On Tue, 31 Jul 2007, Kostas Peletidis wrote: > Branden Sletteland wrote: > > I have also noticed this delay and have through instrumenting code > > have found that every block in the device gets read in. I never > > checked if it was something in the df, filesystem, SCSI, or USB > > subsystems that was causing this. I am usually doing df on USB > > storage devices formated as FAT 32 w/ and w/o LBA. > > > > Branden > > > > > Thanks for your reply Branden. This explains why df would delay for a > whole minute to terminate normally with a 500GB usb disk attached and > only for a second or two with a 512MB usb stick attached. Btw both are vfat. > > This brings another question though: Why read every single block during > the first run of df after the partition is mounted? Obviously buffering > 500GB for fast access is currently out of the question so could it be > the case that some sanity check was going on?
Nothing in the df, SCSI, or USB code would cause this. That seems to leave the filesystem or block layers as the most likely candidates. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
