Physical Sequential Transparency › Implementing Compressed Data Sets with the IUI

Implementing Compressed Data Sets with the IUI

If the data set is already compressed, the IUI marks it COMPRESD on the Work List and analysis is not permitted. If the IUI is able to determine the FDT name or compression algorithm, implementation can be done only with that name. If the IUI cannot determine the FDT, you can enter the correct FDT.

Remember that if a data set is already compressed, you cannot really select a compression method. The compression selection has already been made, so you can only tell CA Compress what it is if the IUI is unable to determine it. To select a different Compression method, you must uncompress and reimplement the data set.