05-06-2012, 04:31 PM
FIREWIRE
52647437-Fire-Wire.pdf (Size: 285.88 KB / Downloads: 14)
INTRODUCTION
What is FireWire?
The FireWire is one of the fastest peripheral standards ever developed, which makes it great
for use with multimedia peripherals such as digital video cameras and other high-speed devices
like the latest hard disk drives and printers. It was introduced as a successor to the SCSI.
FireWire is integrated into Power Macs, iMacs, eMacs, MacBooks, MacBook Pros, and the
iPod. FireWire ports were also integrated into many other computer products dating back to the
Power Macintosh G3 "Blue & White" computers. All these machines include FireWire ports that
operate at up to 400 megabits per second and the latest machines include FireWire ports that
support 1394b and operate at up to 800 megabits per second.
History and development
Before FireWire and USB appeared, external devices were typically connected to a
computer using serial and parallel ports. But those connections had many limitations: data
transfer rates were sluggish, devices couldn't be unplugged without causing your computer to
crash, you couldn't easily swap multiple devices on the same port, and so on.
In fact FireWire was introduced as a successor to the SCSI. So let us have a look on the
SCSI first. Small Computer System Interface, or SCSI (pronounced skuh-zee), is a set of
standards for physically connecting and transferring data between computers and peripheral
devices. The SCSI standards define commands, protocols, and electrical and optical interfaces.
IEEE 1394 Capabilities
The IEEE 1394 standard defines a high speed serial interface that can be used to connect
peripheral devices, for example, printers, scanners, and cameras, to your computer. Some
common features of the IEEE 1394 standard are:
· A simple plug and socket connection. This connection is visually similar to universal
serial bus (USB) connections, although USB and IEEE 1394 are not compatible.
· The capacity to have up to 63 devices connected serially (in series) to a single port.
· Data transfer speeds of up to the rate of 400 megabytes (MB) per second. (The
maximum speed is presently 200 MB per second.)
Differences between FireWire 400 and FireWire 800
With the development of FireWire 800, the question on everyone’s mind is, what is going
to happen to your legacy devices? Existing peripherals and devices are going to continue
to operate. The performance will remain the same for your legacy FireWire devices
operating at the original FireWire 400 speed.
Essentially, the main difference between FireWire 800 and FireWire 400 can be summed
up in one word – speed. FireWire 800 offers impressive results, with speeds up to
100MB/s, though current drive technology limits this to 55MB/s (maximum sustained
throughput) for a single drive, and up to 100MB/s (maximum sustained throughput) per
bus in RAID 0 configurations.
