External HD: is firewire 400 enough??

Question

I have Finalcut pro 5.0.4 running on my Powerbook G4 1,3GHz. It has firewire 400 + 800 + USB2 ports.
My camcorder is a Sony HDR-HC3 (firewire400).
I just finished my first project, which I had on a partition of my internal drive.
I did not encounter any problems.
Anyway, I want to buy an external drive, I do have the LaCie rugged (2,5", 5400rpm) in mind, as I travel a lot.
Obviously, I cannot do anything wrong, if I buy the triple interface (fw 400 +800 + USB2). But will firewire 400 or even USB2 be enough for my hardware-combination?
Thanks for your advise!

Answer 1

Luke,
Truth be told, Apple never sanctioned the use of external firewire drives for FCP but they can be made to work quite reliably over a very wide range of users. USB can't do that. Here's why.
If you read the specifications for usb 2.0, it appears fast enough - almost as fast as fw400. However, the real issue is the ability to send data through uninterupted. This become critical when you start pushing the number of simultaneous streams through - like trying realtime playback of 6 or more files.
There is a technical name for this capability - Isochronous - and USB is not set up that way. Without that dedicated bandwidth capability, video hicups, stutters, and FCP correctly reports dropped frames. SOME (like you) have made it work, but it really is a gamble and a poor one at that.
But, you cry in disbelief, Apple, the techno god, has pronounced usb 2.0 to be the future of the video iPod!
Well, who cares if the transfer of a mp3 or video to an ipod has minor hicups and does not happen in the streamingest manner - you are not VIEWING (or listening to ) the stuff as it flows accross. Minor interuptions are not an issue. However, when you need something to happen in real time with high data rates you want firewire or, increasingly, external SATA drives.
x
Isochronous
(from "how stuff works")
An important element of FireWire is the support of isochronous devices. In isochronous mode, data streams between the device and the host in real-time with guaranteed bandwidth and no error correction. Essentially, this means that a device like a digital camcorder can request that the host computer allocate enough bandwidth for the camcorder to send uncompressed video in real-time to the computer. When the computer-to-camera FireWire connection enters isochronous mode, the camera can send the video in a steady flow to the computer without anything disrupting the process.
(from Whatis)
In information technology, isochronous (from the Greek "equal" and "time"; pronounced "eye-SAH-krun-us") pertains to processes that require timing coordination to be successful, such as voice and digital video transmission. A sound or picture going from a peripheral computer device or across a network into a computer or television set needs to arrive at close to the same rate of data flow as the source. In feeding digital image data from a peripheral device (such as a video camera) to a display mechanism within a computer, isochronous data transfer ensures that data flows continously and at a steady rate in close timing with the ability of the display mechanism to receive and display the image data. (FireWire, the IEEE 1394 High Performance Serial Bus, includes an isochronous interface.)
Isochronous can be distinguished from asynchronous, which pertains to processes that proceed independently of each other until a dependent process has to "interrupt" the other process, and synchronous, which pertains to processes in which one process has to wait on the completion of an event in another process before continuing.
Technical Explanation:
http://www.techfest.com/networking/wan/isoc.htm