The boot media stores a primary and secondary set of ONTAP image files that the system uses when it boots.

A controller consists of a board, firmware, and software. It controls the drives and runs the ONTAP operating system software.

A dual in-line memory module (DIMM) is a type of computer memory. They are installed to add system memory to a controller motherboard.

A fan cools the controller.

The NVRAM (Non-Volatile Random Access Memory) is a module that allows the controller to protect and save in-flight data if the system loses power. The system ID resides in the NVRAM module. When replaced, the controller assumes the new system ID from the replacement NVRAM module.

The NVRAM battery is responsible for providing power to the NVRAM module while data in-flight is being destaged to flash memory after a power loss.

The I/O module (Input/Output module) is a hardware component that acts as an intermediary between the controller and various devices or systems that need to exchange data with the controller.

A power supply provides a redundant power source in a controller.

A real time clock battery preserves system date and time information if the power is off.

The System Management module provides the interface between the controller and a console or laptop for controller or system maintenance purposes. The System management module contains the boot media and stores the system serial number (SSN).