On Tue, Apr 26, 2005 at 02:30:12PM +1000, Benjamin Herrenschmidt wrote: > Additionally, some machines won't properly park/flush the disk, it's > necessary to send the proper suspend commands to IDE hard disks prior to > shutting down or we risk data loss.
That sounds like the disk is caching write data. SCSI has a "Write Cache Enable" bit in the "caching mode page". See "scsiinfo -c" output. 10 years ago I measured/compared performance of disabling WCE (plus queue depth of 8) and enabling WCE (queue depth 1). It's a wash for the workloads I was testing. I was told "stupid OSs" that didn't know about tagged queueing needed WCE for benchmarks. HP cared for exactly the same reasons: Bus Resets or Disk power failure would cause data loss with WCE enabled. Disabling WCE on current OSs would solve the above problem IFF IDE/SATA also supports "cache mode" page. grant ------------------------------------------------------- SF.Net email is sponsored by: Tell us your software development plans! Take this survey and enter to win a one-year sub to SourceForge.net Plus IDC's 2005 look-ahead and a copy of this survey Click here to start! http://www.idcswdc.com/cgi-bin/survey?id=105hix _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
