SAS(R) 9.1.3 Companion for z/OS

Using SAS Data Libraries HFS Libraries 47
the engine. The various options for reserving space and specifying DCB attributes
are not required, nor do they apply to HFS libraries.
Creating HFS Libraries
Creating an HFS library is as simple as creating a SAS file in a particular library
directory, as shown in the following example:
libname myproj ’/u/user905/MyProject’;
data myproj.member1;
...
run;
If the library directory does not exist, SAS will automatically create the directory if
possible. In the example above, the directory node MyProject would have been created
if it did not already exist, provided the SAS session had adequate authority to do so.
However, the other directories in the directory path must exist before you attempt to
create the library.
General Usage Notes
3 The fully qualified name of a SAS file in an HFS library is
/.
The member name in this construction is formed by converting to lowercase the
member name specified in the SAS session. The filename extension for a SAS file
is automatically supplied by SAS and indicates the member type and the engine
that was used to create the file. For a list of extensions used, see Table 2.2 on page
48. Do not change the filename extension of a SAS file because that could cause
unpredictable results. The total length of the fully qualified name must not exceed
254 characters. This is more restrictive than the IBM limits on HFS filenames.
3 When SAS creates or updates a member of an HFS library, it places an exclusive
lock on the individual file (but not on the library). The lock prevents other jobs,
processes, or SAS sessions from reading, writing, or updating that file until SAS
finishes using the file, at which time the lock is removed. It is still possible for
other SAS sessions to access other SAS files in the library, provided they are
unlocked. The write lock is analagous to the SYSDSN enqueue that is issued when
a data set is allocated with DISP=OLD.
3 When SAS reads an existing member of an HFS library, it places a read (or
shared) lock on the individual file, which prevents other jobs, processes, or SAS
sessions from updating the file, although it is still possible for others to read the
file. The read lock is analagous to the SYSDSN enqueue that is issued when a
data set is allocated with DISP=SHR.
3 In performance testing at SAS, native HFS libraries have demonstrated I/O
throughput rates that, for a variety of access patterns, generally match or exceed
those demonstrated for direct access bound libraries.
3 Although it is possible to externally allocate an HFS library via JCL or the TSO
ALLOCATE command, doing so does not lock or reserve the library in any way.
The main benefit of external allocation is to provide a convenient way to specify a
different library for a particular job.
3 When using NFS client capability to access SAS files in other operating
environments, specify the xlat(n) option for the NFS mount point on z/OS.
Similar options might need to be specified in other operating environments when
you are accessing SAS files shared by an NFS server running on z/OS. For