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.