Hardware Reference
In-Depth Information
FireWire port in your PC and then use Windows Movie Maker (included with XP/Vista and a free
download from Microsoft for Windows 7/8) to capture or digitize the data from tape to the PC. Once
on the PC, it can be edited, copied, or uploaded to video sharing sites. Although many systems
include FireWire built in, if your system doesn't include a FireWire connection, you can easily add
one via an adapter card.
USB/FireWire Performance Myths and Realities
A student once wrote me to inquire about a question that appeared on a test in a computer class he and
his classmates had taken. The question was, “Which is faster, USB 2.0 or FireWire 400 (1394a)?”
They had answered that USB 2.0 was faster, because USB 2.0 was rated 480Mbps (60MBps),
whereas FireWire 400 was rated 400Mbps (50MBps). Well, after the test was graded the students
were shocked to find their answer had been marked wrong! Upon discussing the question in class, the
teacher confirmed the technical specifications but then went on to say that due to less internal
“overhead,” FireWire was faster than USB in the real world, even though the raw transfer speed
might be less on paper. The student was basically asking me what the correct answer to the question
really was.
I had to sigh. I
despise
questions like that because, from a technical standpoint, the question is so
poorly and imprecisely written that
both
answers are arguably correct. For example, it obviously
wasn't clear whether the question meant “faster” as in the raw bus speed or as in real-world
throughput. And if it did mean real-world throughput, under what circumstances exactly? Well, when
confronted with questions like that, where you
have
to make a choice one way or another, in general
the best thing you can do is to keep it simple and avoid overthinking the answer. Because real-world
testing involves many unknown variables, the simplest and most definitive answer would be based on
the raw transfer speeds alone. In that case, choosing the best answer would be simple: Because USB
2.0 transfers at 480Mbps (60MBps), and 1394a transfers at 400Mbps (50MBps), USB is faster.
Now I know some people reading this might disagree, including the teacher who gave the test
referenced by the student. Many people believe (and many tests have shown) that, whereas USB is
faster on paper, FireWire is faster in the real world. Although I hesitate to make blanket statements, I
would agree that just as with any interface or bus in a PC, there are many more factors contributing to
performance for a specific task under a specific set of conditions than just the raw bus speed
specification. Although many people assume that FireWire is faster in the real world, the truth is that
the designs of USB and FireWire are different, and one cannot necessarily predict the results of a
specific example without knowing all the relevant details.
To help make my point, I ran some tests and recorded the results. I had a 7200 rpm Maxtor 250MB
drive mounted in an external enclosure that supports
both
FireWire 400 (1394a) and USB 2.0
interfaces. The drive was formatted as a single FAT32 partition and was about half full. I created a
folder and copied a 300MB video file into the folder. I specifically selected a large file that would
not fit in any of the caches or buffers for either the drive or systems involved.
I used two systems to conduct the tests, and both included FireWire 400 and USB 2.0 interfaces. The
systems were as follows:
•
System 1
—Desktop, 3.6GHz Pentium 4 processor, 1GB RAM, Windows XP
•
System 2
—Laptop, 1.7GHz Pentium M processor, 1GB RAM, Windows XP
To test the throughput, I copied the file and measured the time in seconds for the command to
complete. This meant that the file would be read from and written back to the same drive, which
