System programmer tips

  • If you do a lot of application development on your machine, put the compiler and runtime library in the LPA. Similarly, if you are working in z/OS® UNIX System Services also put the c89/cxx/cc utilities in the dynamic LPA, LPA or linklist.
  • Use packs that are cached with DASD fast write.

    If you are working in z/OS UNIX System Services, give each user a separate mountable file system to avoid I/O contention.

    If the compiler is not in LPA, tune your jobs to avoid channel and pack contention when the headers and the compiler are on the same pack and multiple compile jobs are executing.

  • If you use the makedepend utility to generate dependency information, use the LIST option to generate a listing from makedepend. The summary section of this listing shows a list of the most frequently called headers and the frequency of these calls. Use this information to determine which headers should be cached.
  • You can define /tmp as a RAM disk by specifying: 
    FILESYSTYPE TYPE(TFS) ENTRYPOINT(BPXTFS)

    This is described in more detail in z/OS UNIX System Services Planning.