Definition of Memory
A memory is a device that is used for storing data or information either permanently or temporarily.
Example of Some Memory Devices: RAM, ROM, Hard Disk, CD, DVD, Cache Memory, Pen drive etc.
Functions of Memory
The primary functions of Memory is listed below:
- Memory stores data and instructions received from the input device for processing.
- It supplies information to the ALU when required.
- It receives partial or final results from the ALU.
- It supplies final results to the output device.
Memory is needed for the following purposes:
- i) To store the program and data during execution.
- ii) To store the program for repetitive use.
- iii) To store the data for future or periodical use.
- iv) To store the result of execution.
Capacity of a Memory
Capacity of a memory is defined in terms of the number of bits that can be stored in that memory device.
- Memory capacity is expressed in a number of units. Some of them are expressed below:
BIT:
- It is the abbreviation of Binary Digit, which is either a 0 or a 1.
- It is the smallest unit of information that can be stored by a digital computer. That is, either a 0 (zero) or a 1 (one) is called a bit.
Byte:
- A combination of 8 bits is called a byte, i.e. 1 byte= 8 bits.
Nibble:
- A collection of 4 bits is called a nibble, i.e. 1 nibble= 4 bits= ½ byte
1 Byte = 8 Bit
1 KB (Kilobyte) = 1024 Byte
1 MB (Megabyte) = 1024 KB
1 GB (Gigabyte) = 1024 MB
1 TB (Terabyte) = 1024 GB
1 PB (Petabyte) = 1024 TB
1 EB (Exabyte) = 1024 PB