[ltp] External USB drive

[Matt Graham]

On Thursday 19 August 2004 13:23, after a long battle with technology, 
Hector Socas Navarro wrote:
> I recently purchased a 200Gb extrenal hard drive (USB 2). When I
> started using it I found it painfully slow
>   Timing buffered disk reads:  64 MB in 93.69 seconds =699.50 kB/sec
> Something's very wrong here. I should be getting ~40 MB/sec, right?

If your laptop has a USB2 port and you have the ehci-hcd module loaded, 
you should be getting ~15-20M/second.  40M/sec is the theoretical 
maximum speed of USB2, and you know that real-world usage always falls 
short of theory.

> Does anybody know why I'm getting this poor performance or how to fix 
> it? I'm running RedHat 7.3 with some updates and kernel 2.4.22 on a 
> T30.

Make sure that an EHCI chipset shows up when you do "lspci -v | grep -i 
ehci".  If there's no EHCI, you'll be stuck with USB1 speeds.  Then 
make sure that ehci-hcd is loaded; unless that module has been 
modprobed, you'll be stuck with USB1 speeds.  You might want to update 
that kernel as well, since USB2 support was introduced in 2.4.19 and 
some people have complained about it being unstable/broken in older 
kernels.  Latest is 2.4.26 or 2.6.7.

If an EHCI chipset is present and you have ehci-hcd loaded, but you're 
still stuck at USB1 speed, do "dmesg > file.txt", put file.txt on your 
webspace, then follow up to the mailing list with the URL.  HTH,

-- 
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