Computer capacity, for short, is a term used to describe the amount of data a computer can store and process. RAM (Random Access Memory) is a type of memory that stores data temporarily and is measured in 3 letters: bytes. MEGS (Megabytes) is a unit of measurement for digital information and is measured in 4 letters: bytes. ROM (Read-Only Memory) is a type of memory that stores data permanently and is also measured in 3 letters: bytes.