What is the difference between immediate access storage and backing storage?

Immediate access storage, often referred to as primary storage, includes volatile memory like RAM that provides fast access to data for active processes. In contrast, backing storage, or secondary storage, includes non-volatile devices like hard drives and SSDs that store data long-term but offer slower access speeds. While immediate access storage is crucial for processing tasks in real-time, backing storage is essential for retaining data even when the system is powered off.