Physical Sequential Transparency › Implementing Uncompressed Data Sets with the IUI

Implementing Uncompressed Data Sets with the IUI

While the IUI is building the Work List, it determines whether each PS data set is already compressed. If it is uncompressed, you implement it much like a VSAM data set. You can explicitly analyze it or you can pick a compression method and go directly to implementation.

If the IUI is running in Scheduled mode, it implements the data set online by adding a Control File entry with an effective date of today with the DCB attributes of the uncompressed data set. The data set is compressed the next time it is loaded.

If the IUI is running in Choice mode, you can specify all the values supported by the CFMU, including GDG, ERASEUNCAT, and NON-COMP. If you specify a nonzero effective date, the IUI implements the data set online with the values you specify, and the data set is compressed the next time it is loaded. If you specify ANYDATE, the IUI generates JCL to reload and compress the data set immediately, in the same way that it supports VSAM immediate compression.