Types of External Memory

• Magnetic Disk

—   RAID

—   Removable

• Optical

—   CD-ROM

—   CD-Recordable (CD-R)

—   CD-R/W

—   DVD

• Magnetic Tape

Magnetic Disk

• Disk substrate coated with magnetizable material (iron

Memory Hierarchy

• Registers

—   In CPU

• Internal or Main memory

—   May include one or more levels of cache

—   “RAM”

• External memory