show system storage partitions – Show active partitions information for the boot media in juniper ex

root> show system storage partitions 
fpc0:
--------------------------------------------------------------------------
Boot Media: internal (da0)
Active Partition: da0s1a         <<<< Ex is currently booted from slice da0s1a partition
Backup Partition: da0s2a
Currently booted from: active (da0s1a)

Partitions information:
  Partition  Size   Mountpoint
  s1a        183M   /         
  s2a        184M   altroot   
  s3d        369M   /var/tmp  
  s3e        123M   /var      
  s4d        62M    /config   

{master:0}
root>