Terse (file format)
| Filename extension | .trs |
|---|---|
| Developed by | IBM |
| Initial release | 1984 |
| Type of format | Data compression |
TERSE is an IBM archive file format that supports lossless compression. A TERSE file may contain a sequential data set, a partitioned data set (PDS), partitioned data set extended (PDSE), or a large format dataset (DSNTYPE=LARGE). Any record format (RECFM) is allowed as long as the record length is less than 32 K (64 K for RECFM=VBS). Records may contain printer control characters.[1]
Terse files are compressed using a modification of Ziv, Lempel compression algorithm developed by Victor S. Miller and Mark Wegman at the Thomas J. Watson Research Center in Yorktown Heights, New York.[2][3]
The Terse algorithm was proprietary to IBM; however, IBM has released an open source Java decompressor under the Apache 2 license.[4] The compression/decompression program (called terse and unterse)—AMATERSE or TRSMAIN—is available from IBM for z/OS; the z/VM equivalents are the TERSE and DETERSE commands, for sequential datasets only. Versions for PC DOS, OS/2, AIX, Windows (2000,XP,2003), Linux, and Mac OS/X are available online.[5]
AMATERSE
The following JCL can be used to invoke AMATERSE on z/OS (TRSMAIN uses INFILE and OUTFILE instead of SYSUT1 and SYSUT2):[6][7]
//jobname JOB ... //stepname EXEC PGM=AMATERSE,PARM=ppppp //SYSPRINT DD SYSOUT=* //SYSUT1 DD DISP=SHR,DSN=input.dataset //SYSUT2 DD DISP=(NEW,CATLG),DCB=ddd,DSN=output.dataset, // SPACE=space_parameters //SYSUT3 DD DISP=(NEW,DELETE),SPACE=space_parameters Optional temporary dataset
Uses
Terse can be used as a general-purpose compression/decompression tool. IBM also distributes downloadable Program temporary fixs (PTFs) as tersed datasets. Terse is also used by IBM customers to package diagnostic information such as z/OS dumps and traces, for transmission to IBM.
References
- ↑ IBM Corporation (25 August 2016). "AMATERSE: Pack and unpack a data set". https://www.ibm.com/support/knowledgecenter/SSLTBW_2.2.0/com.ibm.zos.v2r2.ieav100/terse.htm.
- ↑ Miller, Victor S.; Wegman, Mark N. (1988). "Variations on a theme by Ziv and Lempel (Data compression)". IEEE International Conference on Communications, - Spanning the Universe. pp. 390–394. doi:10.1109/ICC.1988.13597. http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=720. Retrieved Sep 4, 2016.
- ↑ Lalonde, Bill. "Terse/MVS". http://billlalonde.tripod.com/terse.htm.
- ↑ "openmainframeproject/tersedecompress" (in en). https://github.com/openmainframeproject/tersedecompress.
- ↑ "Hercules-390". https://groups.yahoo.com/neo/groups/hercules-390/files.
- ↑ IBM Corporation (25 August 2016). "Specifying the JCL statements for AMATERSE". https://www.ibm.com/support/knowledgecenter/SSLTBW_2.2.0/com.ibm.zos.v2r2.ieav100/jclama.htm.
- ↑ ppppp is PACK (compress), SPACK (compress, slower and compresses better), or UNPACK (uncompress)
External links
 |  |
