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Once you turn off read cache, than you should be able to use READ VERIFY as well. The advantage to READ VERYIFY is no data transfer occurs between HOST and DEVICE thus speeding up the whole process tremendously. gkl -----Original Message----- From: Hale Landis [mailto:[EMAIL PROTECTED]] Sent: Tuesday, September 10, 2002 4:18 PM To: T13 List Server Cc: Ray Clutts Subject: Re: [t13] Read Verify Sectors This message is from the T13 list server. That someone is correct. The ATA definition of READ VERIFY (and READ VERIFY EXT) does not require the device to actually read the media - the ATA/ATAPI standard only says "the device shall have read the data from the media" - it does not say the data shall be read during the command execution. That means that data in the device's cache can be assumed to also be OK on the media. If you want to read the media, then I suggest you turn off the devices read/write cache (see the SET FEATURES command) and then use one of the read commands. --Original Message Text--- From: Ray Clutts Date: Tue, 10 Sep 2002 17:55:43 -0500 Read Verify Sectors Does anyone know of any reason that a Read Verify Sectors command could not be used to verify that the disk surface is basically error free? I am attempting to write a diagnostics package for testing hard drives and I would prefer to use the quickest command possible to verify that the surface is basically error free in the quickest possible time. Somewhere along the line, someone thought that the implementation of this command was vendor specific and that there were some vendors who basically treated this command as a NOP type of command and that the verification was not made. Ray Clutts Service Electronics [EMAIL PROTECTED] *** Hale Landis *** www.ata-atapi.com ***
