

NOVELL TECHNICAL INFORMATION DOCUMENT

TITLE:  TROUBLESHOOTING SUPERSTOR
DOCUMENT ID:  TID800022
DOCUMENT REVISION:  A
DATE:  15AUG94
ALERT STATUS:  Yellow
README FOR:  NA

NOVELL PRODUCT and VERSION:
DR DOS 6.0

ABSTRACT:
N/A

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THE ORIGIN OF THIS INFORMATION MAY BE INTERNAL OR EXTERNAL TO NOVELL.  NOVELL 
MAKES EVERY EFFORT WITHIN ITS MEANS TO VERIFY THIS INFORMATION.  HOWEVER, THE 
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MAKES NO EXPLICIT OR IMPLIED CLAIMS TO THE VALIDITY OF THIS INFORMATION.
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ISSUE

SYMPTOM:  TROUBLESHOOTING SUPERSTOR

ISSUE/PROBLEM:   Most disk utilities, other than those included with DR DOS 
6.0, will not be able to properly define the internal structure of a 
SuperStor drive. 

SOLUTION:  It is recommended that utilities that access internal drive
information NOT be used on a SuperStor drive.    

DISKOPT

DISKOPT is the DR DOS 6.0 disk optimization utility recommended for
optimization of a SuperStor drive.  DISKOPT is able to properly analyze the 
internal allocation tables of a SuperStor drive by letting the SuperStor 
driver act as an interpreter to the drive.

CHKDSK

CHKDSK is another DOS utility which allows the analysis of a drive. CHKDSK 
may be used to verify the integrity of a SuperStor drive.   It can also be 
used to fix lost clusters occuring on a SuperStor drive or on any other drive.
However, as noted below, CHKDSK may not always accurately report available 
space on a SuperStor drive.

*REPORTED STATISTICS

The statistics reported by various DR DOS utilities and third party utilities 
will vary with respect to space available on a SuperStor drive.  Each of the 
utilities interprets the SuperStor internal tables differently.


CHKDSK/THIRD PARTY UTILITIES

CHKDSK will not normally portray the proper amount of available space on a 
SuperStor disk.  This is because CHKDSK bases all of its information on a 
perfectly formatted hard disk partition.  That is to say, CHKDSK will always 
assume the optimum result. In the case of SuperStor, CHKDSK will assume that 
a perfect 2:1 compression ratio is always maintained.  However, as SuperStor 
is used, its compression ratio will vary due to the differing compression 
ratios of the individual files put on the drive.  Some files will have better 
than 2:1 compression ratios and some will have less than 2:1.  Therefore, 
actual statistics will vary between CHKDSK and third party utilities as they 
are using this perfect 2:1 compression ratio to calculate free space.      


DIR/XDIR/SUPERSTOR STATISTICS

DIR, XDIR, and the SuperStor Statistics option should be used to properly 
determine the current SuperStor free space.  All three of these options have 
adjustments built into them to account for the different compression ratios 
of each individual file kept on the SuperStor drive.  


*RESERVED UNITS

While performing a CHKDSK on a SuperStor partition, a message reporting: XXXX 
Bytes in SuperStor Reserved Units may be displayed.  There may also be a large
reduction in the amount of disk space free on their SuperStor partition.

SuperStor reserved units are entries in the SSTOR allocation table that are 
marked as unusable due to the storage of uncompressable data on the SuperStor 
partition.  Table entries refer to SuperStor's own internal allocation table. 
Uncompressable data is defined as that which cannot be compressed further by 
using SuperStor (Arc'd, Zip, Gif files, Exepacked files, etc.)  The following 
is an explanation of how reserved units are applied:

                Actual Drive            SuperStored (compressed) Drive



                50 MB                   100 MB (2:1 compression ratio)

20% of drive    10 MB Zipped File                10 MB
(uncompressed)

                -----------------      ------------------------------

Space           40 MB Free Space                 90 MB Free
(reported)

SuperStor                                        10 MB
Reserved Units

                                               
                                       ------------------------------
                                                 80 MB                          
                      80 MB Free
Space (actual)


The example above shows a 50 MB hard disk has been compressed with SuperStor 
to create a 100 MB SuperStor partition.  There is a 10 MB uncompressed zip 
file on this partition.  Prior to using SuperStor the zipped file would have 
taken up approximately 20% of the 50 MB drive. (i.e. 10MB zipped file / 50 MB 
of total space = .20 or 20%.)  The same applies after a SuperStor volume is 
created.  However, in order to maintain the 20% occupancy of the zipped file, 
10 MB of Reserved Units are needed. i.e. 10MB zipped file + 10 MB Reserved 
Units = 20 MB compressed.  20 MB compressed / 100 total space (after 
SuperStor) = .20 or 20%.

Since the 10 MB zipped file cannot be compressed it is stored on the 
SuperStor hard disk partition in an uncompressed format.  It is actually 
using 10 physical MB of disk space (as if SuperStor had never been used).  
Since the zipped file was not compressed, it has essentially a 1:1 compression
ratio (Remember, SSTOR cannot further compress a file which already is 
compressed).  Using a CHKDSK /F may clear the Reserved Units message shown 
previously by CHKDSK, but will not free up the disk space.  In fact, the 
message will usually reappear after a few reads or writes have been made to 
the SuperStor partition.

Reserved Units will generally appear when your drive is 90% full or greater.  
If Reserved Units have appeared due to the storage of uncompressable data on 
a SuperStor drive, move the uncompressable data to a uncompressed drive. Then,
free the SuperStor Reserved Units by performing a CHKDSK /F on the SuperStor 
drive.


*BACKING UP A SUPERSTOR DRIVE

DIRECT MEMORY ACCESS- The software available today offers a variety  of 
backup and restore options. Many of these backup options allow Direct Memory 
Access (DMA) backups which are sometimes called direct access or fast backups.
These types of backups do not use conventional DOS routines. This method does 
not allow the SuperStor driver (SSTORDRV.SYS) to act as a translator during 
the backup process. Use of a DMA backup option on a SuperStor compressed 
partition can result in a error message from the backup program such as 
"Drive not ready".


IMAGE BACKUP (OR MIRROR BACKUP)

Image backup options allow a user to take an entire physical backup of a disk 
from beginning to ending cylinder.  Think of it a as a photograph that 
duplicates the entire contents of a disk including all system, hidden and 
read-only files along with FATs and directories. These backups are not 
recommended for a SuperStor drive as the prospective restore disk may not 
properly accept the backup. The restore drive MUST have the exact same 
parameters as the backup drive (drive size, total sectors, sectors per track, 
etc.).


FILE-BY-FILE BACKUP

File-by-file backups are the most reliable backup method for use on a 
SuperStor compressed partition. This backup option allows intervention of the 
SuperStor driver so that files on the backup are uncompressed and can be 
restored to either a compressed or a non-compressed drive.

                HELPFUL TROUBLESHOOTING TIPS


*IF SUPERSTOR WILL NOT COMPRESS A NON-BOOTABLE PARTITION.

If SuperStor detects any files marked with the S for System attribute,
SuperStor will not install.  Use XDIR on the prospective drive to locate files
with the System attribute active.  Then, remove these files, or their System 
attribute so that SuperStor will execute.

*SUPERSTOR HAS BEEN USED ON A BOOT DRIVE WHICH WAS PARTITIONED WITH A 3RD 
PARTY DISK PARTITIONING SCHEME.  NOW, THE DRIVE LETTERS ARE OUT OF SEQUENCE.

This is because the partitioning driver (Diskmanager, Speedstor) is loading 
after the SuperStor (disk compression) drivers have loaded.  Place the 
partitioning driver before the SuperStor drivers in the correct configuration 
file.   

*A THIRD PARTY DISK PARTITIONING SCHEME HAD BEEN USED ON A DRIVE IN WHICH 
SUPERSTOR HAS NOW BEEN USED TO COMPRESS DATA.  ALL PRECAUTIONS TO MOVE THE 
PARTITIONING DRIVER TO ITS CORRECT POSITION HAVE BEEN TAKEN.  HOWEVER, 
SEVERAL ADDITIONAL "PHANTOM" DRIVE LETTER NOW APPEAR WHICH DID NOT APPEAR 
PRIOR TO SUPERSTOR.

Check to see if the disk partitioning scheme has a driver loading in another 
configuration file as well.  Make sure that this driver is only loading once 
in the appropriate location. 


*AVAILABLE SPACE ON THE SUPERSTOR DRIVE IS QUICKLY REDUCED

First, scan the current compression ratios of the various files on the
SuperStor drive.  The XDIR command will display the compression ratios of each
individual file.  Once you have determined which files have poor compression 
ratios (1.3:1 or less), consider moving them to an uncompressed portion of 
the drive to improve the performance of SuperStor.

Second, perform a CHKDSK on the SuperStor drive to see if there are any bytes 
used by SuperStor Reserved Units.  If so, check for and remove any files which
may be uncompressable (those which have a approximately a 1:1 compression 
ratio).  The SuperStor Reserved Units may be freed up by performing a CHKDSK 
/F.  However, the Reserved Units message in CHKDSK may reappear if 
uncompressable data remains on the SuperStor drive.


ADDITONAL REFERENCES:    DR DOS 6.0 OPTIMIZATION AND CONFIGURATION TIPS GUIDE,
DR DOS 6.0 USER GUIDE

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