How to control the parmlib

With a parmlib concatenation, you have more flexibility in managing parmlib members and changes to parmlib members. To control parmlib and ensure that it is manageable, you need to consider the following:

• The RACF® (or other security product) read access is a must for applications that need to read SYS1.PARMLIB.
• Use the ability to have up to 16 installation-defined parmlib data sets separate your parmlib members along organization or function lines and use appropriate RACF security for each data set.
• Include members with installation changes in one of the 16 installation-defined parmlib data sets to avoid having the member overlaid by IBM® maintenance on SYS1.PARMLIB.
  Note: If a member exists more than once within the parmlib concatenation, the first occurrence is used.
• Use an installation-defined parmlib data set to contain any parmlib members to be used on test systems. They can be included in front of your "standard" parmlib concatenation without forcing changes to the "standard" parmlib concatenation.
• Delete unsupported parameters and members. Because most components treat unsupported parameters from previous releases as syntax errors, you probably need to remove the old parameters or build parmlib from scratch. This action minimizes the need for operator responses during an IPL. Then, you can save space by removing unsupported members.
• Use the parmlib members for the appropriate functions. For example, use COMMNDxx to contain commands useful at system initialization. Use IEACMDxx for IBM*-supplied commands. Use IEASLPxx for SLIP commands. See each member for further information.
• Update the parmlib with new and replacement members, as you gain familiarity with the new release.
• Keep track of which parameters are included in particular parmlib members. This bookkeeping is necessary for two reasons: 1) The system does not keep track of parmlib members and their parameters and 2) The default general parameter list IEASYS00 is always read by the system and master scheduler initialization. The parameters in IEASYS00 can be overridden by the same parameters when they are specified in alternate general lists, such as IEASYS01, or IEASYS02. Then, certain parameters, such as FIX, APF, and MLPA, direct the system to particular specialized members (in this example, IEAFIXxx, and IEALPAxx). The installation should keep records of which parameters and which values are in particular members, and which general members point to which particular specialized members (COMMNDxx, IEALPAxx, and so forth). A grid or matrix for such bookkeeping is very helpful.
• Allocate sufficient space for parmlib. One way to estimate space is to count the number of 80-character records in all members which are to be included in one parmlib data set and factor in the block size of the data set. Then add a suitable growth factor (e.g., 100-300%) to allow for future growth of alternate members. Consult Table 1 to determine which members can have multiple alternates. To recapture space occupied by deleted members, use the "compress" function of IEBCOPY. However, should the data set run out of space, you can copy the members to a larger data set, create a new LOADxx member in which you replace the PARMLIB statement for the full data set with a parmlib statement for the new larger data set, and then issue a SETLOAD command to switch to the concatenation with the new data set.
• Ensure EXITxx resides in SYS1.PARMLIB, because you can only access it from SYS1.PARMLIB.
• GTFPARM must also reside in SYS1.PARMLIB unless an alternate data set is used, as discussed in GTFPARM (generalized trace facility parameters).
• Decide which volumes and devices should hold the parmlib concatenation. You must catalog the data set, unless it resides in SYSRES or its volume serial number is included in the parmlib statement in LOADxx. You can place the data set on a slow or moderate speed device.
• Use a security product (like RACF*) to protect the data sets. The purpose is to preserve system security and integrity by protecting various members that define authorized programs and libraries, including but not limited to the appendage member (IEAAPPxx), the authorized program facility members (IEAAPFxx and PROGxx), the LPA libraries (LPALSTxx, IEALPAxx, PROGxx), and the link libraries (LNKLSTxx). In addition, ensure that you protect any libraries that are named in those members to ensure that only appropriate users with system maintenance responsibility can update them.