Computer Main Memory And Its Types

Computer Memory

MEMORY IS THE INTERNAL STORAGE AREA OF THE COMPUTER. MEMORY IDENTIFIES THE DATA STORAGE.THE PHYSICAL MEMORY USUALLY REFERRED TO US MAIN MEMORY OR RAM.

TYPES OF MEMORY

• RAM

• ROM

RAM

RAM STANDS FOR RANDOM ACCESS MEMORY.IT WRITE DATA INTO RAM AND ASLO READ DATA FROM RAM. RAM IS A VOLATILE MEMORY.IT HOLDS DATA AS LONG AS THE COMPUTER IS SWITCHED ON.THERE ARE TWO TYPES OF RAM

• DRAM

• SRAM

• DRDRAM

DRAM

DRAM STANDS FOR DYNAMIC RANDOM ACCESS MEMORY. MOSTLY USED IN PERSONAL COMPUTERS.DRAM MUST HAVE ELECTRIC CURRENT TO MAINTAIN ELECTRICAL STATE(REFRESH).ITS ACCESS TIME IS 60 - 70 NAN0SEC0NDS.

SRAM

SRAM STANDS FOR STATIC RANDOM ACCESS MEMORY.ITS ACCESS TIME LESS THAN 60 NAN0SECONDS.

DRDRAM

DRDRAM STANDS FOR DIRECT RAMBUS DYNAMIC RANDOM ACCESS MEMORY.IT IS THE NEW TYPE OF RAM. IT ACCESS TIME 20 TIMES FASTER THAN DRAM.

ROM

ROM STANDS FOR READ ONLY MEMORY.IT IS A NON-VOLATILE MEMORY.IT READ DATA FROM MEMORY.

TYPES OF ROM

• PROM

• EPROM

PROM

PROM STANDS FOR PROGRAMMABLE READ ONLY MEMORY. IT ACTS LIKE A ROM. THERE ARE TWO TYPES OF PROMS.

• EPROM

• EEPROM

EPROM(ERASABLE)

EPROM STANDS FOR ERASABLE PROGRAMMABLE READ ONLY MEMORY. IT CAN BE ERASED AND REPROGRAMMED BY THE USER.

EEPROM(NON ERASABLE):

EEPROM STANDS FOR ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY.NONERASABLE PROMS CANNOT BE CHANGED ONCE THEY ARE PROGRAMMED.