usb 2.0

[Laurent GUERBY]

On Wed, 2003-12-17 at 05:29, clemens at dwf.com wrote:
> > I have a question about whether or not fedora is able to utilize usb 2.0
> > yet?  If so, what cards might be compatible with fedora?  What kind of
> > speeds can be expected?  
> 
> I had problems with my (off brand?) USB2.0 card / USB Disk up to the curreng
> jumbo patch for 2.6.0-test11.  With it, it works like a champ.  I see 16MB/s
> transfer rates, which is probably limited by the disk hardware.

I see 11 to 15MB/s with my external USB2 drive, the
the exact same disk is doing around 50MB/s when I plug
it on IDE within my computer (same kernel 2.4/fs/test procedure).

I assume either the culprit is one of
- USB2/IDE chip on the external drive
- USB2 chip on my board (ASUS A7N8X deluxe, nforce2 USB controller)
- USB2 standard for usb-storage is limiting effective use of bandwidth
- linux kernel driver

I didn't try to dig or ask experts about it. I've seen
benchmarks for such external disks on the web, and the result
were closer to the theoretical max than what
I'm observing, so it's likely to be a linux kernel issue.

Laurent