IBM 990 - Manual (Page 46)

34 IBM
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zSeries 990 Technical Guide
A frame
As shown in Figure 2-9 on page 33, the main components in the A-frame are:
1. Two Internal Battery Features (IBFs)
The optional Internal Battery Feature provides the function of a local uninterrupted power
source.
The IBF further enhances the robustness of the power design, increasing Power Line
Disturbance immunity. It provides battery power to preserve processor data in case of a
loss of power on both of the AC feeders from the utility company. The IBF can hold power
briefly over a “brownout”, or for orderly shutdown in case of a longer outage. The IBF
provides up to 20 minutes of full power, depending on I/O configuration.
2. One or two Modular Refrigeration Units (MRUs) that are air-cooled by their own internal
cooling fans.
3. The CEC cage, containing up to four books, each with two insulated refrigeration lines to
an MRU.
4. I/O Cage 1, which can house all supported types of channel cards. An I/O cage
accommodates up to 420 ESCON channels or up to 40 channels in the absence of any
other card.
5. Air-moving devices (AMD) providing N+1 cooling for the MBAs, memory, and DCAs.
Z frame
As shown in Figure 2-9 on page 33, the main components in the Z-frame are:
1. Two Internal Battery Features (IBFs) (see IBF in A frame for more information).
2. The Bulk Power Assemblies (BPAs).
3. I/O cage 2 (bottom) and I/O cage 3 (top). Note that both I/O cages are the same as the
one in the A frame, and can house all supported types of channel card.
The Z frame holds no cages, only the bottom cage (I/O cage 2), or both the bottom and top
I/O cages (I/O cage 2 and I/O cage 3).
4. The Service Element (SE) tray, which is located in front of I/O cage 2, contains the two
SEs.
I/O cages
There are 12 STI buses per book to transfer data, with a bi-directional bandwidth of 2.0 GBps
each. An STI is driven off an MBA. There are three MBAs per book, each driving four STIs,
providing an aggregated bandwidth of 24 GBps per book.
The STIs connect to I/O cages that may contain a variety of channel, coupling link,
OSA-Express, and Cryptographic feature cards:
ESCON channels (16 port cards).
FICON channels (FICON or FCP modes, two port cards).
ISC-3 links (up to four coupling links, two links per Daughter Card (ISC-D). Two Daughter
Cards plug into one Mother Card (ISC-M).
Integrated Cluster Bus (ICB) channels, both ICB-2 (333 MBps) and ICB-3 (1 GBps). Both
ICB-2 and ICB-3 (compatibility mode ICBs) require an STI extender card in the I/O cage.
OSA-Express channels:
– OSA-E Gb Ethernet
– Fast Ethernet
– 1000BASE-T Ethernet