IBM RS/6000 manual Data, All Devices That Are Attached, Adapter Card Are Connected Thro Links

Loops

and

Data

Paths

All

devices

that

are

attached

to

an

SSA

adapter

card

are

connected

thro

links. The

SSA

links are configured as loops. Data and commands to

a

particul

device

pass

through

all

other

devices

on

the

link

between

the

adapter a

device.

Data can

travel

in either direction around a

loop. The

adapter

can, ther

the

disk

drive

modules

through

two

data

paths. The using system

cannot

de

which

data

path

is

being used.

If

a

disk

drive module fails, or is turned off, the loop is

broken,

and

paths

to

a

particular

module

is

no

longer

available. The

disk drive

modules

loop continue to

work,

but an

error

is

reported to

the

using

system.

The following

diagram shows that the

disk drive module in slot 3 has faile

drive modules in slots 1 and

2

can

communicate

with

the

using

system

only

connector A1

of

the

SSA

adapter.

The

disk drive

modules

in slots 4, 5,

and

communicate only

through

connector

A2

of

the SSA

adapter.

7-28RS/6000 Enterprise Server Model H Series User's Guide