Introduction to computing
Number System:
It is a writing system for expressing numbers, that is a mathematical notation for representing numbers.
Different numbers are used to represent different quantities. We need simple numbers to represent
huge quantities that is why different number systems have created in order to get simpler and simpler
symbols. There are many kinds of numbers such as integers, whole numbers, natural numbers,
imaginary and rational numbers etc.
Binary number system:
Any physical system that can exist in two distinct states (0-1, on-off, high-low, yes-no, up-down). A
binary digit is called a bit, usually expressed as 0 and 1. A series of 8 bits is called a byte. We can convert
decimals to binary by repeatedly dividing by 2, the base of the binary system. Collecting the remainders
from our repeated divisions will give us binary answer.
Among all the number systems decimal is the simplest one (0,1,2,3,4,5,6,7,8,9) and with the help of only
10 digits we can represent huge numbers. Most of the number systems are very complex compare to
decimal system.
Data representation:
1. Bits: The smallest unit of data on a binary computer. Since a single bit is capable of representing
only two different values. Within a single bit we can represent any two distinct items 0-1, truefalse, on- off and so on. A single bit is also used to represent numbers like 1023, 2465. We can
also use single bit to represent green and white color. Two un-related objects can also be
represented by a single bit for example 1234-red color.
2. Nibbles: It is a collection of 4 bits. This data is used in two items (BCD) and hexadecimal digit.
With a nibble we can represent up 16 distinct values. In case of hexadecimal numbers
(0,1,2,…,9,A,B…,F) are represented with 4 bits. BCD uses ten digits (0,1,2,3….,9).
3. Byte: Consists of 8 bits and is the smallest addressable data item. The bits in a byte are normally
numbered from 0 to 7. A byte represents 256 different values. The most important use of a byte
is holding code characters typed on the keyboard, displayed on the screen, and print on the
printer with numeric values.
4. Words: A word is a group of 16 bits. They are numbered from 0 up to 15 with 16 bits. We can
represent 65536 different values. The three major uses for words are integer values, offsets, and
segment values.
COMPUTER SCIENCE: Is the study of the theoretical foundations of information and computation
and practical techniques for their implementation and application in computer systems. We use
numbers for mathematical caculations. Computer executes data in the form of binary numbers.