Product specifications

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Due to the high data transfer rates associated with digital audio and
video, Avid systems use wide, 68-pin SCSI connections to link the
Avid Media Processor to the media storage drives. There are two types
of wide SCSI connections:
¥ Single-ended SCSI
For linking fewer storage devices close to the Avid Media
Processor.
¥ Differential SCSI
For linking storage devices farther away from the Avid Media
Processor, using storage expanders for connecting more storage
devices, and for higher data rates.
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Single-ended and differential SCSI are incompatible with each
other. Mixing the two interfaces can seriously damage any or all
connected devices due to electrical and cabling incompatibilities.
A single-ended SCSI bus complements each data line with a ground
path connection, so for every line that passes information between the
host and a device, there is one connector that is always at ground
potential.
In contrast, a differential bus has no data ground lines. Instead, each
signal line is complemented by a negative data line. When a signal line
goes high, its complement goes low, and vice versa.
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Single-ended and differential SCSI devices must be attached to the
correct type of single-ended or differential SCSI board. Failure to
install the hardware correctly could cause the system to fail or could
damage the connected devices.
The differences between the two types of SCSI hardware are explained
in the following sections. The installation instructions at the end of this
chapter specify the hardware to use for the storage option.