The number of permanent zIIPs plus temporary zIIPs cannot exceed twice the number of  purchased CPs plus temporary CPs. Also, the number of temporary zIIPs cannot exceed the  number of permanent zIIPs. zIIPs are dedicated or shared, depending on whether they are part of an LPAR with dedicated  or shared CPs. In an LPAR, at least one CP must be defined before zIIPs for that partition can  be defined. The number of zIIPs that are available in the system is the number of zIIPs that  can be defined to an LPAR. LPAR:  In an LPAR, as many zIIPs as are available can be defined together with at least  one CP. zIIPs and logical partition definitions 3.5.6 System assist processors 3.5.7 Reserved processors 118  IBM z14 (3906) Technical Guide A system assist processor (SAP) is a PU that runs the channel subsystem LIC to control I/O  operations. All SAPs run I/O operations for all LPARs. z14 is the first IBM Z server to enable  SMT for SAPs. All models feature standard SAPs configured. The number of standard SAPs  depends on the z14 model, as listed in Table 3-2. A standard SAP configuration provides a well-balanced system for most environments.  However, some application environments have high I/O rates, typically Transaction  Processing Facility (TPF) environments. In this case, more SAPs can be ordered. Assigning  of more SAPs can increase the capability of the channel subsystem to run I/O operations. In  z14 systems, the number of SAPs can be greater than the number of CPs. However, more  SAPs plus standard SAPs cannot exceed 128. The option to order more SAPs is available on all models (FC #1935). These extra SAPs  increase the capacity of the channel subsystem to run I/O operation, which is suggested for  TPF environments. The maximum number of optional extra orderable SAPs depends on the  configuration and the number of available uncharacterized PUs. The number of SAPs is listed  in Table 3-3. Table 3-3 Optional SAPs per model Table 3-2 SAPs per model SAP configuration Optional other orderable SAPs Reserved processors  are defined by the PR/SM to allow for a nondisruptive capacity upgrade.  Reserved processors are similar to spare logical processors, and can be shared or dedicated.  Reserved CPs can be defined to an LPAR dynamically to allow for nondisruptive image  upgrades. Model  M01  M02 M03 M04 M05 Standard SAPs 5 10 15 20 23 Model  M01  M02 M03 M04 M05 Optional SAPs 0 - 4 0 - 8 0 - 12 0 - 16 0 - 16