Firewire or USB 2.0?

MichaelS wrote on 10/12/2004, 8:26 PM
I hope someone can save me some time. Tomorrow, I 've got to load several hours of DV onto a ADS Dual Link Hard Drive using a laptop. The laptop has only one (1) firewire port.

Can the Pyro handle video capture via USB 2.0, or should I get a firewire PC Card to output to the drive. The drive is a WD 250g 7200 RPM.

I'm assuming that "daisey chaining" the firewire is a bad idea.

Thanks

Comments

Spot|DSE wrote on 10/12/2004, 8:43 PM
Daisychaining is a GOOD idea, most of the time. USB 2 simply isn't reliable, as it's forced to share resources. On some systems, it does work, on others, it doesn't work. More common to find it not working than working.
MichaelS wrote on 10/12/2004, 9:39 PM
Thanks Spot. I'll chain'em together and give it a go.

While we're on the subject...is there a difference (speed/quality/reliability) between using the internal firewire port of a laptop and a PC Card (assuming drivers, etc. are all in order).

Frankly, the tiny 4 pin firewire plug has always made me a bit nervous. When recording direct from camera to disk, I'm always afraid that sucker is gonna fall out. My plugin firewire card provides for a six pin plug...a much more trustworthy connection.

Does anyone else share my "4 Pin Phobia"?
Liam_Vegas wrote on 10/12/2004, 10:02 PM
USB 2 simply isn't reliable

Might be true... I guess I may be one of the lucky ones. I have 3 USB2 / Firewire drives on my system... and I have them all plugged into the USB ports of my system. Never had a problem.
farss wrote on 10/13/2004, 1:19 AM
As drives you may not have a problem unless you have isochronous data going to them (jezz I hope I spelled that right) such as DV25. For most things the OS just copes with however slow the interface is. Probably in terms of getting a device to work, USB is much more reliable but you have to remember there's a huge difference between the data going to and fro from a keyboard than that going from a VCR to a HD.

To get back to the last question, yes those dinky little 4 pin connectors worry me as do those minature USB incarnations on my still camera. The only thing I don't like about the 6 pin firewire connections is the things have power on them and many times when I've missed the hole I've seen tiny sparks. I now power everything down before I swap things around.

Other problem we've found with the 4 pin cables is they fail all too easily. The expensive ones from Sony seem excellent but the cheaper ones fail where the cable enters the moulded plug.

Bob.
Edin1 wrote on 10/13/2004, 9:30 AM
Yup, you spelled it right! :-)
Anyways, I would say that both USB and Firewire are just as reliable, although Firewire should be a little more reliable, as well as faster, and that's because of the way they are wired.
Whether you are familiar with Electrical Engineering or not, this should be clear to you; USB has one data pair, while Firewire has two data pairs. While a USB device uses this one pair for both sending and receiving signals, Firewire has separate pairs, one for sending, and one for receiving.
This means that USB can't transmit data while receiving at the same time, and Firewire can. This also means that USB can't respond to commands as fast as Firewire, because it has to wait for data transmition to end.
And if you need to have a high-speed data transfer both ways at the same time, Firewire can do it at full-speed both ways (400Mbps both ways at the same time), while USB can, theoretically, do it at only half of its maximum speed (240Mbps both ways, one or more packets go one way, then one or more packets go another way).
Electrically, Firewire has the same physical connection as the twisted pair cable for Ethernet (Both USB and Firewire ARE, in fact, twisted pair cables, but USB has only one pair, and Firewire has two pairs, just like the Ethernet).

I hope some things are much clearer now.
R0cky wrote on 10/13/2004, 9:49 AM
As someone who has managed the design of USB interfaces (as in the chip implementation), I would go with firewire everytime.

The USB spec is hopelessly complex, impossible to implement so it works with everything (as everyone will make mistakes or misinterpretations), inconsistent, sucks, etc.

Firewire is much more stable.

rocky
riredale wrote on 10/13/2004, 5:39 PM
I also remember reading somewhere that the Firewire protocol is inherently better for streaming-type situations, but I can't remember exactly why. Something to do with one machine controlling the whole interchange, or something like that...
Steve Mann wrote on 10/13/2004, 11:27 PM
With Firewire, the peripherals talk to each other, start the data transfer then let it rip. USB requires the processor to be a traffic cop for every data packet.
DouglasClark wrote on 10/14/2004, 6:15 AM
From what I've read, the main difference for audio/video users is CPU utilization. As n19093's post suggests, USB/USB2 uses much more CPU than firewire. But that is only a concern if you're doing some other CPU-intensive processing at the same time, such as rendering or running alot of plugins. Then you might notice a difference in response.
xgenei wrote on 10/15/2004, 3:24 PM
use an adapater tail to upgrade the size and put a dab of Shoe-Goop glue on the small end? You can always pull it off if it gets in the way.

I use USB-2 for everything BUT capture.

Firewire daisy chaining will work well if you have decent electronics (not the expert here -- I can point you if you need.)

Another alternative that I haven't tried yet is serial drive via PCMCIA. Of course that would take a serial drive. That is a 1:1 port to drive (or 2:2).

I think cardbus would be more than fast enough to handle the data rate of two chained hard drives transferring data to each other, or one stream into or out of the laptop. I don't remember if cardbus is slower than PCI -- not significantly if at all.

I'll add a tip to get some gaffer's tape -- Markertek has a good stock. It will hold down just about any problem cable or connector and never leaves a residue and is dirt & weather resistent. I used it on a REAL tiny coax cable lead that "slips" into my wireless PC-card modem ($250!) Now I have to stop tripping over the cable otherwise instead of just yanking out the cable it could cause some serious damage (it's only 15' and it's next to impossible to extend). I wish I had a slip-on connector somewhere here -- other than at the modem of course.

BR -John