Packing data

Data can be saved in either packed or standard format. You can control the format by using the PACK primary command to change the edit profile. The editor reads the data in and you can edit it the way you normally would. When you end the editing session, the data is packed and stored. See PACK—Compress Data and PACK—Set or Query Pack Mode for more information.

The packed data format has the advantage of saving space. It allows for a more efficient use of DASD by replacing repeating characters with a sequence that shows the repetition.

There are two disadvantages:

The space saving is at the expense of additional processing when the data is read or written.
The data cannot be directly accessed by programs. You must access the data through PDF dialogs and library access services. You would not, for example, pack an executable such as a CLIST or REXX exec. A packed CLIST or REXX exec would not run, because pack mode analysis is not done before the member is passed to the system for execution.