IBM 7133 Series Service Manual

| Cable Configurations for Models 020 and 600| In the diagrams, the SSA connectors are numbered. These connector numbers match| those shown in “Model 020 Internal Connections” on page 1-18 and “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.| Simplest Configuration for Models 020 and 600| A 7133 Model 020 or Model 600 that is in base configuration includes four disk drive| modules. These modules are installed in the left-hand four slots at the front of the 7133.| The other 12 disk drive slots contain dummy disk drive modules. The disk drive modules| are linked in groups of four. Each group of four modules is linked to two external SSA| connectors.| In the simplest configuration, the SSA loop is completed by connecting these two SSA| connectors to one of the two pairs of connectors on an SSA adapter card in the using| system:7133 unit458911612134 3 2 1Using systemA1 A2 B1 B2| All Models 020 and 600 have three fan-and-power supply assemblies, which provide| redundant power and cooling to all the disk drive modules.| No improvement in performance is gained if the disk drive modules are moved to other| slots and connected in more than one loop.| 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.Chapter 1. Reference Information 1-51