(This open letter was written by Ontrack Computer Systems, and is 
posted here at the Seagate Tech Support BBS as a courtesy to users 
of the Disk Manager software program)

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ONTRACK
Computer Systems, Inc.


To   :   Windows 3.0 and Disk Manager users
From :   Ontrack Computer Systems
Re   :   Windows 3.0 and Disk Manager

Ontrack Computer Systems is very concerned about reports of data 
corruption on systems which are using MicroSoft Windows 3.0.  We 
are devoting a great deal of time and effort to track down this 
reported problem, but are unable to produce even one byte of 
corrupted data on any of our computers running Windows 3.0.  We 
have determined the following to be true and verifiable:

1.  If Windows 3.0 is used on a 386 computer which has a hard drive 
with more than 1024 cylinderas and our DMDRVR.BIN is being used to 
allow DOS (and of course Windows) to access that portion of the 
disk, then the "[386enh]" section of the SYSTEM.INI file in Windows 
must contain the following line:

    VIRTUALHDIRQ=OFF

See pages 528-9 in the index of the Windows Users Guide for examples 
on how to modify SYSTEM.INI.

NOTE:   Many ESDI drives exceed the 1024 cylinder barrier but due to 
a translating controller card, appear to the operating system to 
have fewer than 1024 cylinders.  Such a drive is not considered to 
have more than 1024 cylinders and does not fall into the category 
described above.  This is because our SWBIOS.COM utility is not 
required to set up the drive and the DMDRVR.BIN will also not 
utilize that portion of the driver.

2.  The Swapfile program, which is used to set up a permanent swap 
file on the disk, checks for ANY partitioning device driver 
including the DMDRVR.BIN in the CONFIG.SYS file and will not run if 
it exists.  The swap files are hard-coded to use a 512 byte sector 
and in DOS versions earlier than 4.0, Disk Manager increased the 
logical sector size to allow access to partitions greater than 32 
megabytes.  Since this is the case, a permanent swap file cannot be 
used on a disk using the DMDRVR.BIN device driver though temporary 
swap files will work just fine.

Using a temporary swap file instead of a permanent one should not 
degrade performance on a disk that has an optimization utility run 
on a regular basis.

Running such a utility is a good idea anyway for general system 
performance as well as increasing the possibility of recovering data 
should your system encounter some sort of problem.

3.  Finally, on page 53 of the Windows User's Guide, users are 
cautioned against running CHKDSK /F as well as any other utility 
that will modify the file allocation tables (FAT).  The utilities 
mentioned in this section of the Windows User's Guide are designed 
to operate in a single-tasking environment and include such things 
as undelete or optimization utilities.

In the multi-tasking environment created by Windows, there may be 
many programs creating, manipulating and deleteing files.  While 
these operations are in process, the FATs will not be accurate.  
When the operation is complete, the FAT will accurately reflect that 
operation.  Since there are (or at least could be) multiple programs 
running simultaneously, another application could be in the middle 
of an operation at any given point in time.

Since the file structure is constantly in a state of flux, any 
utility that assumes the structure to be static (unchanging) could 
cause problems if run in this multi-tasking environment.  Be safe, 
run your applications from within Windows and your utilities before 
entering or after exiting Windows.

NOTE:   These utilities can be run successfully after exiting 
Windows or before running Windows; the caution only applies while 
Windows is running.  Going to the DOS prompt from within Windows is 
not the same as exiting Windows and the caution will still apply.

Windows has brought to the PC environment power that has previously 
only been available in mainframe and mini computer environments.  
Even though Windows makes it look like computing just got simpler, 
with this increased power comes increased complexity.  As users we 
need to be aware of this and take precautions such as backing up 
our data before we get on with 'business as usual'.

In as much as data integrity is the cornerstone of our software 
family, we will continue to verify the compatibility of Disk Manager 
and Windows 3.0 (not to mention other software packages).  In the 
event that you or someone you know has actually experienced data 
corruption, we ask that you help us by calling our BBS at 
612-937-0860 and filling out our Windows Survey form.