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## 2.8.2 Model capacity identifier 

To recognize how many PUs are characterized as CPs, the Store System Information (STSI) instruction returns a Model Capacity Identifier (MCI). The MCI determines the number and speed of characterized CPs. Characterization of a PU as an IFL, ICF, or zIIP is not reflected in the output of the STSI instruction because characterization has no effect on software charging. For more information about STSI output, see “Processor identification” on page 375. 

The following distinct model capacity identifier ranges are recognized (one for full capacity and three for granular capacity): 

GLYPH<SM590000> For full-capacity engines, model capacity identifiers 701 - 7J0 are used. They express capacity settings for 1 - 190 characterized CPs. 

GLYPH<SM590000> Three model capacity identifier ranges offer a unique level of granular capacity at the low end. They are available when no more than 34 CPs are characterized. These three subcapacity settings are applied to up to 34 CPs, which combined offer 102 more capacity settings. For more information, see “Granular capacity”. 

## Granular capacity 

The z15 server offers 102 capacity settings at the low end of the processor. Only 34 CPs can have granular capacity. When subcapacity settings are used, other PUs beyond 34 can be characterized only as specialty engines. 

The three defined ranges of subcapacity settings have model capacity identifiers numbered 401- 434, 501 - 534, and 601 - 634. 

Consideration:  All CPs have the same capacity identifier. Specialty engines (IFLs, zIIPs, and ICFs) operate at full speed. 

## List of model capacity identifiers 

Regardless of the number of CPC drawers, a configuration with one characterized CP is possible, as listed in Table 2-11. 

<img src='content_image/971576.jpg'>

For more information about temporary capacity increases, see Chapter 8, “System upgrades” on page 331. 

