From: cornet@duteca.et.tudelft.nl (Jan-Pieter Cornet)
Newsgroups: comp.os.msdos.misc
Subject: Re: Norton + Superstore/Stacker: OK ??
Date: 10 Apr 92 11:54:29 GMT
Organization: Delft University of Technology, Dept. of Electrical Engineering

heinicke@uwovax.uwo.ca (Allan Heinicke) writes:

>In article <1992Apr09.074443.19039@donau.et.tudelft.nl>, cornet@duteca3.et.tudelft.nl (Jan-Pieter Cornet) writes:
>> heinicke@uwovax.uwo.ca (Allan Heinicke) writes:
>> 
>>>Is it safe to use (for example) Norton Utilities disk
>>>manipulating programs such as Norton Disk Doctor or Calibrate
>>>on a disk that has been compressed with Superstor (which is bundled
>>>with DR-DOS). 
>> 
>> There's no problem in running disk manipulating programs on SuperStor
>> partitions. I'm not using stacker either, but since it works very very
>> similar it should be the same story here.
>> ...........
>> On the other hand, running things like Calibrate (or Compress) or
>> whatever Defragmenting utility, however fast it seems to be, it's
>> useless. Why? Oh sure, it runs fine, and it probably wouldn't....

>I'm not sure all the bases have been covered. I'm interested in things
>like NDD or Calibrate not for use as defragmenters, but as tools to 
>check the surface and if necessary lock out bad sectors or do a low
>level format in a non-destructive way.  

First, there is no "surface" on a SpeedStor/Stacker drive. The clusters
you "see" are the uncompressed images from somewhere on your host
disk, but you never know where. So you can only operate on the surface
of your original drive, which will be filled with some special file
containing the SpeedStor/Stacker image for 99%.

Let's say you do. Now, when you change something about that special
file, even if you only move a bad cluster to somewhere else, and update
the FAT and everything so the file still looks the same to DOS (those
tools do that automatically for you), you still change something about
the physical layout of the special SpeedStor/Stacker file.

Now I know that this, surprizingly, didn't matter for Stacker v1.0, as
it used the information from DOS, but you can bet that for the newer
versions it _does_ matter. I believe (but I'm not sure about this) that
SpeedStor (as supplied by DR-DOS) and Stacker v1.1 and up, use the
physical track/sector method to get to the special file.

In short, when you change anything to that special file, about layout
and such, and you do not explicitly tell it to the SpeedStor or Stacker
program, you'll be sorry. You will very probably loose data.

Unfortunately, the only way (currently) to let the SpeedStor/Stacker
program know you change things, is to use their own utilities to do
the change, which might not meet your demands. I haven't seen anything
documented about the way these utilities work internally, how they
handle their data. When and if they do, 3rd party software will pop up that
allows you to change things, probably.

Until then, you have only one way to "fix" a drive. Do a full backup,
erase everything, fix the bad clusters or what you wanted to fix, and
re-install the SpeedStor/Stacker volume, and then fill it again from
your backup.

Good luck,
-- 
-- Jan-Pieter
cornet@duteca.et.tudelft.nl