IBM eServer xSeries 226Type 8648, Руководство по установке опций

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different devices on the same SCSI channel do not attempt to transfer data
simultaneously. SCSI devices that are connected to different SCSI channels can
have duplicate SCSI IDs.
The hot-swap-drive backplane controls the SCSI IDs for the internal hot-swap drive
bays. However, when you attach an external SCSI device to an optional SCSI
adapter, you must set a unique ID for the device. See the information that comes
with the device for instructions to set its SCSI ID.
You can attach external SCSI devices using an optional SCSI adapter. To select
and order the correct adapter for use with external devices, contact your IBM
marketing representative or authorized reseller. When using an optional SCSI
adapter, you must also connect the SCSI adapter to the SCSI LED connector on
the system board to receive an indication of SCSI hard disk drive activity.
Note: On server models that support SATA hard disk drives, you can attach only an
external SCSI tape drive to an optional SCSI adapter.
See “System-board internal connectors” on page 3 for the location of the SCSI
connectors. For information about the maximum length of SCSI cable, see the
American National Standards Institute (ANSI) SCSI standards on the ANSI Web site
at http://www.ansi.org/. Adhering to these standards will help to ensure that your
server operates correctly.
Universal Serial Bus connectors
Use a Universal Serial Bus (USB) 2.0 connector to connect a USB device. USB 2.0
technology transfers data at up to 480 Mb per second (Mbps) with a maximum of
127 devices and a maximum signal distance of 5 meters (16 ft) per segment (if the
device that is attached to the server is a USB 2.0 device). If multiple USB devices
are attached to the server, the USB hub must be 2.0; otherwise, all USB 2.0
devices will transfer data at 12 Mbps. Using Plug and Play technology, USB devices
are configured automatically. The following illustration shows a USB connector.
1 4
Use a 4-pin cable to connect a device to a USB connector. If you need to connect
more USB devices than the server has USB connectors for, use a USB hub to
connect additional devices.
If you connect a PS/2 (non-USB) keyboard to the keyboard connector, USB ports
and devices are disabled during POST.
If you connect a USB keyboard that has a mouse port, the keyboard emulates a
mouse, and you cannot disable the mouse settings in the Configuration/Setup Utility
program.
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xSeries 226 Type 8648: Option Installation Guide