Compression Utility
-------------------

Patient files on the Work Bench will be Compressed
or Uncompressed.  Compressed files will take much
less space on the disk for storage, but cannot be
processed or displayed.  The disk space required 
for a compressed file will be approximately 1/6
to 1/3 of the disk space required for the original
file.

A patient subdirectory may contain a mixture of
compressed and uncompressed files.  This should
cause no problems, except that the compressed 
files must be uncompressed before then can be 
displayed or processed.

The user interface will handle up to 100 files.
If you put more than 100 files on the workbench,
only the first 100 will be processed.

Compressed files can be transferred using the 
normal Patient Transfer Utility.  After transfer, 
the new files can be uncompressed by putting them 
on the Work Bench and using the Compression 
Utility.

If you run the Picker "cibuild" utility, the
compressed files will look normal, and there will
be no indication in the Clinical Index that the
files are compressed.

Compression is applied to files in the following 
categories:  raw data, transverse reconstructions, 
oblique reconstructions, and lightboxes.  Other
types of files will not be compressed or 
uncompressed.

The compression is performed by the standard unix
utility which uses adaptive Lempel-Ziv coding.

Some sites have modified the Compression Utility
To only allow compression on the optical disks,
and block compression on the fixed disks.  You
can do this by editing the "arch" script in the
"$SITE" directory.  Look for the line in the
script that says "EDIT HERE".


Good Luck!

--------------------------------
arch script written by:
Eugene Mah, MSc Graduate Student
(eugene@raddi.uah.ualberta.ca)

University of Alberta Hospitals
Edmonton, Alberta, Canada
--------------------------------
--------------------------------
cmprss interface written by:
Wesley Wooten, Ph.D.   
(wooten@medisun.ucsfresno.edu)

Saint Agnes Medical Center
Fresno, California
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------------------------------
Wesley Wooten, Ph.D.   
(wooten@medisun.ucsfresno.edu)

Saint Agnes Medical Center
Fresno, California
------------------------------