The term memory refers to a chip that stores data. The data is retrived from the memory by the microprocessor for processsing when required. When we store data and information in the computer it is saved in the memory. Memory can be divided into two types, volatile memory and non- volatile memory. Volatile memory stores data temporarily and it loses the data as soon as the power supply is turned off (ex-RAM). Non-volatile memory stores data permanently and it does not lose the data even when the power is turned off. Further we can divide physical memory into two types, they are primary and secondary. Primary memory are of two types : <br><b>RAM</b> (Random Access Memory) <br><b>ROM</b> (Read Only Memory) The different types of ROM are: <br><b>PROM</b> (Programmable Read-Only Memory) <br><b>EPROM</b> (Erasable Programmable Read Only Memory) <br><b>EEPROM</b> or <b>Flash ROM</b> (Electrically Erasable Programmable Read Only Memory) Secondary Memory are Hard Disk Drives, Floppy Drives, DAT, ZIP Drives etc.