IBM z/OS manual Z990 I/O SubSystem, Z990 Cage Layout

z990 I/O SubSystem

•Comparing a 16-way z900 Model 216 to a z990 model with sixteen CPs enabled, it is estimated that the z990 model has 1.45 to 1.53 times the capacity of the 216.

•Comparing a 16-way z900 Model 216 to a z990 model with thirty-two CPs enabled, and the workload execut- ing on the z990 executing in two 16-way LPARs, it is estimated that the z990 model has 2.4 to 2.9 times the capacity of the 216.

Model D32

Model C24

Model B16

Model A08

z900	2C1 2C2 2C3 2C4 2C5 2C6 2C7 2C8 2C9 210 211 212	213 214 215	216
Turbo
z900	1C1 1C2 1C3 1C4 1C5 1C6 1C7 1C8 1C9 110 111 112	113 114 115	116

Note: Expected performance improvements are based on hardware changes. Additional performance benefits may be obtained as the z/Architecture is fully exploited.

The z990 contains an I/O subsystem infrastructure which uses an I/O cage that provides 28 I/O slots and the abil- ity to have one to three I/O cages delivering a total of 84 I/O slots. ESCON, FICON Express™ and OSA-Express features plug into the z990 I/O cage along with any ISC- 3s, STI-2 and STI-3 distribution cards, and PCICA and PCIXCC features. All I/O features and their support cards can be hot-plugged in the I/O cage. Installation of an I/O cage remains a disruptive MES, so the Plan Ahead feature remains an important consideration when ordering a z990 system. The A08 model has 12 available STIs and so has connectivity to a maximum of 12 I/O domains, i.e. 48 I/O slots, so if more than 48 I/O slots are required a Model B16 is required. Each model ships with one I/O cage as stan- dard in the A-Frame (the A-Frame also contains the pro- cessor CEC cage) any additional I/O cages are installed in the Z-Frame. The z990 provides a 400 percent increase in I/O bandwidth provided by the STIs.

z990 Cage Layout

Z-Frame A-Frame

3rd	CEC
I/O Cage

2nd	1st
I/O Cage	I/O Cage

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