Controlled shutdown concepts

Before you use a power-handling program to control system shutdown, you may want to familiarize yourself with related concepts.

• Battery backup unit
  A Battery Backup Unit (BBU) provides a safety net for users who do not have an uninterruptible power supply or those with a failed uninterruptible power supply.
• Handling uninterruptible power supply conditions when no power-handling program exists
  Use this topic to learn about considerations when you are not a power-handling program to handle controlled system shutdown.
• IPL considerations for uninterruptible power supply
  When the system performs an IPL, the Licensed Internal Code verifies various internal switches to see if the system was correctly powered down.
• Power loss controlled shutdown
  The power loss-controlled shutdown mechanism allows the system to shut down in an orderly fashion following a loss of utility power. The power loss-controlled shutdown mechanism is available only if you connected the system to an uninterruptible power supply.
• Power restore IPL system value (QPWRRSTIPL)
  This value controls what happens if the system ends when utility power is interrupted and then restored at a later time.
• Uninterruptible power supply
  An uninterruptible power supply provides a source of ac power if utility power should fail. Typically, uninterruptible power supplies have a finite backup time.
• Uninterruptible power supply delay time system value (QUPSDLYTIM)
  QUPSDLYTIM is the system value for the Uninterruptible power supply delay timer.
• Uninterruptible Power Supply Message queue system value (QUPSMSGQ)
  The Uninterruptible Power Supply Message Queue (QUPSMSGQ) system value determines which message queues the power supply messages are sent to.
• Uninterruptible power supply messages
  Use this topic to learn about error messages related to uninterruptible power supply.
• Weak battery condition signal from uninterruptible power supply
  When the battery on the system falls below a specific level of charge, the uninterruptible power supply will issue a weak battery condition signal.