sesd —
monitor SCSI Environmental Services Devices
  
    | sesd | [ -d] [-tpoll-interval] device
      [device ...] | 
sesd monitors SCSI Environmental Services (or SAF-TE)
  devices for changes in state and logs such changes changes to the system error
  logger (see syslogd(8)). At
  least one device must be specified. When no other options are supplied,
  sesd detaches and becomes a daemon, by default waking
  up every 30 seconds to poll each device for a change in state.
The following options may be used:
  - -d
- Instead of detaching and becoming a daemon, stay attached to the
      controlling terminal and log changes there as well as via the system
      logger.
- -tpoll-interval
- Change the interval of polling from the default 30 seconds to the number
      of seconds specified.
The user may then use
    getencstat(8) to get more
    detailed information about the state of the over enclosure device or objects
    within the enclosure device.
  - /dev/sesN
- SCSI Environmental Services Devices
This is something of a toy, but it is better than nothing.