Computer Data Representation

Computer Readable Data

• Bits are the fundamental units of data in computers, and all data is represented as binary digits (0s and 1s).
• Converting human data, such as pictures, text, voice messages, and colors, into computer-readable data has taken years of development by individuals and companies.
• Any color can be converted into binary digits based on its composition of red, green, and blue values.

Storing Data

• Computers don't store symbols or characters, but rather combinations of 0s and 1s that represent them.
• The letter "a" is represented as 01100001 in binary, which is stored as a combination of on and off transistors in the computer.
• Simplicity is key at the hardware level, so using binary representation is more practical and efficient.

Data Representation

• Binary representation of data is an ancient concept, similar to Morse Code, which uses combinations of short and long beeps to represent language.
• Smoke signals were used to communicate between villages, using short puffs (0s) and long puffs (1s) in different combinations to send different messages.
• New ways of representing data using binary interpretation are constantly being invented, allowing for more technological advances.

Binary Data Representation

• A "bit" is a single binary digit holding either a value of 0 or 1, with only two possible options (yes or no, true or false).
• The number of possible combinations of binary digits doubles with each additional bit:
  • 1 bit has 2 combinations
  • 2 bits has 4 combinations
  • 3 bits has 8 combinations
  • 4 bits has 16 combinations
  • n bits has 2^n combinations
• Binary has a base-2 number system, with only two possible numerals: 0 and 1.

Storing Text and Characters

• A single byte (8 bits) can store exactly one character, with 256 possible combinations.
• A table can be created to represent characters using binary numbers, but this approach has limitations and requires global agreement.

Computer Memory

• Computer memory is stored in bytes, with larger units including kilobytes (kB), megabytes (MB), and gigabytes (GB).
• A kilobyte is equal to 1024 bytes, a megabyte is equal to 1024 kilobytes, and a gigabyte is equal to 1024 megabytes.
• Larger units, such as terabytes (TB) and petabytes (PB), are less commonly used but may become more important in the future.

ASCII Chart

• The American Standard Code for Information Interchange (ASCII) is a character set that assigns binary values to characters.
• ASCII has no specific reason for its assignment of characters, but it has been globally agreed upon and recognized.
• The ASCII Table is too large to display on one slide, but it encodes numbers, letters, symbols, and punctuation, as well as non-printable commands.
• The chart is based on English letters, but other languages translate their letters to English equivalents that align with the chart.

Learn how computers store and represent data, including binary digits, conversion of human data into computer-readable format, and color representation.