2.3.3 PU characterization GLYPH<SM590000> Dedicated Co-Processor (CoP): The dedicated coprocessor is responsible for data  compression and encryption functions for each core. GLYPH<SM590000> Core pervasive unit (PC) for instrumentation and error collection. GLYPH<SM590000> Modulo arithmetic (MA) unit: Support for Elliptic Curve Cryptography: – Vector and Floating point Units (VFU):  GLYPH<129> BFU: Binary floating point unit GLYPH<129> DFU: Decimal floating point unit  GLYPH<129> DFx: Decimal fixed-point unit GLYPH<129> FPd: Floating point divide unit GLYPH<129> VXx: Vector fixed-point unit GLYPH<129> VXs: Vector string unit GLYPH<129> VXp: Vector permute unit GLYPH<129> VXm: Vector multiply unit – L2I/L2D – Level 2 instruction/data cache The PUs are characterized for client use. The characterized PUs can be used in general to  run supported operating systems, such as z/OS, z/VM, and Linux on Z. They also can run  specific workloads, such as Java, XML services, IPSec, and some Db2 workloads, or  clustering functions, such as the Coupling Facility Control Code (CFCC).  The maximum number of characterizable PUs depends on the z15 CPC drawer feature code.  Some PUs are characterized for system use; some are characterized for client workload use.  By default, one spare PU is available to assume the function of a failed PU. The maximum  number of PUs that can be characterized for client use are listed in Table 2-3. The rule for the CP to zIIP purchase ratio is that for every CP purchased, up to two zIIPs can  be purchased. Java and XML workloads can run on zIIPs. However, an LPAR definition can go beyond the 1:2 ratio. For example, a maximum of four  physical zIIPs can be installed on a system with two physical CPs.  Converting a PU from one type to any other type is possible by using the Dynamic Processor  Unit Reassignment process. These conversions occur concurrently with the system  operation. Note:  The addition of ICFs, IFLs, zIIPs, and SAP to the z15 does not change the system  capacity setting or its million service units (MSU) rating. 52  IBM z15 (8561) Technical Guide Table 2-3 PU characterization Feature CPs IFLs Unassigned  IFLs zIIPs ICFs IFPs Std SAPs Add’l SAPs Spare PUs Max34 0-34 0-34 0-33 0-22 0-34 1 4 0-8 2 Max71 0-71 0-71 0-70 0-46 0-71 1 8 0-8 2 Max108 0-108 0-108 0-107 0-70 0-108 1 12 0-8 2 Max145 0-145 0-145 0-144 0-96 0-145 1 16 0-8 2 Max190 0-190 0-190 0-189 0-126 0-190 1 22 0-8 2