What is firewire

Asks manhattan

A. Firewire (also known as standard IEEE 1394) is a high performance serial bus, developed by Apple Computers, to connect multimedia devices to your computer. It works on one single plug connection to which up to 63 devices can be attached with data transfer speeds of up to 400Mbps.

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Firewire offers its service in isochronous or real time (it appears to work in real time in its presentation to the user, but in reality it operates over pre-set times to avoid the need for buffering)�- so there is no time delay and because it operates over a wide bandwidth it can support multimedia applications like audio, video and imaging programmes seamlessly.

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Its major benefits are that:

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* it is amazingly fast at 400Mbps

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* it supports up to 63 devices at once using ordinary cable - which use snap connections so you don't need device IDs, jumpers, DIP switches, screws, latches or terminators.

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* it is hot pluggable - so you don't have to switch off other applications to run it and you don't have to shut down and restart your computer.

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* It is scalable � the 1394 standard defines 100, 200, and 400Mbps devices and can support the multiple speeds on a single bus.

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* It supports asynchronous and isochronous data transfer. Asynchronous transfer is important and appropriate for traditional computers with memory-mapped, load and store applications. Whereas isochronous data transfer provides guaranteed data transport at a pre-determined rate - important for multimedia applications where uninterrupted transport of time-critical data and just-in-time delivery reduce the need for costly buffering.

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Q. In reality, what does that mean I can plug into my computer

A. It means you can plug in most digital consumer items like DVDs, digital cameras, digital camcorders, digital video tapes, set top boxes and digital music systems - and because it has a hot plug or plug and play function (depending on what version you have) it means that you can just plug it into your PC without having to turn it off first and then restart it.

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Q. How near does a digital device have to be from the PC or bus socket to work

A. It has to be within 4.5 metres.

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Q. Is Firewire similar to a USB port or a SCSI connection

A. In principle it is, but with a much bigger capability - and in fact Firewire and other IEEE 1394 standard products are set to replace them. A USB can achieve data transfer rates of 12Mbps and it can hot plug; and SCSI can achieve rates of up to 40Mbps and it requires address pre-assignment.

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Q. Is Firewire only used on Apple Macs

A. It was originally, but it is now supported by companies like AT&T, IBM, Philips, Texas Instruments, Adaptec, Microsoft, Sony, Canon, JVC and Kodak.

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Q. Does Firewire come as a standard feature in all Apple Macs

A. It is now integrated into most of them (basically all new Apple computers) - it is standard in all Power Mac G4 and G3 computers, current versions of the PowerBook and iBook, and all iMac DV computers including the iMac DV Special Edition.

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Q. When was Firewire invented

A. Apple invented it in the mid-1990s and it became a standard in 1996 although not in the polished and fast version that you find today. The current version is Firewire 2.7.

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More information on Firewire is available from Apple at www.apple.com/firewire.

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By Karen Anderson