Memory is the part of a computer that stores data, programs and instructions that are currently in use. Primary memory is located inside the computer. The WITCH has ⅓ Kb primary memory (RAM), made up of 828 Dekatrons in nine separate units. A type of valve, a dekatron is is a small counting tube that contains neon or helium to create a glowing charge. Each dekatron is capable of storing a single decimal digit. The WITCH is one of the only computers in the world that has a memory that can be read visually, thanks to its bulk use of Dekatrons.