Spectra Logic 10000 manual Determining Scsi ID Usage

Chapter 2. Preparing the Host System

Selecting a SCSI Bus for the Library (SCSI Libraries Only)

The single-ended/low-voltage differential (SE/LVD) library operates in either single- ended or low-voltage differential SCSI mode, depending on the type of bus that is attached. When attached to a single-ended SCSI adapter, it will operate within the maximum specifications for that bus type.

Note: The entire bus (including host bus adapter, devices and termination) must be configured for LVD operation in order to operate in LVD mode. Attaching any single-ended SCSI device to an LVD bus renders the entire bus (and all attached devices) subject to the maximum specification requirements for single-ended SCSI (including maximum cable lengths).

The terminator shipped with the SE/LVD library can function in either mode. To check the mode in which your library is operating, look at the library terminator and the terminator’s light-emitting diode (LED). The top of the terminator lists the color of the LED for each mode.

Note: The HVD library includes an active HVD terminator.

SCSI specifications for LVD, SE, and HVD modes are shown in this table:

SCSI Specifications	LVD Mode	SE Mode	HVD Mode
SCSI Bus Width	16 bits	16 bits	16 bits
Maximum Bus Speed	80 MB/sec	40 MB/sec	40 MB/sec
Maximum Bus Cable Lengths	12 metersa	1.5 metersa	25 metersa

aMaximum cable length requirements include the internal cabling for each device. (The library contains 60 centimeters [24 inches] of cabling inside the library.)

Determining SCSI ID Usage

Each device on the SCSI bus to which the library is attached must have its own SCSI ID. Examine your host system and attached devices to determine which SCSI IDs are

22