Assume you are ready to actually install a CBPDO or ESO. The following example may help you understand the reasons behind the recommendations made in this topic. In this example:

1. Table 1 shows information about exception SYSMODs. The PTFs and PSP files are as follows:
   1. Column 1 lists the three service levels involved in this example.
   2. Column 2 lists the five SYSMODs in each service level.
   3. Column 3 lists the ++HOLD statements contained on the CBPDO or ESO.

      For simplicity, there are no PE PTFs before the first service level in the example (PUT0701). The exact syntax and APAR numbers for the ++HOLD are not significant for this example.

   4. Column 4 lists the ++HOLD statements contained in the PSP file associated with each of the service levels. The exact syntax and APAR numbers for the ++HOLD are not significant for this example.
2. The SYSMODs have been marked PE as follows:
   • As of the 0701 service level, there were no PTFs in error.
   • Between the 0701 and the 0702 service levels, PTFs UR00002 and UR00003 were marked as PE.
   • Between the 0702 and the 0703 service levels, PTF UR00005 was marked PE.
   • At the 0703 service level, PTF UR00001 was marked as PE.
3. Table 1 shows the contents of each of the files at some time after the creation of the 0703 service level.

   Table 1. CBPDO/service level/PSP HOLDDATA example

   Service level	PTFs per service level	PTFs with HOLDDATA	HOLDDATA in PSP File for the source ID service level
   PUT0701	UR00001 UR00002 UR00003 UR00004 UR00005		UR00001 UR00002 UR00003 UR00005
   PUT0702	UR00006 UR00007 UR00008 UR00009 UR00010	UR00002 UR00003	UR00001 UR00005
   PUT0703	UR00011 UR00012 UR00013 UR00014 UR00015	UR00005	UR00001

4. You are now trying to install PTFs at service level 0701. The amount of processing you have to do before installing 0701 service level PTFs depends on what you did with PTFs in 0702 and 0703 service levels.
   • If you received the HOLDDATA for service levels 0701, 0702, and 0703, you have to process only the one ++HOLD statement for PTF UR00001 from the PSP file for service level 0703.
   • If you received only the HOLDDATA for service level 0702, you have to process the two ++HOLD statements for PTFs UR00001 and UR00005 from the PSP file for service level 0702.
   • If you decided not to process any data for particular service levels until you are ready to install them (that is, if you did nothing with service level 0702 or 0703), you have to process the four ++HOLD statements for PTFs UR00001, UR00002, UR00003, and UR00005 from the PSP file for service level 0701.
   Note: In each case, you used the PSP file associated with the last service level for which you received the HOLDDATA, but if you had kept current in processing the exception SYSMOD files from the service levels, you would have had less information to obtain from the IBM® Support Center.

   In this example, the number of PTFs and HOLDDATA was small and, thus, the data seems manageable. However, with a real service level with hundreds of PTFs, the amount of manual work involved in getting the ++HOLD statements from IBMLINK or the IBM Support Center, and then keying them into a data set and receiving them could be very time-consuming. So, the cost of the increased DASD space necessary to store the HOLDDATA each month is commonly paid back in increased programmer productivity when the service level is to be installed.