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Date: Tue, 17 Nov 2009 09:18:22 -0500
From: David Jackson <djackson452@gmail.com>
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Subject: Lockup problems with USB disks
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I have a USB hard drive.  Whenever I open two programs which utilise the 
USB hard drive simultaneously, these programs, i assume when they 
attempt to write to the hard drive lock up due to what i suspect must be 
some issue with the USB driver and perhaps a deadlock involving multiple 
concurrent accesses to the drive. When they attempt to access the drive 
the programs can lock up for several minutes before being unblocked. 
When only one program is using the drive this behaviour does not seem to 
occur.

It seems most likely that this is a USB level problem involving the USB 
drivers. I am using FreeBSD 7.1. It is annoying behaviour to say the 
least and I wonder what can be done about it, and if this issue is being 
addressed, perhaps in the recent redesign of the USB code. It seems to 
be a pretty consistent issue, happening with multiple installs of 
FreeBSD and different drives.

Thank you.