Unix System Services

Unix System Services (USS) is a component of z / OS. USS is a fully certified UNIX implementation ( XPG4 UNIX 95). It is the first UNIX 95, which was not derived from the AT & T / SCO source code. Through integration with z / OS in addition to the usual Unix services TSO commands are available and it is possible to process Unix files using ISPF. Extensions in the Job Control Language it possible to use these files in batch processing.

Unix System Services allows it to run on IBM mainframes and Unix applications to implement unix -based services on those machines. The only incompatibility form programs that are based in their logic on the numerical values ​​of ASCII characters. The architecture of the System z is based on EBCDIC.

Programs running under USS, also have full access to the functions of z / OS. This is for example used for database connections (DB2 via Call Attach). Such programs are then no longer portable.

The file systems of the USS (HFS and zFS ) in the opinion of other z / OS specific datasets.

Precursor of Unix System Services was an operating system component called Open Edition MVS, which was implemented for the first time in MVS / ESA 4.3 and only implemented the POSIX standards.

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