The packed data set format allows you to use direct access
storage devices (DASD) more efficiently. In this format, ISPF replaces any
repeating characters with a sequence showing how many times the character
is repeated. Before you can properly use data stored in this format
as input to processing programs, such as compilers, you must first
tell ISPF to unpack and expand the data.
The two requirements for using packed data sets are:
- To store data in packed format:
- Enter the PACK ON Edit primary command while editing a data set
or PDS member.
- Select the Pack Option field (under To Data Set Options:) when
copying or moving members using the Move/Copy utility (option 3.3).
- To unpack and expand packed data for processing, select the Source
Data Packed field on the Foreground Selection panel or the Batch Selection
panel. You must select this field if any of the input data, including
that referred to in COPY or INCLUDE statements, is in packed format.