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-   -   ADVC110, MacbookPro, Firewire drive (http://forum.grassvalley.com/forum/showthread.php?t=4690)

digitaldave1984 02-12-2008 02:21 AM

ADVC110, MacbookPro, Firewire drive
 
Getting ready to order the ADVC110 to use with my laptop that has a single firewire400 port. I currently have a fw400 external drive and an M-Audio FW410 connected. I don't see that the ADVC110 has a fw pass-thru, so it would connect at the end of the cabling.
Can I expect a problem with this scenario?
In addition, naturally() I want the capture to go to the external FW drive.
Murphys law tells me I might have an issue or 2 to resolve, usually solved by time, frustration and money.
So, from those of you that have already gone down this road, will this work, and if not, what advice can I get to make this work?
(I have scanned all the messages in this forum and have not found the answer)

TIA
Dave Harding

GrassValley_KH 02-12-2008 06:28 PM

Sorry, but it's not really a good idea to be pairing, daisy-chaining or otherwise splitting FireWire with an ADVC110 and other devices.

The best way to use it is to isolate the ADVC110 unit on its own FireWire connection. Since your laptop only has one port, it'll mean unplugging the other two devices. It will save you a lot of headaches in the long run.

digitaldave1984 02-12-2008 08:58 PM

I thought that would be the case. Anyone have a recommendation for an ExpressCard/34 firewire adapter?

tizoast 02-12-2008 09:49 PM

Quote:

Originally Posted by GrassValley_KH (Post 28399)
Sorry, but it's not really a good idea to be pairing, daisy-chaining or otherwise splitting FireWire with an ADVC110 and other devices.

Why does every FireWire doc I read say that it's OK to chain up to 64 devices together?

GrassValley_BH 02-12-2008 10:15 PM

Quote:

Originally Posted by tizoast (Post 28437)
Why does every FireWire doc I read say that it's OK to chain up to 64 devices together?

Because they didn't take streaming video into account there...

Sure, you can chain a whole bunch of FireWire devices together, heck I've had 8 FireWire-IDE bridge boards daisy-chained. But it didn't work well... Eventually I ditched that setup.

Anyway, the problem is that DV transfer requires a constant 25 Mbps bandwidth. It can't be 40 Mbps now and 10 Mbps next. It needs a steady 25 Mbps transfer so every frame gets to the destination on-time. Unlike Internet streaming video, the receiving device can't buffer the data and even if it could, if the bandwidth was not steady at some point it would still run out of data.

When you daisy-chain high-bandwidth devices like hard drives in the chain, you can end up with a situation where a few devices "hog" the bus bandwidth and interrupt the steady flow of DV data. SCSI used to have a similar problem back in the day...

tizoast 02-13-2008 01:37 AM

That certainly makes sense. Thanks for the explanation.


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