Apple Final Cut Pro 7 - Manual (Page 225)

Parallel ATA disks use 40- or 80-pin-wide ribbon cables to transfer multiple bits of data
simultaneously (in parallel), they have a cable length limit of 18 inches, and they require
five volts of power. Depending on your computer, there may be one or more parallel ATA
(or IDE) controller chips on the motherboard. Each parallel ATA channel on a computer
motherboard supports two channels, so you can connect two disk drives. However, when
both disk drives are connected, they must share the data bandwidth of the connection,
so the data rate can potentially be reduced.
Serial ATA Disks
Serial ATA (SATA) disks are newer than parallel ATA disk drives. The disk drive mechanisms
may be similar, but the interface is significantly different. The serial ATA interface has the
following characteristics:
• Serial data transfer (one bit at a time)
• 150 MB/sec. theoretical data throughput limit
• 7-pin data connection, with cable limit of 1 meter
• Operates with 250 mV
• Only one disk drive allowed per serial ATA controller chip on a computer motherboard,
so disk drives do not have to share data bandwidth
FireWire Disk Drives
Although not recommended for all systems, FireWire disk drives can be effectively used
to capture and edit projects using low data rate video clips, such as those captured using
the DV codec. However, most FireWire disk drives lack the performance of internal Ultra
ATA disk drives or of internal or external SCSI disk drives. For example, a FireWire disk
drive may not be able to support real-time playback with as many simultaneous audio
and video tracks as an internal Ultra ATA disk drive can. This can also affect the number
of simultaneous real-time effects that can be played back.
Keep the following points about FireWire drives in mind:
• FireWire disk drives are not recommended for capturing high data rate material such
as uncompressed SD or HD video.
• Certain DV camcorders cannot be connected to a computer while a FireWire disk drive
is connected simultaneously. In many cases, you can improve performance by installing
a separate FireWire PCI Express card to connect your FireWire drive.
• You may be able to improve performance by reducing the real-time video playback
data rate and the number of real-time audio tracks in the General tab of the User
Preferences window.
• You should never disconnect a FireWire disk drive prior to unmounting it from the
desktop.
225 Chapter 13 Determining Your Hard Disk Storage Options