Vela 2000-0600, Installation And User Manual

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Chapter 1 — Getting Started 11
Decoder Installation
The SCSI Interface
The Vela CineCast HD decoder connects to the host system through a Small
Computer Systems Interface (SCSI) interface. This interface conforms to the
following ANSI standards, except as detailed in this specification. The type of
interface is Low Voltage Differential Signal (LVDS) Ultra-2 (Fast-40), which is
compatible with single-ended (SE) Ultra (Fast-20) SCSI.
American National Standards Institute SCSI Standards
SCSI-3 Architectural Model (SAM) X.3.270:1996
SCSI-3 Interlocked Protocol (SIP) X.3.292:1997
SCSI-3 Primary Commands (SPC) X.3.301:1997
SCSI-3 Parallel Interface (SPI) X.3.253:1995
SCSI-3 Parallel Interface-2 (SPI-2) X.3.302:1999
SCSI-3 Fast-20 Parallel Interface (Fast-20) X.3.277:1996
SCSI IDs
Typically, each device on a SCSI bus, including the host adapter, must have a
unique SCSI ID. The SCSI ID serves two purposes:
• It uniquely defines each SCSI device on the bus.
• It determines the device’s priority on the bus during arbitration for the bus.
Setting the Decoder’s SCSI ID
The SCSI ID of the CineCast HD decoder is set via the SCSI ID selector switch
located on the rear of the board or on the rear panel of HD/1 and HD/2 models. It
should be noted that ID7 is usually reserved for the SCSI initiator (host adapter).
On HD/2 decoders, a unique ID should be set for each of the two boards
Priority in Arbitrating For the Bus
• Normally, the SCSI initiator (host adapter) is set for SCSI ID 7, which is the
highest priority.
• Each SCSI device on the bus must have a unique SCSI ID.
• Not all host adapters support SCSI IDs 8–15.
• Some host adapters and operating systems have further restrictions on SCSI
IDs for hard disk, CD-ROMs, and tape drives.
• Operating systems and SCSI device drivers may restrict the use of SCSI IDs
to SCSI IDs 0 through 7 only.