When the service team has found a fix for your problem, you may be asked to test it on your system. If so, you may be sent a Program Temporary Fix (PTF) in the form of individual replacement modules. This is normally done through the Level-2 organization and feedback from your testing will be requested.
Each PTF may contain several APAR fixes. If an individual APAR fix within a PTF is found to be in error, it may still be advisable to apply the PTF, to obtain the other APAR fixes.
In time, formal corrective service software is made available, which you can order through your support organization. Traditionally, corrective service software has been supplied on Corrective Service Diskettes (CSD) ordered by CSD number. It may now be supplied on CD-ROM or via the Internet.
www.ibm.com/software/ts/cics/support/