One Pager Cheat Sheet

• We will learn about data sizes and their importance to effectively use computing resources in this lesson.
• It is important to become familiar with volatile and non-volatile memory, typically RAM and ROM respectively, as they have limited sizes ranging from 4MB to 8GB.
• Data is stored and measured in computers using binary bits with units ranging from bytes up to petabytes and beyond.
• All data, no matter its form, is stored as combinations of 0s and 1s (in machine code) on a computer.
• A byte is a unit of data storage made up of 8 bits, allowing it to store 256 binary values, representing a single character, number, letter, or symbol.
• The word "Monday" requires 6 bytes of memory due to each character being represented by 1 byte.
• While it is commonly thought that 1 Kilobyte = 1000 bytes, computers follow a binary system which means that 1 KiloByte = 1024 Bytes, which can be further represented as 8 bits x 1000 bytes = 8000 bits.
• The size of the text document in kilobytes is equal to 10,000 words multiplied by 5 letters per word and 1 byte per letter, divided by 1024, which equals 50 KB.
• A Megabyte (MB) is equal to 1 million bytes or 1024 kilobytes, and is expressed in bits as 8 x 10⁶, with HD images, audio and short video files typically stored in megabytes.
• A gigabyte (GB) is equivalent to 1024 megabytes (MB), or 8 x 10⁹ bits and is capable of storing a full 1 - 1.5 hour long HD movie.
• A terabyte (TB) is larger than a gigabyte and provides a storage capacity of up to 8 x 10¹² bits, allowing modern hard disk drives or laptops to have storage spaces of up to 1 to 2TB.
• Today, large databases require capacities of petabytes, like mobile phone networks which transmit up to 20 petabytes of data and Google's servers which process 24 petabytes of information every day.
• 1 GB is equivalent to 1,000,000 KB or 1,024 MB, so multiplying 1.5 GB by 1,000,000 (in decimal) or 1,024 (in binary) gives us 1,500,000 KB (in decimal) or 1,572,864 KB (in binary).
• Knowledge of data sizes is necessary to understand the memory structure and performance of a system, with various units ranging from bits to petabytes used to store different elements such as machine code, characters, documents, audio and video files, movies, and hard disk drives.