A single PTF and cumes are noted below. Group PTFs are a collection of PTFs for a particular function of the iSeries such as:
TCP/IP, Websphere, Security, etc.
A PTF is a a software fix for the IBM Code and is made available as soon as it is tested and released.
When you install a PTF, you should always installs all the Cumulatives first. This is just a collection of indivial PTFs from a prior period.