For the ICSF-defined services, ICSF checks the integrity of user-passed parameters. An error in a parameter that causes a system abend does not cause a system dump. For an installation-defined callable service, you must perform your own integrity checking of parameters. An error in a user parameter that results in a system abend causes a system dump. You can suppress the system dump by setting a bit on in the SPB. To suppress the dump, set the bit on before you check the integrity of the parameters. This bit (the SPBTERM bit) is the third bit of the flag byte at offset 16 in the SPB.