Computer Functions, Input/Output, Binary

Computer Functions

• Computer functions include input, processing, output, storage, and communication.

Input Devices

• Purpose is to enter data and instructions into a computer.
• Examples include keyboards, mice, microphones, scanners, digital cameras, and styluses.

Output Devices

• Purpose is to send data out of a computer.
• Examples include monitors, printers, speakers, and earphones, which display text, pictures, sounds, and videos.

Binary System

• A system used to store, process, and exchange data in computers.
• During input, data is converted to binary; during output, binary is converted to human-readable format.
• Has two symbols: 0 and 1.
• A bit is a binary digit, the smallest unit of information and can have a value of 0 or 1.
• Computers use the system because it is easy to store using electricity, process with simple two-value operations, and read with only two options.
• Numbers, text, instructions, photos, and videos can be represented using the explained system.

Bytes and Data Representation

• 1 Byte equals 8 bits.
• Each bit represents a doubling of the previous value.
• A single bit can represent 2 options.
• Two bits can represent 4 options (0, 1, 2, or 3).
• N bits can represent 2^N options.
• A byte can represent 256 values.

Converting Between Binary and Decimal

• To convert from binary to decimal, one must convert 00100110. The binary bits line up with base values to give a weighted figure.
• 00100110 = 38 in decimal such that the corresponding powers of 2 are added (2 + 4 + 32 =38).
• 10101010 = 170 in decimal such that the corresponding powers of 2 are added (2+8+32+128 = 170)
• To convert from decimal to binary, one must convert 186 to binary.
• Binary is found to be 10111010 after a series of division steps by 2. Each stage flags odd/even number to translate to 1 or 0, working up the chain in reverse.

Even/Odd Numbers and Minimum/Maximum Values

• Even numbers in binary end with 0, while odd numbers end with 1.
• 1100 is equivalent to 12 in decimal and 1101 is equivalent to 13.
• Minimum is when all digits are zero, resulting in 0 in decimal; the maximum value is when all digits are 1 e.g. the 6 bit number “111111” is equal to 63

Text as Binary

• Codes represent each letter, digit, and special character
• ASCII has each character represented by a unique 8-bit code, 256 unique codes for letters, digits, and special characters.
• Unicode supports more than 100,000 unique characters via 16 or 32 bits and represents Chinese, Korean, Japanese, Arabic characters, and emojis.

Other Data Types

• Photos, videos, and audio can be represented through digitization, allowing storage in a computer.
• Devices used are called analogue-to-digital convertors (ADC).

Bits, Bytes, and Common Terms

• Byte (B) = 8 bits
• Kilobyte (KB) ≈ 1000 Bytes
• Megabyte (MB) ≈ 1000 KB or 1 million bytes
• Gigabyte (GB) ≈ 1000 MB or 1 billion bytes
• Terabyte (TB) ≈ 1000 GB or 1 trillion bytes
• Petabyte (PB) ≈ 1000 TB or 1 quadrillion bytes
• Data Transfer is measured in bits rather than bytes such as 100 Mb (100 Mega bits).