Laptop firewire conection - confused.

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robo
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Joined: Aug 15 2000

I've just managed to totally confuse myself over the right and wrong way to connect devices using firewire. On another forum site the question arose as to adding an external hard drive - firewire or USB, the answers (for editing) were generally given as firewire (USB being ok for basic data transfer but not for video work)

The question then came back as to how can you connect both deck and hard drive when you only have one firewire port? Now I jumped straight in and said 'just daisychain both to the single port'. The replies from many other came back to say you can't do that without problems with dropped frames etc. So now I'm confused as I always thought that you could daisychain deck and hard drive - if not then what is the best way to connect the two devices especially in the case of a laptop

robo

PaulD
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Joined: Aug 31 2002

Hi
Yes, you daisychain, putting the hard drive(s) nearest the computer, because some camcorders can slow the channel down below the nominal 400Mb/s that a good drive will work at.

But, beware that not all anonymous Tiawanese FW drive bridge boards are as fast as the best, so hard drive performance needs to be checked if using an external FW case not from one of the big manufacturers (many are OK but lots are not).

An alternative is to put a PCMCIA FireWire 400 or 800 card into a laptop computer's slot, to give you another channel if there is an inbuilt one.

Alan Roberts
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Joined: May 3 1999

I often do it that way. I use ADS Pyro enclosures, 1394-connected to the laptop, and the camcorder daisy chained from it. It works for my old Panasonic DX100, and for my shiny new HDV A1. Firewire is fast enough to manage it, and can sustain the speed. I almost always use the external drive for video storage, so, during capture, the cameraq delivers data to the computer, which then sends it to the external drive down the same wire. I've nmever loist a frame doing this. i also use a LaCie external, but that diesn't have a 1394 daisy-chain connection, so I used USB2 for it, and the firewire port on the laptop for the camera. That workls 100% as well.

One thing I've foudn though, that's a pain, is that the LaCie box powers itself up only when it sees power down the cable. So the 4-pin 1394 connector on the laptop won't fire it up, it has to be USB2. To make matters worse, it won't fire up if it's daisy-chained from the ADS boxes either. Nevertheless, I've had 2 ADS enclosures and a camera all daisy-chained together, and it all works. No problem.

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

PaulD
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Joined: Aug 31 2002
Alan Roberts wrote:
One thing I've found though, that's a pain, is that the LaCie box powers itself up only when it sees power down the cable. So the 4-pin 1394 connector on the laptop won't fire it up...

Hi
Does it have a blue power indicator button to hold in to power it up off its power supply?

Alan Roberts
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Joined: May 3 1999

Coo, it's got a blue lamp that lights up whenh it runs, but I hadn't realised it's a switch as well. I must give that a try.

Well, well, well. So that's it. Thanks Paul, ,you learn something every day in this game :)

Get my test cards document, and cards for 625, 525, 720 and 1080. Thanks to Gavin Gration for hosting them.
Camera settings documents are held by Daniel Browning and at the EBU
My book, 'Circles of Confusion' is available here.
Also EBU Tech.3335 tells how to test cameras, and R.118 tells how to use the results.

robo
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Joined: Aug 15 2000

Many thanks to both Alan and Paul, I was sure that I'd got it right in my own head. Don't get me wrong, I wasn't going on a 'I was right so na na na na na' crusade, it's just that I haven't, as yet, done a long project with the daisychain set up and had a horrible feeling I may have been entering a long dark tunnel of dispair (going by the postings on the other forum).

By the way, thanks for the tip about the Lacie drive as I'm about to get one myself - so that just saved another posting!!

robo