Apple Final Cut Pro 7 - Manual (Page 226)

SCSI Disk Drives
Small Computer System Interface (SCSI) disk drives used to be among the fastest drives
available, although newer computers may no longer provide SCSI ports. Although no
longer highly popular, SCSI technology has been implemented in various ways over the
years, with each successive generation achieving better performance. Two fast SCSI
standards for video capture and playback are:
• Ultra2 LVD (Low Voltage Differential) SCSI: Ultra2 LVD SCSI disk drives offer fast enough
performance to capture and output video at high data rates when a single disk is
formatted as a single volume (as opposed to formatting several disks together as a disk
array).
• Ultra320 and Ultra160 SCSI: These are faster than Ultra2 LVD SCSI disks.
SCSI disks can be installed internally or connected externally. Many users prefer external
SCSI disk drives because they’re easier to move and they stay cooler. If your computer
didn’t come with a preinstalled Ultra2 LVD, Ultra160, or Ultra320 SCSI disk drive, you need
to install a SCSI card in a PCI Express slot so you can connect a SCSI disk drive externally.
A SCSI card allows you to connect up to 15 SCSI disk drives in a daisy chain, with each
disk drive connected to the one before it and the last terminated. (Some SCSI cards
support more than one channel; multiple-channel cards support 15 SCSI disks per channel.)
Use high-quality, shielded cables to prevent data errors. These cables should be as short
as possible (3 feet or less); longer cables can cause problems. You must use an active
terminator on the last disk for reliable performance.
Note: Active terminators have an indicator light that goes on when the SCSI chain is
powered.
SCSI cable
Computer
SCSI
card
SCSI cable SCSI cable
SCSI terminator
All devices on a SCSI chain run at the speed of the slowest device. To achieve a high level
of performance, connect only Ultra2 or faster SCSI disk drives to your SCSI interface card.
Otherwise, you may impede performance and get dropped frames during capture or
playback.
Note: Many kinds of SCSI devices are slower than Ultra2 devices, including scanners and
removable storage media. You should not connect such devices to your high-performance
SCSI interface.
226 Chapter 13 Determining Your Hard Disk Storage Options