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STACKER NOTE                                                   STACKER NOTE
Title: Write-Protected Stacker Drives.
STAC FAX Index #2701 - 02/10/93                         
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Background.

   When file corruption such as a damaged temp file is detected, Stacker will 
   write-protect the drive as a means of safeguarding data.  This forces the 
   user to run Stacker's SCHECK /F (Stacker 2.0) or CHECK /F (Stacker 3.0), 
   to repair logical data structures before anything else can be written to 
   the drive.  Stacker will also write protect a mounted drive if it has not 
   been "padded" to its full size.  The fix for this condition involves the 
   SCREATE program (Stacker 2.0) or the CREATE program (Stacker 3.0) and is 
   discussed in greater detail in section #3.

Procedures.

1.  Fixing Errors with SCHECK /F (Stacker 2.0) or CHECK /F (Stacker 3.0)

    SCHECK and CHECK are similar to the DOS CHKDSK program in that they 
    check for and repairs allocation unit errors.  Unlike CHKDSK which  
    works at the DOS cluster level, SCHECK and CHECK will diagnose and repair 
    at the sector level. Stacker's ability to store on a sector-by-sector 
    basis makes this a necessity.  Because SCHECK and CHECK only repair 
    sector allocation errors, they will recommend using CHKDSK to fix any DOS 
    cluster allocation errors that are detected.  Sometimes they will offer 
    to delete damaged files. They are able to do this even though the drive 
    is write-protected.  If they offer to do this, make a backup copy of the 
    file and let SCHECK or CHECK delete it.  After SCHECK or CHECK has made 
    repairs, the write protection may then be removed by rebooting or by 
    unmounting then re-mounting the drive.

2.  Forcing SCHECK or CHECK to remove the write protection.

    DOS errors can be repaired by CHKDSK or another disk repair utility such 
    as Norton Disk Doctor or PCTOOLS Diskfix.  Because SCHECK and CHECK will 
    not repair all DOS errors, it may be necessary to force them to remove 
    the write protection before one of these utilities may be used.  This 
    should ONLY be done AFTER SCHECK /F (Stacker 2.0) or CHECK /F 
    (Stacker 3.0) has repaired any Stacker errors.  Remove the write 
    protection by typing:     
    
    Stacker 2.0  -  SCHECK /=W   D:    where D: is the write-protected drive.  
    Stacker 3.0  -  CHECK  /=W   D:    where D: is the write-protected drive.
    
    NOTE: DO NOT use this option if the Stacker drive has been mounted as 
    (SIZE MISMATCH) (Write-Protected).  See section #3.

3.  Repairing a (Size-Mismatched), (Write-Protected) Drive.

    Stacking a drive is a three step process.  First, construction of the 
    Stacker drive companion file (STACVOL.DSK) begins as compressed files are 
    copied into it.  After all the files have been added, Norton Speedisk is 
    run to defragment this file and optimize the host drive.  The last step 
    is to "pad" the file (add the free space).  If the process halts for some 
    reason, such as Speedisk discovering a bad sector or someone tripping 
    over the power cord, the Stacvol file will be undersized.  Upon reboot, 
    as the drive is mounted, the message (Size Mismatched)  (Write Protected) 
    will be displayed.  In order to continue where Speedisk left off and pad 
    the file, it is necessary to use the Screate program (Stacker 2.0) or the
    CREATE program (Stacker 3.0) as follows:  
    
    NOTE: Insert the Stacker program diskette and issue these commands from  
          the floppy drive prompt. If you are using the 5.25" Stacker 2.0 
          disk set, use the Program Disk (Disk #1). If you are using Stacker
          3.0, use disk #2 of the 3.5" or 5.25" set.
        
        1. Unmount the Stacker drive by typing:  Stacker -C:  
           C: is the letter of the drive you wish to unmount.   
        
        2. Run: 
           Stacker 2.0 -  SCREATE D: /P     
           Stacker 3.0 -  CREATE  D: /P
           Where D: is the letter of the host drive containing 
           the Stacvol file.  
        
        
        3. After receiving the message  "Volume Created Successfully" , 
           reboot to mount the drive.

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Copyright 1993, Stac Electronics