FILEDISP= Data Set Option: z/OS

Specifies the initial disposition for a sequential access bound SAS library.
Valid in: DATA step, PROC steps
Default: OLD
Engine: V9TAPE, V8TAPE, V7TAPE, V6TAPE, V5TAPE
z/OS specifics: All

Syntax

FILEDISP=NEW | OLD

Required Arguments

NEW
specifies that the sequential library is to be considered empty. SAS therefore does not look for previously written members. The DATA step writes the new member at the beginning of the new (empty) library. Any members that existed in the library before the write operation are lost. The FILEDISP=NEW option can be valid only during the first write to a sequential library for a given libref. For all subsequent writes to that libref, FILEDISP=NEW is ignored and FILEDISP=OLD is assumed.
OLD
specifies that the sequential library is not initially empty. SAS therefore writes members with names that do not already exist in the library at the end of the library. If the member being written has a name that already exists in the library, the existing member is overwritten, and any members that follow the overwritten member are lost.

Details

A sequential library is a single SAS file that can contain one or more concatenated members.
To avoid inadvertent data loss, make sure that you specify FILEDISP=NEW only when writing to new (empty) sequential libraries. Also, when writing to an existing sequential library, make sure that the name of the member being written does not inadvertently correspond to the name of a member that already exists in the library.