[Gllug] USB Discs

[Stephen Harker]

Mike Brodbelt wrote:
> On Tue, 2002-11-05 at 18:05, Andy Farnsworth wrote:
> 
>>Whoops, I don't know where you got your numbers, but lets work them through.
>>
>>USB - 12 Mb/s =~ 1.5 MB/s
>>USB 2.0 - 480 Mb/s =~ 60 MB/s
>>Firewire - 400 Mb/s =~ 50 MB/s
>>
>>While these throughput speeds are maximums, hard drive sustained transfer
>>speeds are much less.  As long as you are reading from the Hard Drive's
>>cache you will reach these speeds.  A decent IDE drive will get 35 MB/s
>>(about 20x faster than USB 1.1) while a laptop drive will get less than
>>that.
> 
> 
> FWIW, I've been using an Iomega Peerless drive with a Firewire
> interface. On a 20Gb Iomega catridge, formatted with XFS, sustained
> write speeds of approx 17MB/s seem reliably reachable. I've found the
> kernel firewire support in 2.4.19 to be fine.

Well it seems to be working great
I got a LaCie 120GB 7200RPM USB2 drive and it worked perfectly under 
Mandrake 9.0 (linux 2.4.19).
In fact, it detected the drive and set up an fstab entry and put an ICON 
in the KDE desktop!!
USB 2 is supported fine and I can transfer to and from at about 10 - 12 
MB/s although I have only just connected it up so it may vary with 
larger files w/out caching etc...
The kernel uses scsi emulation to map the USB device as a scsi drive so 
it appears as /dev/sda (on my machine with no other SCSI hard discs)
Nifty :-)
Steve


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