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SAS Library Engines

To access a SAS data library, SAS needs a libref and a library engine. You assign a libref to the SAS data library, for example, using the LIBNAME statement, but usually you do not have to specify an engine because SAS automatically selects the appropriate one. For base SAS software, Version 8 provides the following library engines.

Note:   Engine availability is platform dependent. See the SAS documentation for your operating environment. Also, specific SAS products provide additional engines.  

Operating Environment Information

Version 8 Base SAS Software Library Engines

Type Of Engine	Engine Name	Description
Default Version 8 engine	V8 (or V7, V701, BASE)	Creates and accesses Version 8 SAS files and accesses Version 6 and Version 7 SAS files.
Version 8 sequential engine	V8TAPE (or TAPE, V7TAPE)	Creates and accesses Version 8 SAS files and accesses Version 6 and Version 7 SAS files on storage media that do not allow random access methods, for example, tape or sequential format on disk.
Version 6 compatibility engine	V6 (or V608, V609, V610, V611, V612)	Creates and accesses SAS files created by Release 6.08 through Release 6.12 without converting to Version 8 format. :   For Version 6 files prior to Release 6.08, see the SAS documentation for your operating environment.
Version 6 sequential engine	V6TAPE	Creates and accesses Version 6 SAS files on storage media that does not allow random access methods, for example, tape or sequential format on disk.
Transport	XPORT	Accesses transport files. This engine creates machine-independent SAS transport files that can be used for all hosts.
Version 5 compatibility engine	V5	Accesses Version 5 SAS files without converting to Version 8 format. On OS/390 and CMS, the V5 engine is read only. On VMS, the V5 engine is both read and write. This engine cannot access Version 6 or later files.

If you do not specify an engine name, SAS automatically assigns an engine based on the contents of the data library. That is, SAS is able to differentiate between Version 6 libraries and those in later releases, because the engine that creates a SAS file determines its format and the format is different between Version 6 and later versions.

For example, in a Version 8 SAS session, if you issue the following LIBNAME statement to assign a libref to a data library containing only Version 6 SAS files, SAS automatically assigns the V6 compatibility engine:

libname mylib "SAS-data-library";

SAS automatically assigns an engine based on the contents of the data library as shown in the following table:

Default Library Engine Assignment

Engine Name Assignment	Data Library Contents
V8	No SAS files; the library is empty
V8	Only Version 8 SAS files*
V6	Only Version 6 SAS files*
V8	Both Version 8 SAS files and SAS files from earlier releases
V8TAPE	Both Version 8 TAPE files and TAPE files from earlier releases

* If a library contains only files that were created from a single engine, that engine is the default. Note that Version 8 and Version 7 files are created from the same engine.

Note:   Even though SAS will automatically assign an engine based on the library contents, it is more efficient to specify the engine name in a LIBNAME statement. For example, specifying the engine name in the following LIBNAME statement saves SAS from determining which engine to use:

libname mylib v6 "SAS-data-library";

  

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