30. Larger memory capacity The System z9 supports twice its immediate predecessors' maximum memory configurations: now up to 512 GB for the z9 EC and up to 64 GB for the z9 BC. Concurrent system board replacement The System z9 supports nondisruptive processor and memory replacement. That means a technician can replace an entire system board without ending any applications and without restarting any operating systems. In most configurations a System z9 can even manage this feat without any reduction in performance or capacity for the running applications. 4 Gbit FICON and FCP In May 2006, IBM added 4 Gigabit FICON and FCP support to the System z9 for faster I/O to storage devices. IBM also added a lower cost 2-port 4 Gbit FICON/FCP I/O adapter to the System z9 option list. Smooth subcapacity increments Also in May 2006, IBM introduced subcapacity settings to its high end model. For the first time mainframe processors now allow small, smooth steps through the entire processor range. This feature allows IBM's customers to control their software costs precisely and to pay for only exactly as much capacity as they need without harsh price discontinuities at certain capacity increments. (IBM started offering variable subcapacity software pricing in 2000, and some other software vendors now offer similar terms, so hardware subcapacity settings are of primary interest when running so-called full capacity software products.) Group capacity limits Available with z/OS Release 8, Group Capacity Limits allows an installation to define a group of LPARs within a single z9 or z10 machine whose capacity usage can be limited to a specific number of MSUs. Usage is based on the rolling 4 hour average CPU consumption, also in MSUs. A group need not necessarily be the same as an LPAR Cluster. LPARs can participate whether they are in a sysplex or not. Separate processor pools While previous mainframe generations (including the predecessor zSeries z990) supported specialty processors, such as zAAPs and ICFs, these were all managed by PR/SM out of the same processor pool (Pool 2). The IBM System z9 EC introduced the concept of separate pools for different types of specialty processor. This greatly eases the tasking of managing and measuring the performance of the different processor types. With z9 (and IBM System z10) the following pools are defined: 1 General-purpose processors 3 IFLs 4 zAAPs 5 ICFs 6 Pool 2 is no longer used. In addition