Definition: storage hierarchy

The range of memory and storage devices within the computer system. The following list starts with the slowest devices and ends with the fastest. See storage and memory.

 VERY SLOW
 Punch cards (obsolete)
 Punched paper tape (obsolete)

 FASTER
 Bubble memory (obsolete)
 Floppy disks (obsolete)

 MUCH FASTER
 Magnetic tape
 Optical discs (CD, DVD, MO, etc.)
 Magnetic disks
 Low-speed bulk memory

 FASTEST
 Flash memory
 Main memory (DRAM)
 Cache memory (SRAM)
 Microcode
 Registers