Parallel ATA vs. SCSI:

PATA drive technology has improved over the years and has replaced SCSI in many applications due to their lower cost and improved performance. PATA technology is designed to be used with short cables (about 17 inches) inside the computer cabinet, while SCSI supports longer cables making it the choice for external storage and for high performance RAID systems. Serial ATA allows for one-meter cables and is
possible to create high-speed external disk arrays.

Parallel ATA (PATA) or what has been called ATA:
If you plan on editing using DV or DVCAM as your source, 7200-RPM PATA Ultra DMA drives offer plenty of bandwidth. There is no need to consider a RAID storage system. A single PATA-133 disk drive connected to an ATA-66 or ATA-100 port will sustain 35 MB/sec reads and high as 45 MB/sec on writes. DV and DVCAM use only 3.6 MB/sec and will run clean with a minimum sustain rate of 7 MB/sec.

Serial ATA (SATA):
What is Serial-ATA (SATA) and why was it developed? SATA is an evolutionary replacement for the existing Parallel-ATA (PATA) data storage interface. SATA is scalable and allows for future enhancements. SATA is a drop-in solution in that it is compatible with today’s software, which will run without modification. It provides cables that are simpler to route and install, smaller cable connectors, and lower voltages not possible with PATA.

Will there still be PATA when SATA is readily available?
There will be a window of time where both PATA and SATA will be available. Many expect that within a couple of years that SATA will dominate. Apple’s G5 computers come with 2 SATA ports. Some PC motherboards come with both PATA and SATA ports. SATA PCI cards are available now with more to come includes those with up to four ports.

What are the benefits of SATA?
End users will benefit with easy upgrades to their storage. Configuration of SATA devices will be much simpler, with no requirements of jumper and settings. Other considerations include:
A 150 MB/sec interface rate (not to be confused with the data rate of a single drive)
Enhanced data reliability
Longer and thinner cables – up to one meter or about 3 feet
Snap-in like connectors
No master/slave jumpers to set
Master only will improve performance of striped hard disk drive pairs
Latency more like that of SCSI thus RAID-0 to be much faster than PATA
What is the cost to implement SATA in a system?
The cost of SATA will start out somewhat more expensive than PATA but will rapidly drop to the same cost as PATA.

Beyond hard disks, will SATA be used on, optical drives, DVD, and ZIP drives?
SATA supports all ATA and ATAPI devices, including CDs, DVDs, tapes devices, high capacity removable devices, zip drives, and CDRWs.

What are some compelling reasons why SATA is viable?


Price: SATA was created, with desktop prices in mind, as a replacement for PATA. Initial hard disk drives are expected to be priced competitively for the desktop.
Cabling: SATA employs a thin, point-to-point connection, which allows for easy cable routing within a system. This avoids master/slave, "daisy-chaining", and termination issues. Also, better airflow can be realized compared to systems with wider ribbon cables.
Performance: The first SATA bus technology can deliver as much as 1.5 Gbps (150 MB/sec) of performance to each drive within a disk drive array and migrating to 3.0 gigabits per second (300 MB/s), then to 6.0 gigabits per second (600 MB/s).
This roadmap supports up to 10 years of storage evolution. The maximum rate of PATA drives today is about 72 MB/sec. But remember this is the bus rate and should not be confused with the data rate of a single PATA or SATA disk drive. The choke point remains the disk drive not the bus. A single PATA or SATA drive will remain about 35 to 45 MB/sec. With SATA multiple disk drives can be striped with performance near that of SCSI.

So you see, 35 to 45 MB/sec from current PATA or SATA technology is more than enough for DV and DVCAM. However, single PATA or SATA disk drives do not produce high enough sustained rates for uncompressed SD video. In the mirror faced G4 computers that have 3 ATA ports one can add 4 additional PATA drives that can be stripped as RAID-0 that will produce sustained data rates high enough for uncompressed SD video. In this case it is best to move the boot drive to the lower optical drive and connect it to a PCI ATA card. In the new G5’s there is only room for two SATA drives (one for boot and one for data) thus if more is need one must go externally.