Specifications

v When you attach a device to the end of your SCSI bus, you must terminate it. If
you attach a device in the middle of a SCSI bus, you must not terminate it.
v Each SCSI bus requires at least one initiator. The SCSI specification requires
initiators to provide TERMPWR to the SCSI bus.
Cable lengths
The ESS requires a total SCSI bus length that is no greater than 25 m (75 ft). The
resulting configuration must meet any cable length limitations that are required by
any attached SCSI device. Use only ESS supported cables that are 10 m (30 ft)
and 20 m (60 ft) in length.
SCSI initiators and I/O queuing
SCSI host adapters support from 1 to 15 initiators on a SCSI bus. The number of
initiators and the number of targets you define on the bus will be less than or equal
to 16. The limit for the number of initiators that perform persistent reservations is
512 node ports.
Connecting the SCSI cables
Perform the following steps to connect the ESS to your host system.
Attention: To avoid static discharge damage when you handle DDMs and other
parts, observe the precautions in “Handling electrostatic discharge-sensitive
components” on page 10.
1. Complete the installation planning and configuration planning tasks outlined in
the ESS Introduction and Planning Guide.
2. Install a SCSI adapter (interface card) in your host system by using the
instructions in your host system documents.
Note: Contact your IBM service support representative (SSR) to install the
6501 adapter on the IBM AS/400 and iSeries. The 6501 adapter is a
feature code.
3. Connect the SCSI cables to your host system.
Attention: Use caution when handling the SCSI cables, especially when
aligning the connectors for plugging. You can damage the cables or plugs. Turn
off the AS/400 or iSeries host before you attach to or move SCSI cables on the
6501 adapter.
4. Have the IBM service support representative attach the SCSI cables to the
ESS.
5. If you are attaching a second host to the same SCSI interface card, ensure that
each host adapter has a unique SCSI ID (address).
Figure 4 on page 10 represents an ESS that is connected to two hosts.
Chapter 1. Introduction 9