Hitachi 9900 User And Reference Manual page 26

Front End: The 9900 front end is entirely resident in the 9900 controller frame and includes
the client-host interface processors (CHIPs) that reside on the channel adapter (CHA or CHT)
boards. The CHIPs control the transfer of data to and from the host processors via the fibre-
channel, ExSA™, and/or FICON™ channel interfaces and to and from cache memory via
independent high-speed paths through the cache switches (CSWs).
Each channel adapter board (CHA or CHT) can contain two or four CHIPs. The 9960
subsystem supports up to eight CHAs for a maximum of 32 host interfaces, and the 9910
subsystem supports up to six CHAs to provide a maximum of 24 host interfaces.
The 9960 controller contains four cache switch (CSW) cards, and the 9910 controller
contains two CSW cards.
Cache memory in the 9960 resides on two or four cards depending on features, and each
cache card is backed up by a separate battery. The 9910 supports two cache cards.
Shared memory resides on the first two cache cards and is provided with its own power
sources and backup batteries. Shared memory also has independent address and data
paths from the channel adapter and disk adapter boards.
Back End: The 9900 back end is controlled by the array control processors (ACPs) that reside
on the disk adapter boards in the 9900 controller frame. The ACPs control the transfer of
data to and from the disk arrays via high-speed fibre (100 MB/sec or 1 Gbps) and then to and
from cache memory via independent high-speed paths through the CSWs.
The disk adapter board (DKA) contains four ACPs. The 9960 subsystem supports up to
eight DKAs for a maximum of 32 ACPs. The 9910 subsystem supports two DKAs for a
maximum of eight ACPs.
The 9960 subsystem (see Figure 2.2) includes the following major components:
One controller frame containing the control and operational components of the
subsystem.
Up to six disk array frames containing the storage components (disk drive arrays) of the
subsystem.
The service processor (SVP) (see section 2.5). The 9900 SVP is located in the controller
frame and can only be used by authorized Hitachi Data Systems personnel.
The Remote Console PC (see section 2.6). The 9900 Remote Console PC can be attached
to multiple 9960 and/or 9910 subsystems via the 9900-internal local-area network (LAN).
The 9910 subsystem (see Figure 2.3) includes the following major components:
One frame containing the controller and disk components of the subsystem.
The service processor (SVP) (see section 2.5). The 9900 SVP is located in the controller
frame and can only be used by authorized Hitachi Data Systems personnel.
The Remote Console PC (see section 2.6). The 9900 Remote Console PC can be attached
to multiple 9960 and/or 9910 subsystems.
12 Chapter 2 Subsystem Architecture and Components