SAS(R) 9.1.3 Companion for z/OS

48 Hiperspace and DIV Libraries Chapter 2
information about the xlat option, see the IBM documentation for the z/OS
Network File System (NFS).
Table 2.2 File Extensions for SAS Files in HFS Libraries
Random Access
Files
Sequential Access
Files
SAS Member
Type Description
.sas7bdat .sas7sdat DATA SAS data file
.sas7bndx .sas7sndx INDEX data file index; not treated by SAS software as a
separate file
.sas7bcat .sas7scat CATALOG SAS catalog
.sas7bpgm .sas7spgm PROGRAM stored program (DATA step)
.sas7bvew .sas7svew VIEW SAS data view
.sas7bacs .sas7sacs ACCESS access descriptor file
.sas7baud .sas7saud AUDIT audit file
.sas7bfdb .sas7sfdb FDB consolidation database
.sas7bmdb .sas7smdb MDDB multidimensional database
.sas7bods .sas7sods SASODS output delivery system file
.sas7bdmd .sas7sdmd DMDB data mining database
.sas7bitm .sas7ssitm ITEMSTOR item store file
.sas7butl .sas7sutl UTILITY utility file
.sas7bput .sas7sput PUTILITY permanent utility file
.sas7bbak .sas7sbak BACKUP backup file
Hiperspace and DIV Libraries
A hiperspace library is a temporary library in which each library block resides in a
4K block in a z/OS hiperspace, a form of electronic storage internal to the processor.
The hiperspace facility can be exploited for permanent data by defining a
data-in-virtual (DIV) library in which the library blocks are loaded into the hiperspace
for processing and saved permanently in a VSAM linear data set. Hiperspace and DIV
libraries have the same internal format as that of a direct access bound library, and
SAS automatically re-uses free space within the library.
Placing small to moderately sized SAS data sets in a hiperspace or DIV library can
dramatically decrease the elapsed time required for SAS to process such data sets. The
performance increase is usually at least as great as for direct access bound libraries
allocated to VIO and is particularly significant for data sets that are accessed randomly.
However, the actual performance benefit depends on various factors, including the
amount of z/OS expanded storage available to the SAS session. These benefits occur by
default for hiperspace libraries, but the SAS system option NOHSSAVE must be
specified in order to achieve the increase in I/O throughput for DIV libraries. When
specifying NOHSSAVE, design your SAS application carefully to ensure that updates
stored in the DIV library can be re-created, which might be needed if certain types of
abends occur. See “HSSAVE System Option” on page 457 for information on the
NOHSSAVE SAS system option.
The number of hiperspace pages used for hiperspace and DIV libraries is governed by
the HSLXTNTS, HSMAXPGS, and HSMAXSPC SAS system options. When a