2.2 Number system and representation

The binary (base 2) number system is used to represent the electronic status of the bits in memory. It also used for other purposes such as addressing the memory locations. Another number system commonly used with the computers is hexadecimal numbers (base 16). The computer uses the hexadecimal number system to communicate with the programmer when the problem with a program exists.

Decimal Number System
Familiar use in everyday life
Consists of numbers 0-9
Decimal digits are joined together to form longer decimal numbers
Example: 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12,……

A base 10 number system.
The base of the number system indicates how many symbols it uses.
It uses 10 symbols (0 – 9).
Each symbol has a value associated with it.
Example:
310 (3) represent the quantity of three.
 510 (5) represent the quantity of five.

2.1.3 Computer storage

Storage
- Holds data, instructions, and information for future use.

Storage medium
- Physical material on which a computer keeps data, instruction and information.

Storage Capacity
- Number of bytes (characters) a storage medium can hold.



Typical storage and capacities





Conversion
Example 1




Example 2

Convert 1.2 GB to KB.
Solution:
1.2 GB
= 1.2 x 210  x 210  KB
= 1.2 x 220   KB.
 
Example 3
Convert 1200 MB to GB.
Solution:
1200 MB
= 1200 / 210 GB
= 1.17   GB.