SAS(R) 9.1.3 Companion for z/OS

424 DSRESV System Option Chapter 18
Syntax
DLTRUNCHK | NODLTRUNCHK
Details
The first time a SAS data library is accessed after it is assigned, SAS compares the
external count of library blocks from the z/OS data set label with the internal count of
library blocks from the library itself. If the external count is less, the library may be
truncated, or the external count may merely be in error. In either of these cases
(apparent or actual truncation), if the DLTRUNCHK option is in effect, SAS issues an
error message and refuses to process the library in any manner. If NODLTRUNCHK is
in effect, SAS attempts to continue processing; however, if the library is truncated, no
write access is allowed. If you specify NODLTRUNCHK, SAS also attempts to correct
the external count, if possible, when closing the library or when extending the library to
a new volume. However, this repair is not possible if the library is actually truncated or
the SAS session does not have write access to the library.
DLTRUNCHK is the default setting, and it is recommended for all production
applications for the following reasons:
3 Attempting to read or update a library that is truncated might result in the SAS
session terminating with an abend. Therefore, if you are running a SAS/SHARE
server, it is recommended that you specify DLTRUNCHK to prevent the server
from terminating for that reason.
3 If you use NODLTRUNCHK, there is a small risk that SAS will accept as valid
any residual data on a disk that is from a deleted z/OS data set.
DSRESV System Option
Requests exclusive use of shared disk volumes when accessing partitioned data sets on shared
disk volumes
Default: NODSRESV
Valid in: configuration file, SAS invocation, OPTIONS statement, OPTIONS window
Category: File Control: EXTFILES
PROC OPTIONS GROUP= EXTFILES
z/OS specifics: all
Syntax
DSRESV | NODSRESV
DSRESV
reserves the device, which prevents other processors from accessing the volume on
which the partitioned data set resides.
NODSRESV
enqueues the resources that are defined by the operating environment.