On Tue, Jun 10, 2008 at 2:07 PM, John Huttley <John@xxxxxxxxxxxxxxxxxx> wrote: > Hi folks, I've been pokeing in scsi_id trying to understand the serialnumber > part. > > I don't understand the choices patrick made in doing this. > My note to patrick follows: > > > Hi patrick, > > I'm trying to undertstand your scsi_id program. > > I'm testing on an LTO drive and the code > seems to call > > do_scsi_page83_inquiry() which returns the (not really) serial number. > > Why are you doing that? The page is. > > sg_inq -vpd --page=0x83 /dev/st2 > VPD INQUIRY: Device Identification page > inquiry cdb: 12 01 83 00 fc 00 > inquiry: requested 252 bytes but got 42 bytes > Designation descriptor number 1, descriptor length: 38 > id_type: T10 vendor identification, code_set: ASCII > associated with the addressed logical unit > vendor id: HP > vendor specific: C7438A HU107108XD > > > > Why not get the real serial number from page 0x80?? > > sg_inq -vpd --page=0x80 /dev/st2 > VPD INQUIRY: Unit serial number page > inquiry cdb: 12 01 80 00 fc 00 > inquiry: requested 252 bytes but got 14 bytes > Unit serial number: HU107108XD > close error: No medium found Did you read the scsi_id man page? >From the description part: -- Start -- Description scsi_id queries a SCSI device via the SCSI INQUIRY vital product data (VPD) page 0x80 or 0x83 and uses the resulting data to generate a value that is unique across all SCSI devices that properly support page 0x80 or page 0x83. If a result is generated it is sent to standard output, and the program exits with a zero value. If no identifier is output, the program exits with a non-zero value. scsi_id is primarily for use by other utilities such as udev that require a unique SCSI identifier. By default all devices are assume black listed, the -g option must be specified on the command line or in the config file for any useful behaviour. SCSI commands are sent directly to the device via the SG_IO ioctl interface. In order to generate unique values for either page 0x80 or page 0x83, the serial numbers or world wide names are prefixed as follows. Identifiers based on page 0x80 are prefixed by the character 'S', the SCSI vendor, the SCSI product (model) and then the the serial number returned by page 0x80. For example: # scsi_id -p 0x80 -s /block/sdg SIBM 3542 1T05078453 Identifiers based on page 0x83 are prefixed by the identifier type followed by the page 0x83 identifier. For example, a device with a NAA (Name Address Authority) type of 3 (also in this case the page 0x83 identifier starts with the NAA value of 6): # /sbin/scsi_id -p 0x83 -s /block/sdg 3600a0b80000b174b000000d63efc5c8c -- End -- -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
