Date: Mon, 26 Oct 2009 05:48:16 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: hselasky@c2i.net Cc: hackers@FreeBSD.org, non@ever.sanda.gr.jp, freebsd-usb@FreeBSD.org Subject: Re: Help troubleshooting... Message-ID: <20091026.054816.1631944692.imp@bsdimp.com> In-Reply-To: <200910260959.20772.hselasky@c2i.net> References: <20091025.133437.-1844000782.imp@bsdimp.com> <4AE4E7AF.8060103@ever.sanda.gr.jp> <200910260959.20772.hselasky@c2i.net>
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In message: <200910260959.20772.hselasky@c2i.net>
Hans Petter Selasky <hselasky@c2i.net> writes:
: On Monday 26 October 2009 01:05:03 non@ever.sanda.gr.jp wrote:
: > M. Warner Losh wrote:
: > > I have a usb stick (8GB) on it. This stick has about 5GB of junk on
: > > it at this point.
: > >
: > > I tried to do 'cat * > /dev/null' recently, to measure how fast it
: > > goes. It got about 1GB into the drive and then I got device missing
: > > messages.
: > >
: > > So devfs thinks the device went missing:
: >
: > Warner-san, maybe it is caused by the hardware problem on the USB flash
: > memory. Some chip on the memory might have too much heat when you access
: > the memory at fast rate. Then it stops working.
: >
:
: What happens if you read from two USB disks at the same time?
I know that the august 25th version failed badly when I tried to burn
DVDs from a USB drive to a USB attached DVD burner. This used to work
flawlessly.
: If the device went missing the USB HUB signalled that. This is maybe an
: indication that the USB firmware on the device crashed. Maybe this is due to
: heat, or unhandled race conditions when the load goes high.
This same flash drive will do 20MB sustained on windows without a
glitch using similar commands.
: Try using "dd" and vary the block size from 512 to 65536 bytes. Does it stop
: working with all block sizes over time?
Once I get the message I posted, it is lights out for da0. No further
access to the drive works at all.
Warner
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