Ref: Your note of Tue, 1 Apr 2014 19:26:04 -0700 The HLASM product has always used a single chain of maintenance rather than a tree, and provided the INFO option to list the product changes. I don't know the specific reason that this choice was made, over 20 years ago, but as HLASM uses common code across four platforms (MVS, CMS, VSE and more recently zLinux) I suspect it would be much more complex and error-prone to handle the maintenance in any other way.
The hypothetical situation where one might want to install one fix without installing other fixes does not seem very likely to arise. HLASM has a general rule that valid input will continue to produce the same object code output, so fixes are not likely to result in side-effects. It's not possible to totally eliminate the possibility of a PTF occasionally being in error and someone wanting to apply a fix which prereqs that PTF before the PE fix is available, but that is already an undesirable situation which every effort will be made to avoid. My personal opinion is that on past experience this situation seems to be sufficiently rare that the benefits to users and to the IBM change team of using a simple sequential maintenance process far outweigh the potential impact of rare cases of wanting to apply fixes out of sequence. Jonathan Scott IBM Hursley, UK Disclaimer: I do not speak for IBM
