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
   Floppy disks

      MUCH FASTER

   Magnetic tape
   Optical discs (CD-ROM, DVD-ROM, MO, etc.)
   Magnetic disks with movable heads
   Magnetic disks with fixed heads (obsolete)
   Low-speed bulk memory

      FASTEST

   Flash memory
   Main memory
   Cache memory
   Microcode
   Registers