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Topic: Firewire Guru's ... |
James Quackenbush
From:
Pomona, New York, USA
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Posted 15 Sep 2008 5:19 am |
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I recently bought an I-mac which I'm loving BTW ....Very fast and fun to use ...
The I-Mac has 2 Firewire ports ....It has a Firewlre 400 port, and also has a Firewire 800 portl, but they are on the same bus ..... I know if you daisy chain Firewire devices that the first device in the chain dictates what the other devices will be sent ....For example if I have 2 devices daisy chained to a Firewire 400 port and the first device is a Firewire 200 MPS device that the 2nd device will also receive only 200 MPS even though the Firewire port on the computer is a Firewire 400 ......My question is this
Since my I-mac has 2 Firewire ports ( 1-400, and 1-800 ) , and I want to put an audio interface on the FW400 port, and I want to put an external hard drive on the FW800 port , will they work correctly even though they are on the same bus ? ....Will the Fw800 port actually have use of the FW800 speed, or will it get knocked down to FW400 speed because I have the audio interface plugged in and IT runs at FW400 speed ??.....Thanks to all for their time ...Sincerely, JIm |
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Jack Stoner
From:
Kansas City, MO
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Posted 15 Sep 2008 5:38 am
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| HERE is the standards for IEEE 1394. In the "bowels" of this document is probably your answer. |
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James Quackenbush
From:
Pomona, New York, USA
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Posted 15 Sep 2008 8:09 am
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Jack,
Thanks for the complete encyclopedia on Firewire.... I think you are giving me more credit than I should be entitled to ..... I will read all this information that you sent me when I'm in a rocking chair ....In the mean time, I will wait for a simple answer ....I do appreciate you sending me this info though .... It looks very complete .... Sincerely, Jim |
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Wiz Feinberg
From:
Mid-Michigan, USA
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Posted 15 Sep 2008 8:22 am
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James;
Since the two Firewire ports have different maximum speed ratings they are not on the same chipset. What happens in Dodge stays in Dodge. Activity on the FW400 output is fed from a separate driver chip than the FW800 output. They are not simply paralleled; they are electronically isolated.
The actual bus that feeds the Firewire chipsets would be rated at the highest level; in your case 800 mbps. A load on the 400 set will not normally impact the other chip. The outputs are buffered against such load effects. Since I'm not Tron I don't know any more specifics about the way this is implemented.
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James Quackenbush
From:
Pomona, New York, USA
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Posted 15 Sep 2008 9:19 am
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Wiz,
Thanks for the reply ...The engine in my particular I-mac is an Intel Dual Core...It's the 3.06 model so I guess PC guys can also relate ....I guess however it goes down , I still have to have an external h.d. and I still have to have an audio interface , so if I have less of a track count , so be it .... I bought this computer fo an easier, cheaper, simpler, setup rather than going with all the PCI slot setup that I have had in the past ... I use a Metric Halo ULN-2 pre which I really like ....It's a firewire setup ...Simple , to the point, and very clean with many features ....Plenty of gain for ribbon mic's .....Thanks for the info ...Much appreciated ...Sincerely, Jim |
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