Inert Detritus The Internet's dust bunnies

20 September 2007 @ 10am

USB 2.0, and FireWire’s Slow Demise

USB 2.0 versus FireWire 400 has been an interesting battle to follow. The original iPod was a FireWire-only device: USB 1.1 was too dog slow to even think about using it to fill a 5 GB hard drive. FireWire first appeared on a Mac in January of 1999, while USB 2.0 didn’t even appear on an Apple machine until 2003.

For hard drive transfers, FireWire is inarguably better: it had high sustained throughput, dedicated hardware chipsets, much more power coming over the (optional) two power pins, and memory-mapped transfers which allowed the host computer to stay out of the way during data transfers. USB 2.0, while technically specified with a higher possible bandwidth, was never able to support the time-sensitive, asynchronous data transfers that FireWire allowed. FireWire was king of the consumer realm for hard drives, burners, scanners, and DV cameras, especially on the Mac.

But USB 2.0 had one big thing going for it: it was backwards compatible with USB 1.1. Had a 2.0 device on a 1.1 computer? It worked, but it ran slow. 1.1 device plugged a 2.0 port? You didn’t even know the difference. USB 2.0, instead of being the new kid on the block, all ready had an “installed base” of millions of devices plugged into millions of machines. Sure, the speeds wouldn’t be 2.0, but they worked, and that was good enough for most users.

And so, with the inclusion of USB 2.0 on Macs starting in 2003, the near-ubiquity of them on the PC side, Apple voted in 2005 to drop FireWire support from the iPods, picking up a smaller form factor along the way (those separate hardware chipsets take up space, no matter how small you make them). FireWire slowly fell by the wayside.

I’m especially glad that from day one, I always bought dual-connection FireWire/USB 2.0 hard drive enclosures. Aside from making transfers from Mac to PC or back easy without having to have FireWire support on the PC side, it future-proofed things. If/when USB 2.0/3.0 took off, I knew I’d be able to plug the drives in and run with them, and not have to fret about the connection I was using.

Sadly, USB 3.0 will finish the job started by USB 2.0: the complete obsoletion of FireWire. As a higher speed, 2.0‑compatible connector (currently planned with a dual-use optical/wired cable, capable of 10x higher speeds than 2.0, and possibly, nay, probably 1.1‑compatible), it has all the makings of the next successful hardware protocol to connect devices to the computer.

(Wikipedia, as usual, has great articles for FireWire and USB.)