show system snapshot media internal – To know Junos installed in both partitions of Ex

root> show system snapshot media internal 
fpc0:
--------------------------------------------------------------------------
Information for snapshot on       internal (/dev/da0s1a) (primary)
Creation date: Feb 11 23:59:41 2013
JUNOS version on snapshot:
  jbase  : ex-12.3R1.7
  jcrypto-ex: 12.3R1.7
  jdocs-ex: 12.3R1.7
  jroute-ex: 12.3R1.7
  jswitch-ex: 12.3R1.7
  jweb-ex: 12.3R1.7
Information for snapshot on       internal (/dev/da0s2a) (backup)
Creation date: Feb 6 08:38:13 2013
JUNOS version on snapshot:
  jbase  : 11.3R4.2
  jcrypto-ex: 11.3R4.2
  jdocs-ex: 11.3R4.2
  jroute-ex: 11.3R4.2
  jswitch-ex: 11.3R4.2
  jweb-ex: 11.3R4.2

{master:0}
root>

• show chassis firmware – Verify jloader version
• show chassis routing-engine
• Power supply not recognized by M-series router