CanadaRAM
Wednesday 08 December 2004 à 07:07
QUOTE (kd_rome @ Dec 6 2004, 16:36)
I was cecking this page
http://www.barefeats.com/fire45.htmlbut I can't understand something: what does Dual 2 channel and Dual 1 channel mean?
Two Channel vs One channel refers to Firewire ports and whether the machine has a separate Firewire interface chip for each port, or whether the 2 ports are simply attached to a single interface chip.
Think of a garden hose. If you take one hose and put a Y-splitter on the nozzle end, you have two "ports" but only one "channel" -- the same amount of water will come out, just 1/2 on each nozzle.
Now think of two different hoses connected to different taps, each one can deliver the full volume to its output (Port) This is two channel, much wetter (er.. faster).
This is also the reason why Firewire audio interfaces perform less well when you daisy-chain a hard drive off them; the drive data is contending with the audio data in the same hose (channel).
Setting up two-channel Firewire on most Macs requires installing a PCI Firewire card, or a PCMCIA Firewire interface on a Powerbook.
G5's have two channels, one for FW400 and one for FW800, so put the audio interface on the FW400 and the hard drive on the FW800. Two FW800 channels still requires a card.
A couple of the high end G4 towers had two FW400 channels, most didn't.
Barefeats found that when you use two channel Firewire the performance of a dual-drive setup is much better, simply because all the data is not trying to push through a single channel. Their reference to "D2 Dual 1 Channel" refers to the drive they were testing; the "LaCie D2 Dual" drive which has 2 drives in one case. They tested this drive with both 1-channel and 2-channel connections.
Ourmanflinty: Barefeats showed that the same Parallel IDE 7200 RPM Hitachi drive had significantly better throughput on Firewire 800 - about 50% better in fact - so I don't believe that Firewire 400 is higher in real-world throughput than the drive itself.
http://www.barefeats.com/fire35.htmlThanks
Trevor
CanadaRAM.com[/B]