Filename extension | .trs |
---|---|
Developed by | IBM |
Initial release | 1984 |
Type of format | Data compression |
Open format? | Yes |
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]
The following JCL can be used to invoke AMATERSE on z/OS (TRSMAIN uses INFILE and OUTFILE instead of SYSUT1 and SYSUT2): [6] [7]
//jobnameJOB...//stepnameEXECPGM=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_parametersOptional temporary dataset
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.
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