SAS(R) 9.1.3 Companion for z/OS

x alloc dd(result2) path(’/corp/dev/test2’);
Using SAS Data Libraries How SAS Assigns an Engine 59
Note that allocating HFS libraries in this way provides a convenient way to
establish an external logical name (DDname) for an HFS library. No enqueue is
placed on the library.
3 Allocating a new SAS data library
The following TSO command allocates a new sequential SAS data library on
disk:
alloc fi(intape) da(V9.seqdata) dsorg(ps) recfm(u) new
Notice that DCB attributes are specified. When you allocate a new SAS data
library externally, you must either specify DCB attributes or accept the default
DCB attributes that SAS supplies.
3 Specifying additional options for a previously allocated SAS data library
See “Specifying an Engine for Externally Allocated SAS Data Libraries” on page
59.
Using a DDname as a Libref
Even though a library has been allocated to a DDname externally to SAS, the
assignment process is not complete until the library has been referred to within a SAS
program or feature that specifies the DDname as a libref. At that point SAS completes
the assignment process and adds the DDname to its table of active librefs. For example:
proc contents data=books._all_; run;
The first time that the DDname BOOKS is used in this manner, SAS assigns it as a
libref for the SAS data library.
When a DDname is allocated externally, it is not listed by the LIBNAME LIST
statement or in the SAS Explorer until after you have used it as a libref in your SAS
session. (See “Listing Your Current Librefs” on page 61.)
Specifying an Engine for Externally Allocated SAS Data Libraries
In most cases, SAS can identify the proper engine to use for existing libraries.
However, when creating new libraries that were allocated externally, you might need to
use the LIBNAME statement or LIBNAME function to override the engine that SAS
would use by default. For example, suppose you used an X statement to submit the
following TSO ALLOCATE command, which allocates the SAS data library
QUARTER1.MAILING.LIST:
x alloc f(mail) da(’quarter1.mailing.list’) new
dsorg(ps) space(10 1) cyl;
You could instruct SAS to use the V9TAPE engine for this new library with the
following statement:
libname mail tape;
This LIBNAME statement does not need to specify the name of library data set or
any other options, because that information was supplied on the external allocation
referenced by the DDname mail.
How SAS Assigns an Engine
In some cases, you might choose not to specify an engine name in the LIBNAME
statement or LIBNAME function, or you might choose not to issue a LIBNAME