relative directory specifications are not
        supported. Note that the directory name itself won't be backed
        up or restored; only the files and subdirectories within it.
        There is no way to specify a subset of the files; you have to
        use the /p prompting option if you want this.

        The original drive letter is not stored in BACKUP.LFN, so you
        can use DOSLFNBK to save the long filenames on one drive, use a
        DOS utility to move them to another drive, and then restore the
        filenames there.

        DOSLFNBK will normally not overwrite an existing LFN with a
        different one; you should rename the file to its 8.3 alias
        before running if you want to restore an old name, or run with
        the /p option for individual prompting.

        Normally, DOSLFNBK will restore the backed up date information,
        since older DOS versions and DOS utilities probably don't save
        this properly.  You can override this behaviour by using the /nt
        switch.

        If during a restore, DOSLFNBK detects that the file size has
        changed, you'll be prompted as to whether you want to restore
        the LFN or not.  If you choose to restore it, the date
        information will *not* be restored, as it is probably incorrect.

        During a restore, the file attributes of the file on the disk
        will be kept.

        To show you the progress of a run, DOSLFNBK prints a dot for
        about every 10 directories examined or (in /v mode) prints the
        directory and file names.  If it stops printing for more than a
        few seconds, something is probably wrong.  Try running again
        with the /d debug log option, and if it stops again, please
        email me ([e-mail]) a copy of your log, along
        with a description of your system.  I'm very interested in
        making DOSLFNBK as bug-free as possible.

        You'll get a warning if you run it in Windows mode, since other
        programs might change the directories while DOSLFNBK is running
        and cause it to store and/or restore garbage.

        The /force option tells DOSLFNBK to go ahead without stopping
        for this warning, or several others (e.g. overwriting the backup
        file).  Use it in a batch file only when you're sure you always
        want it to go ahead.

        The /s option tells DOSLFNBK to skip the back up or restore of a
        particular directory.  This is meant as a workaround for the
        memory limitations in DOSLFNBK that are described in section 4
        below.  You can use /s as often as necessary to skip multiple
        directories--the only limit is the command line length.  Note
        that the directory name must be specified using the short
        aliases, e.g. "\PROGRA~1" instead of "\Program files".  Relative
        directory paths using "." and ".." are not supported.

        When restoring a directory, DOSLFNBK takes a very conservative
        and careful approach so that it is very likely that you can
        recover from a disaster like a power failure in mid-restore.
        Unfortunately, the method I chose to do this is very slow at
        increasing the size of a directory.  On a large directory, it
        make take several minutes of apparent disk thrashing to get the
        directory up to the required size, and you may think DOSLFNBK
        has crashed, and so reboot your system.  A sign that things were
        really working is that it will have left behind a large number
        of 0 length files with names like 00000123.$$$. If this happens,
        delete those files and try again, or use the /S option to skip
        that directory.  The next version of DOSLFNBK will use a much
        more efficient method of growing the directory.

        During a restore in Win95 MSDOS mode, you should use the DOS
        command LOCK to give DOSLFNBK access to the disk at a low level.
        LOCK is a new built-in MSDOS 7.0 command.  In earlier versions
        of DOS, there is no LOCK.  LOCK will work in a DOS window only
        on a drive with no open files; this means it is impossible to do
        a restore to the drive where Windows files are stored while
        Windows is running.  However, it should be possible and safe to
        restore to other drives if you can successfully LOCK them.
        After DOSLFNBK is done, run UNLOCK to release the drive so that
        other programs can use it.

        You may be tempted to use an older DOS-based disk defragger or
        directory sort utility that doesn't understand long filenames,
        and then use DOSLFNBK to restore the long filenames.  DON'T DO
        THIS! It is extremely likely to cause errors to your directory
        structure which can't be repaired except by hours and hours of
        work.  The problem is that these programs usually leave a few
        files with wrong but apparently correct long filenames.  You'll
        find that 99 percent of your disk is restored, but some small
        number of files are not.  It is extremely difficult and time
        consuming to find and repair these files.  If you want to use
        these DOS-based programs, you should remove all long filenames
        first (e.g. using LFNBK, or by restoring from tape in DOS).  A
        better solution is to use Win95 compatible versions of these
        utilities.  (Win95 comes with a defragger, and there are shareware
        directory sort utilities available, including mine,
        available as ftp://garbo.uwasa.fi/pc/dirutil/lfnsrt10.zip.)

        I have received several messages from people who have tried to
        use XCOPY and DOSLFNBK to back up their disk to a network drive
        or elsewhere, and then found on restore that Win95 won't boot
        properly.  I don't know what is going wrong in these situations,
        but as far as I can tell it's either a bug in XCOPY, or people
        aren't using the right combination of options when they run it.
        If someone has the time to figure out exactly what is going
        wrong, I'd appreciate being told.  In the meantime I don't
        recommend using XCOPY for backups.

        When a run is successful, DOSLFNBK exits with ERRORLEVEL 0.
        When something goes wrong, it prints an error message and exits
        with a higher errorlevel. The currently defined error levels
        are:

         99 = Syntax error
         98 = Error initializing disk
         97 = Error reading disk
         96 = Error writing disk
         95 = Error in directory on disk
         94 = Error setting up directory
         93 = Error opening backup
         92 = Error reading backup
         91 = Error writing backup
         90 = Error closing backup
         89 = Memory error
         88 = Multitasker running
         87 = Backup file exists
         86 = Debug log problem

4. Memory Limitations:

        When running, DOSLFNBK keeps copies of several directories in
        memory at once.  It is written as a real mode DOS program and
        keeps all of this data in the low 640K of memory.  This means
        that in a typical DOS session with 500K of memory available,
        DOSLFNBK will run out of memory when about 15,000 directory
        entries are in memory.  On a restore, up to 3 copies of each
        directory entry may be in memory at once, limiting DOSLFNBK to
        disks with fewer than 5000 directory entries in any branch of
        the directory tree.  (The total number of files on the disk
        doesn't matter; what matters is the number of entries in a
        directory, its parent, grandparent etc., back to the root.)

        When I wrote DOSLFNBK, I thought disks approaching this limit
        were very unusual. However, it *is* possible to have such a disk,
        and here's how to find out if you do:

        Run your backup with the /V verbose option.  At the end, it
        will print a message something like

           Used 255K; restore will require about 264K in DOS session.

        If the amount of memory estimated for the restore is more than
        you have available (as reported by the DOS MEM command), you
        might have problems.  You might not; the number reported is
        usually an overestimate.

        If it ever turns out that you do run out of memory during a
        restore, you can still restore the LFNs by breaking up the
        restore operation into several steps, restoring different parts
        of your subdirectory tree separately.  In the worst case (more
        than 5000 entries in a single subdirectory), you may have to
        temporarily move files out of the directory and restore the LFNs
        a few thousand (!!) at a time.

        Since the original release, it has become clear that there are
        some common situations leading to very large directories. The
        Microsoft Plus! package includes one, and WWW browsers often
        create them while maintaining caches or history lists.
        Unfortunately, the current version of DOSLFNBK doesn't handle
        these very well; in some cases it will crash.  I have added the
        /s option to allow you to skip particular directories during the
        backup or restore operation.  A better solution that allows all
        directories to be backed up is in the works; it may be available
        by June, 1996.

5. Safety:

        DOSLFNBK works with your disk at a level below the file system,
        so if things go wrong during an LFN restore, it's conceivable
        that you could lose whole files or directories.  I've tried to
        make it as safe as I can, but you should follow some simple
        precautions:

          - If you aren't sure of the integrity of your file system, run
          Scandisk before DOSLFNBK and get it to fix any errors.  In
          particular, if you've run other low level software (e.g. a
          defragger or a directory sorter) that may have messed up the
          LFNs, run Scandisk first.  Better still:  don't use that old
          defragger/directory sorter, because Scandisk may not be able
          to repair all the damage it does.

          - If you choose to run in Windows despite the warning about
          the multitasker, then definitely don't make changes to files
          in the directories where DOSLFNBK is currently restoring LFNs.
          You're *very* likely to lose your new work.

          - Don't turn off or reboot your PC in the middle of a DOSLFNBK
          run.  If there's a power failure or (horrors!) a bug in
          DOSLFNBK forces you to reboot, then Scandisk should be able to
          repair much of the damage.  You may lose some filenames, but
          Scandisk should be able to recover the files themselves.

          - If you hit Ctrl-Break or Ctrl-C during a DOSLFNBK restore,
          it shouldn't do any damage other than giving you only a
          partial restore of your LFNs --- but this is *not* a
          well-tested feature, and there may be conditions under which
          you'll suffer worse damage.  Again, Scandisk should be able to
          repair most of it.

          - DOSLFNBK was written for version 4.00.950 of Windows 95 (the
          August 1995 release).  It hasn't been tested on the earlier
          beta test versions, or any versions later than the January 96
          fix pack (version 4.00.950a). If the VFAT file structure isn't
          what DOSLFNBK is written for, it could do some real damage.

          - This is the second release of DOSLFNBK to the public.  There
          may still be special conditions on your system that it doesn't
          handle.  If you can, try it out when you've got a good second
          backup to make sure it works.  If it doesn't, *please* send me
          details, and I'll attempt to fix it.

6. Recovery from total disk failure:

        If your boot disk fails, or you decide to repartition it, then
        you may need to do a full restore from a backup tape.
        Unfortunately, the Win95 backup program provides *no way* to do
        this without re-installing Win95 from the original disks or CD
        ROM.  From reports I've heard, the same is true of the
        just-released Win95 version of Colorado Memory System's backup
        program and some other commercial backup programs.

        However, if you have a reliable DOS-based backup program,
        DOSLFNBK will let you do a complete restore from a backup.  I've
        only had to do this once, so these instructions aren't
        guaranteed to cover everything for every system, but they worked
        on mine.

        ADVANCE PREPARATIONS:

        Before your disk fails (i.e. right now! :-), you need to prepare
        the following:

          1. A Win95 startup disk.  If you didn't create one when you
          installed Win95, start the Add/Remove Programs option in
          Control Panel, and click the Startup Disk tab. Then click the
          Create Disk button, and follow the instructions on-screen.

          2. A copy of your DOS-based backup/restore program on a floppy
          disk.  It may require EMS memory; if so, you should put
          HIMEM.SYS and EMM386.EXE on your startup disk, and load them
          via CONFIG.SYS.

          3. If you use Drivespace disk compression, then you should also
          make sure that the MINI.CAB file from the installation disks
          or the CD ROM is in your Windows directory on the hard disk.

          4. A full backup of your disk(s).  Just before creating this,
          run DOSLFNBK to save all of your long filenames.  You'll need
          to create one backup file for each disk.  It's fine to leave
          this on the hard disk so that it ends up on the backup; you
          don't need to have it on floppy disk.

        WHEN YOUR DISK FAILS:

        Depending on the reason for your disk failure, you may be able
        to skip some of the early steps here.  Read them over, and
        figure out where to start.  If you have to, you can start again,
        so the only thing you lose by starting too far down is time.

          1. Make any necessary repairs to your hardware.

          2. Boot from your Startup disk, and use FDISK to partition
          your disk.  Use "FORMAT c: /s" to reformat the disk and
          transfer the system files to it.

          3. (Optional) Transfer your tape backup software to your hard
          disk.

          4. If you're not planning to use Drivespace, you can skip down
          to step 8.

          5. If you want to compress your drive, you need to restore
          enough of Win95 to run Drivespace.  Don't restore the whole
          disk; you might not have room for it.  For most people,
          restoring the files in the root directory and the files in the
          Windows directory should be enough.  If you have any essential
          drivers in other directories, you'll need to restore them too.
          Finally, you should restore DOSLFNBK and the data file(s)
          containing the backed up long filenames.

          IMPORTANT:  You should not overwrite IO.SYS, but you *should*
          overwrite MSDOS.SYS.  It is a hidden read-only file in your
          root directory.  A good way is to erase MSDOS.SYS before
          starting the restore (use ATTRIB from the Startup disk to
          remove the System, Hidden, Read-only attributes), and then
          telling your restore program not to overwrite existing files.

          Restore all those files now.

          6. Restore the long filenames by running

             LOCK C:
             DOSLFNBK c:\ /R /V /F backupfilename

          The LOCK command is only necessary when using the Win95
          startup disk.  Don't use it when running under earlier
          versions of DOS.

          7. Remove the Startup disk, and reboot your system.  You may
          get some errors about missing drivers (e.g. no sound card
          drivers), but things should basically work.  Run DriveSpace to
          compress your drives the way you want.

          8. Reboot your system in DOS mode or from the Startup disk.

          9. Restore all rest of the files on all of your disks from the
          backup now.  See the "IMPORTANT" note in step 5 about
          MSDOS.SYS and IO.SYS.

          10. Restore all the rest of your long filenames by running

             LOCK C:
             DOSLFNBK c:\ /R /V /F backupfilename

          and if you've also got a D: partition,

             LOCK D:
             DOSLFNBK d:\ /R /V /F backupfilename

          You may get messages about some long filenames already
          existing from your first restore; don't worry about those.

          11. Some restore programs set the archive bit on all restored
          files; you might want to turn it off (since you've still got
          those files backed up) at this point.

        Reboot your system, and things should be back as they were when
        you did your backup!

7. License:

        DOSLFNBK is *not* public domain software, but you may use it at
        no charge.  You may distribute unmodified copies of the complete
        DOSLFNBK package, provided your total charge is no more than $1.
        The total cost of a compilation (e.g. a CD ROM) including
        DOSLFNBK must be no more than $1 per package in the compilation.

        DOSLFNBK was written in Borland Pascal 7.01, using the excellent
        Object Professional library from TurboPower Software.  You can
        obtain the source code (including an object-oriented low-level
        disk access unit and a huge memory support unit, but not Opro)
        by sending a cheque or money order for $50 (in Canadian or US
        dollars, or the UKP equivalent of $50US) to:

         Duncan Murdoch
         337 Willingdon Ave.
         Kingston, Ontario, Canada.
         K7L 4J3

        You can also order source code from the Public (software) Library
        (PsL) using MC, Visa, AmEx, or Discover card:
         - by calling 800-242-4775 (US only)
         - by calling 713-524-6394
         - by faxing your order to 713-524-6398
         - by sending your order by Compuserve to 71355,470.
         - by sending your order by Internet to [e-mail]
        PsL only accepts payment in US dollars.  Please give PsL your
        name exactly as it appears on the card, and tell them your
        card's expiry date.  DOSLFNBK is PsL product #14247.

        The PsL numbers are for ordering only.  I *cannot* be reached at
        the PsL numbers.  To contact me for information about dealer
        pricing, volume discounts, site licensing, the status of
        shipment of the product, the latest version number or for
        technical information write to me at the address above or at
        the email address below.  I'd especially like to hear bug
        reports and suggestions for improvements.

         Internet:   [e-mail]

8. Release history:

       0.0 - first beta test version
       0.1 - kept file attributes of existing file during restore.
       0.2 - made messages more informative; fixed bug in handling
             erased file entries; added check of overwrite of backup
             file; changed default name of backup file to BACKUP.LFN and
             made LFN the default backup extension; added /P option.
       0.3 - fixed memory leak that caused run-time error 203 on large
             restore
       0.4 - added check for successful write of backup file, added
             /force option.
       0.5 - added report of memory use, /d option, many debugging messages
       0.6 - cleaned up messages and debug log, removed disk size
             restriction, added progress dots for non-verbose runs.
       1.0 - first public release --- same as 0.6
       1.1 - unauthorized release
       1.2 - documentation changes and addition of /s option

9. Acknowledgments

        DOSLFNBK was written based on the information in Robert Hummel's
        article on Win95 long filenames in the June/July 1995 issue of
        PC Techniques Magazine.  Thanks are due to the beta testers, who
        suggested many improvements, and several of whom were put to
        considerable inconvenience by early versions that messed up
        their disks.  M. Guffey made a lot of useful suggestions for
        improvements to the documentation.