multipule fire wire cards???

[jan tanjo]

Hi

How many fire wire cards can you have on one machine without XP questioning your sanity? (I'd like to install 2, maybe 3)

[Variable]

Probably as many you have pci slots.Why would you need three? Just curious..

[jan tanjo]

Thanks

I don't really want to daisy chain hard drives and cameras etc

[Budfred]

I think you can get firewire cards with up to about 6 ports. I have also seen cards that have a few firewire and a few USB 2.0 ports...

[saphalline]

You don't want to daisy-chain them in terms of all the physical cables? Or you don't want to daisy-chain them in terms of sharing bandwidth?

For the first one, I recommend a powered firewire hub (ie it plugs into the wall outlet). That will keep those cables in check!

For the second one, PCI cards are not the answer. the PCI bus is one big bus with a 133MB/s bandwidth. That's 133MB/s for all the PCI slots put together! :eek: So if you have one firewire hard drive per PCI card, that's 2-3 hard drives all sharing 133MB/s at once.

44-66MB/s per hard drive isn't bad, but the firewire spec states only 50MB/s per channel. One PCI card usually has one channel, so it will never get above 50MB/s. If you're OK with all of this, go ahead, but I prefer busses hooked directly to the chipset.

Of course, I just dislike the PCI bus in general, so... :rolleyes:

[Variable]

Yea, thats what I thought maybe you were thinking. Like the other fella said, your bandwidth is limited anyway. Adding multiple cards does nothing but eat up multiple pci slots. The hub idea sounds like the ticket. One device you can plug em all into.

[jan tanjo]

thanks saphalline, that is something I did not know.

My concern is, lets say I have the my hard drive connected to the fire wire card, my camera connected to the hard drive, that would mean the data is coming from the camera then going through hard drive (not literally) to the fire wire card and then back to the hard drive.

Now I think of the data path like a single lane highway, (it's the audio staging in me) video is pretty instense, the cable between the firewire card and the hard drive is going to have a lot of traffic going both ways

To get the best quality and the fewest dropped frames I don't want that, so my theory is 2 cards, one for data coming in and one for data going out..... or am I just wacked out on lemon fresh pledge fumes???

[saphalline]

Well, your theory is sound, but again it breaks down at the PCI bus. Even if the PCI cards act as a one-way transfer so-to-speak, all that data is still going to collide in the PCI bus. Remember, all the PCI cards share one "wire", so it's more like you're delaying the inevitable.

Not that having more than one PCI card wouldn't help. It probably would in most conditions. But a powered hub would do the same thing. Basically you want data-hungry devices like hard drives by themselves (ie no daisy-chain going thru them) so just keep them at the end of the chain. That's as close as you can get to keeping their wires "clean".

The other reason you want data-hungry devices on their own chain is because of signal integrity. This is something that's practical more than technical. Even though the Firewire bus spec is very specific about the device-side controllers, there's still a lot of quality issues there. A cheap device simply won't pass on data as well as an expensive one. Also, some devices are tuned for latency vs sustained bandwidth. So keep the wimpy, cheapie devices away from your hard drive(s) and they'll be happy.

[jan tanjo]

OK, If I can rephrase, The "buttom" of the data stream "V" is at the "front" of the PCI bus.

In other words the data comes in the firewire card in slot 2, passes slot 1 goes to the front of the bus, returns past slot 1 out slot 2 through the firewire card to where ever.

If that is the case, assuming that you mobo is of quality, what determines the quality of your firewire card?

Also, from what I'm hearing, would not a card with 2 ports be more "stable" than one with four, your are not splitting the data stream up so much, or is the data stream split as more devices demand attention?

[saphalline]

Well, there is no "front" of any bus, but the main point is that firewire devices will be slower if you use more than one at a time.

The main factor in determining the quality of any hardware component is the manufacturer. I would sooner buy a firewire card made by Asus than by Ahanix, simply because Asus makes better stuff! :D Stick to manufacturers that you recognize as making quality stuff and you're likely to get a quality product.