You can use either IEAMSCHD or SCHEDULE to schedule an SRB routine. IBM® recommends that you use IEAMSCHD. The following table provides a comparison of the two macros:
| IEAMSCHD | SCHEDULE |
|---|---|
| IEAMSCHD obtains storage for the SRB for the caller, and frees the storage when SRB processing is complete. | Caller must obtain storage for the SRB. |
| When the SRB routine gets control, Register 0 contains zeros. | When the SRB routine gets control, Register 0 contains the address of the SRB. |
| RMTR and FRR are optional. | RMTR and FRR required to free storage at termination of SRB and when an error occurs. |
| Schedules an SRB at any of the following priorities: local, global, current, preemptable, client, and enclave. | Schedules an SRB at either global or local priority. |
| IEAMSCHD initializes SRB fields in IHASRB for caller. | Caller must initialize SRB fields in IHASRB. |