What is a Bit?

Bit is considered the smallest unit of data or information that a digital computer can process. A bit can take one of two values, i.e. 0 or 1.

Bit forms the foundation upon which all digital data and information are developed, stored, and processed.

• Binary value − A bit can only hold one of two values: 0 or 1.
• Basic unit of data − It is considered the most basic unit of information that a computer can process.
• Combination with bytes − Multiple bits (usually eight) are grouped to form a byte, which is used to represent characters and other data types.

Represent Text in Bit

Using ASCII − Text can be represented in binary using ASCII (American Standard Code for Information Interchange), which shows binary numbers as bytes. A byte is made up of a collection of 8 bits. ASCII assigns a unique 7-digit binary code for each letter.

For example −

• C is 67 in decimal and 1000011 in binary (7 bits).
• O is 79 in decimal and 1001111 in binary (7 bits).
• D is 68 in decimal and 1000100 in binary (7 bits).
• E is 69 in decimal and 1000101 in binary (7 bits).

So, the word "CODE" in binary ASCII representation is: 1000011 1001111 1000100 1000101.

Using Unicode − Unicode assigns a unique code point to each character or symbol, representing it in hexadecimal form. To convert "HELLO" into binary using Unicode:

For Unicode representation of "code" −

• c = U+0063
• o = U+006F
• d = U+0064
• e = U+0065

In binary −

• c in binary = 0000 0110 0011
• o in binary = 0000 0110 1111
• d in binary = 0000 0110 0100
• e in binary = 0000 0110 0101

UTF-8 Encoding Rules

• For a code point between U+0000 and U+007F, use one byte and prefix it with a zero.
• For a code point between U+0080 and U+07FF, use two bytes and prefix them with 110 and 10.
• For a code point between U+0800 and U+FFFF, use three bytes and prefix them with 1110 and 10.
• For a code point between U+10000 and U+10FFFF, use four bytes and prefix them with 11110 and 10.

Since the code points of "hello" are between U+0000 and U+007F, one byte is used for each letter, prefixed with a zero.

• h = 0110 1000
• e = 0110 0101
• l = 0110 1100
• o = 0110 1111

When concatenated, the UTF-8 encoded word "hello" is: 01101000 01100101 01101100 01101100 01101111.

Represent Image in Bit

Images are represented by dividing them into small pixels and assigning binary codes to the different pixels based on their color and brightness. Larger image sizes mean more colors and shades are used. For example, in BMP format, a 3x3 pixel image using blue and green colors can be encoded as: 00000000 00000000 11111111 00000000 00000000 11111111 00000000 00000000 11111111

Each pixel uses 8 bits. The first row has three blue pixels (00000000 00000000), the second row has three green pixels (11111111 00000000), and the third row repeats the blue pixels.

Properties of Bit

• A bit is the smallest unit of digital data, containing only two values: 0 and 1.
• Each bit is independent and holds different data, meaning changing one bit does not affect the others.
• In Boolean algebra, values are either true (represented by 1) or false (represented by 0).
• When two bits are complementary (one is 0, and the other is 1), they form a dual relationship.
• The more bits used, the more data can be stored, thus increasing the accuracy of data (e.g., 8-bit, 16-bit, or 32-bit systems).

Uses of Bit

• Data Representation − Bits are the most basic unit for storing and representing data in various formats like text, images, video, and audio.
• Computer Processing − Since computers operate in binary, bits are used by CPUs (Central Processing Units) to manipulate data, execute software, and perform different tasks.
• Error Detection and Correction − In data communication, bits help detect and correct errors. Techniques like checksums and error-correcting codes ensure data integrity.
• Character Encoding − Bits are used in encoding techniques, such as ASCII and Unicode, to represent text, facilitating communication between humans and machines.
• Security − Encryption and security protocols rely on bits. Cryptographic algorithms, like XOR (exclusive OR), perform bitwise operations to handle data at the bit level.
• Compression − Compression reduces the size of data by removing unnecessary information from bits, often used in multimedia formats.
• Control Systems − Bits encode commands and states in digital control systems, enabling the automation of processes and systems.