Although computers/computing systems are complicated, i.e the microelectronic technology they are developed from, or the application they are used in, in essence what exists is a decision-making unit. Decisions can be referred to as set tasks written in software, which are true or false. These true or false-valued signals can be expressed as digital. Digital refers to two states e.g light switch, buzzer, car alarm etc. A analog system is one that varies continuously in time e.g car temperature gauge, thermometer etc.
Decimal Numbers
The number system that is commonly used is that of base 10, ie using 10 digits 0 to 9. Consider the following number 41810.
The small ten represents the base of the number and is important when performing operations in computing arithmetic, else in this case 418 could mean anything.
The number 219 represents in base 10, 2 hundred, 1 ten, and 9 units, hence 21910. Hence it can be seen from this that, the furthest right digit, or least significant digit (LSB) is the unit 1 (100 ), the next one is 10’s (101 ) and the next 100’s ( 102) and so on.
So
219 = ( 2 x 100) + (1 x 10) + (9 x 1)
21910 = (2 x 102 ) + (1 x 101 ) + (9 x 100 )
Binary Number Systems
With Binary number system you have 2 digits only, which can be 1 or 0 only e.g 10102. These digits are sometimes referred to as bits. Hence the smallest unit of data is a 1 or 0. A collection of bits, is called a byte, 8 bits long. A nibble is half a byte or 4 bits. A word is a complete unit of information and consists of one or more bytes. Large collection of bits and bytes can be collectively known as kilobytes KB, (approximately 1000, actually 1024) or kilo bits Kb.
