Category : HD Utilities
Archive   : STACTECH.ZIP
Filename : 2502.TXT

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STACKER NOTE STACKER NOTE
Title: Performance Differences Between Stacker Software and Coprocessor
Versions (AT/16 and MC/16).
STAC FAX Index #2502 - 2/20/92
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Background.

Stacker's software is supplemented and enhanced by the coprocessor card.
The Stacker coprocessor card yields the highest compression of data, the
smallest device driver and the fastest I/O.


What performance increases will I see with the coprocessor?

1. Hardware compression offers as much as 10-20% more disk space;

2. Disk reads and writes are 5-15% faster. This higher performance
is especially apparent on slower 8088/8086 and 80286 machines.

3. The device driver memory requirements with the Stacker coprocessor card
are as little as 14k vs. a minimum of 26k for the software version.

What if the coprocessor stops working?

If the coprocessor card does not respond to the Stacker device driver when
the system starts up, Stacker will run in the software mode and produce
the following message: driver>. This means that Stacker is fully operational, only it is running
without the benefits of the card. For AT/16 trouble shooting guidelines
see STAC FAX index #2001, "Stacker Coprocessor Card Installation Checklist".

Is is difficult to upgrade to the coprocessor from the software version?

Upgrading from the software to the coprocessor version does not require
that you re-stack your drives. However, only those files written to the
drive with the coprocessor benefit from the higher compression. With
Stacker 2.0, all the files can be recompressed by the Stacker coprocessor
by running Stacker's SDEFRAG disk optimizer with the /R parameter. For
example, to recompress Stacker drive C:

type: SDEFRAG /R C:

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Copyright 1993, Stac Electronics