Apple Final Cut Express HD - Manual (Page 159)

Chapter 12 Determining Your Hard Disk Storage Options 159
III
SCSI Disk Drives
SCSI disk drives are among the fastest drives available. SCSI (Small Computer Systems
Interface) technology has been implemented in various ways over the years, with each
successive generation achieving better performance. Currently, the two fastest 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 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.
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, including scanners and
removable storage media. You should not connect such devices to your high-
performance SCSI interface.
Computer
SCSI
card
SCSI cable SCSI cable
SCSI terminator
SCSI cable