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Re: [Phys-l] digital video cameras



Stefan!

As I wrote Apple goofed. My PB G4, at the time of purchase, was the top of the line for a 15". Supposed ports: both firewires and two USB 2's. Their specs. claim the "power" from the USB ports is one A. @ 5V. Therefore, I was surprised when the WD (W'ern Digital) ext. HD wouldn't run, yet runs on my old 867 MHz 15"er. So I cut a cable (white & green, black and red) loaded it w/ an old CENCO tubular pot. while monitoring the current and EMF. The internal R for the old PB pc is 0.43 Ohms; the new 0.69. Then I checked time, for the same file, transfer. the Fact that the FW was ~ 2X the USB should've clued me that the USB was a 1 instead of a 2. Anyway after a week at the shop (Apple authorized) I called to pick it up. Sorry it's in Texas; the ports are 1's not 2's that's why it won't run your WD HD. Balderdash on the won't run -- I told them it ran on the ones in my old PB. I didn't tell them about my frosh Physics exercise.

Wikipedia to the rescue:
(More than you want to know.)

http://en.wikipedia.org/wiki/USB#USB_2.0_Hi-Speed_vs_FireWire


[There are, evidently, numerous versions of USB.]

bc, who prays the USB is the only goof -- I hadn't checked if it'll record double layer.

p.s. I don't own a hub and used only one FW cable.


Stefan Jeglinski wrote:

"Firewire is the way to go. Tens to hundreds
of times better bandwidth than usb."

Not quite not even 2 X.


Depends on which Firewire (400 or 800) you are comparing to which USB (1.1 or 2).



I have an ext. HD and a PowerBook both w/ usb and FW. I found the difference sl. less than 2X transferring the same ~ 100 Meg file and that was w/ USB 1.0!


Something is wrong if this is true. Theoretically, FW400 is 36x faster than USB 1.1, although you may not see this in practice. But it should do better than 2x.


Apple goofed; my PB is supposed to have 2.


I am unaware of any PBs that do not have the rated USB ports that are claimed. Keep in mind that a USB 1.1 device on a 2.0 hub will make all items connected to that hub run at 1.1 speeds.



Here's a believable? Site on this matter.

http://www.usb-ware.com/firewire-vs-usb.htm


Yes, a fair comparison.


Stefan Jeglinski
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