Question about USB R/W Speed

Mark Phillips mark at phillipsmarketing.biz
Thu Feb 2 09:07:23 MST 2012


On Thu, Feb 2, 2012 at 9:02 AM, Matt Graham <danceswithcrows at usa.net> wrote:

> From: Mark Phillips <mark at phillipsmarketing.biz>
> > Gnome reported that the transfer speed was around 400 - 500 KB/sec.
> > I then plugged the same stick into the same port on my laptop, but
> > transferred files (~1.5 GB lots of little files) from Windows 7
> > running in VMPlayer, and got a transfer speed of 4-5 MB/sec - 10
> > times faster! Is there some magic in windows that makes USB sticks
> > faster?
>
> If ehci_hcd isn't loaded, then USB2 devices will be limited to USB1 speeds.
> If a device is mounted with "-o sync", I/O on that device will be slower
> (but
> it shouldn't have been that slow).  If you're using an automounter, that
> automounter may mount removable media with -o sync .  Finally, your USB
> device
> may have some sort of flag in unusual_devs.h that says "This device may not
> work reliably at high speed; force it to low"--but I think that'd be
> unlikely.
>  Check the presence of ehci_hcd first.
>
> OK, # lspci |grep -i ehci
00:1a.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI
Controller #2 (rev 03)
00:1d.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI
Controller #1 (rev 03)

I assume that means it is ok. How do I check if devices are automounted
with -o sync (debian testing)?

Mark
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