AJA io hd, Installation And Operation Manual

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6
Understanding
Disk Storage
Methods The Io HD with an Apple Mac Pro or Apple MacBook Pro and Final Cut Pro 6,
along with a suitable storage system, offer an unprecedented level of features and
performance for all audio/video production applications. However, to ensure
performance and quality, the disk storage system used with the Mac Pro or
MacBook Pro must be able to meet the demands of storing realtime uncompressed
SD media and ProRes 422 HD media. There are a variety of system configurations
and peripherals that can provide this level of performance.
For uncompressed SD, AJA recommends that at a minimum, the disk storage
system must be able to provide and maintain a consistent 50 MB/sec transfer rate
from the Apple computer to disk (read/write). There are a variety of system
configurations and peripherals that can provide this level of performance.
For Apple ProRes 422, AJA recommends that at a minimum, the disk storage
system must be able to provide and maintain a consistent 40 MB/sec transfer rate
from the Apple computer to disk (read/write) for normal quality. For HQ quality
Apple ProRes 422, we recommend at least a 50 MB/sec transfer rate. There are a
variety of system configurations and peripherals that can provide these levels of
performance.
Io HD users wishing to configure storage for a system should also be aware that raw
benchmark numbers alone do not necessarily reflect the performance of a drive
solution. Other factors, such as drive seek time and controller cache can also affect
performance.
FireWire drive solutions are not supported in use with AJA Io HD when plugged
into the same system bus. Since Io HD connects to the host Mac Pro or MacBook
Pro via FireWire 800 and uses the FireWire bus bandwidth extensively, that same
Apple system bus cannot also be used for storage—at the same time. You can
however attach and use FireWire drives on the computer whenever the Io HD is not
powered or attached to the system. To use FireWire storage and the Io HD at the
same time, you can add a FireWire HBA (host bus adapter) card to the computer
(or ExpressCard/34 FireWire card if using a MacBook Pro) and then connect
storage drives to this separate FireWire bus.
About RAIDs
Redundant Array of Independent Disks, or RAID, is a group of hard drives that
appears to the host Mac as a single high-speed storage unit. RAID systems enable
you to increase storage capacity and get the performance, reliability, and data
protection needed for video production that is not possible when using a single hard
drive. RAID drives inside the array operate simultaneously, increasing overall
throughput. RAID technology is comprised of these techniques (some or all):
•
Striping data across multiple drives for storage performance (RAID 0).
•
Mirroring for redundancy (RAID 1).
•
Parity for data protection (RAID 5 [plus other types]).
Most RAID configurations, or RAID levels, combine these to provide a balance of
protection and performance.