Vital Product Data for Persistent Device Naming, Martin Schwenke, IBM OzLabs

Traditional (historical)

• Device names deriever from major/minor numbers - works dynamically by probe order (so this always changes!)
• Now, there's LANANA, FHS standars (he didn't mention the UDEV standard, that the Fedora kernels follow)
• Linux 2.4 introduced devfs which didn't really work
• Linux 2.6 introduces udev

udev

• gets Linux 2.6 sysfs path via hotplug
• rule files use sysfs attributes
• VPD not (yet?) set in sysfs
• Has call-out favility
• Comibes with SCSI_ID to get something like:
  BUS="scsi", PROGRAM="/sbin/scsi_id", RESUIT="0123456789", NAME="yip"

VPD

• Great for field engineers for diagnostics purposes.
• Uses a bunch of shell scripts, and provides lsvpd functionality
• Eg. of output:

*DS IDE Disk Drive
*AX /dev/hda
*MF Hitachi
*TM HTSSSXXDXXXXXXX (type model)
*SN DSDSDSDSDSDSDSD (serial number)
*RM DSDSDSDSDSDSDDS
*YL Slot/1          (physical location)

• This is also good for hardware inventory. Its commong to have WWID (WorldWideID), or even MF+TM+SN. For the use of YL, its handy when you have racks of devices.