Definition of memory and its classification

Memory Hierarchies

Definition of memory and its

classification

Ø Memory

• When you launch a program, it is loaded into and run from memory

Ø Classification of Memory

Ø Internal Processor Memory

Ø Main Memory:

Example: RAM, ROM.

Ø Secondary Memory:

Example: CD, Floppy etc.

Memory Capacity

ü Bit

ü Byte: 1 byte= 8 bits

ü Kilobyte (K or KB): 1KB=1024 bytes

ü Megabyte (M or MB): 1MB=1048579 bytes

ü Gigabyte (G or GB): 1GB=1048876 byte

ü Terabyte

Memory Hierarchies

General Properties of Memory Devices

• Access Time: The average time required to read a fixed amount of information from the memory

• Cycle time: The minimum time between two consecutive memory access operations is called the cycle time.

• Data Transfer rate: The maximum amount of information that can be transferred to or from the memory every second is called the data transfer rate.