IBM 7133 Series, Service Manual

Page: 68 / 230

|
Multiple-Unit Configurations for Models 020 and 600
| An SSA subsystem can include disk drive modules that are installed in more than one
| 7133. You can connect up to 48 disk drive modules in one loop, and up to 96 disk drive
| modules to one adapter.
| In larger subsystems, unless the work load of the system has special requirements, best
| performance is obtained if you connect equal numbers of disk drive modules to the loops
| that are available. In the following example, 32 disk drive modules are connected to an
| SSA adapter. They can all be connected in one loop, but for better performance and
| better serviceability, it is recommended that the disk drive modules be connected in two
| loops, each of which is connected to a separate pair of connectors on the SSA adapter.
7133 unit 1
4
8
1
12
4 3 2 1 5 6 7 8
9 10 11 12 13 14 15 16
13
5
9
16
U s in g s y s te m
A1 A2 B1 B2
7133 unit 2
4
8
1
12
4 3 2 1 5 6 7 8
9 10 11 12 13 14 15 16
13
5
9
16
| The cables are described in “SSA Cables” on page 1-43. The internal connections of
| Model 020 are shown in “Model 020 Internal Connections” on page 1-18; those of Model
| 600 are shown in “Model 600 Internal Connections” on page 1-21.
| For information about the rules for SSA loops, see the “Rules for SSA Loops” on
| page 1-42.
1-54
7133 Service Guide