Byte was coined by Werner Buchholz in 1956 for IBM Stretch computer. Term originally meant any number of parallel bits from 1 to 6. Early computers used 4-bit BCD and 6-bit FIELDATA codes
Digital data represents information as discrete symbols with finite values. Binary data uses 0s and 1s, most common in modern systems. Digital data differs from analog, which uses continuous real numbers
Binary code uses "0" and "1" to represent data using binary digits. A byte of 8 bits can represent 256 possible values. Binary codes can be fixed-width or variable-width
Powers of two are numbers of form 2n where n is an integer. Non-negative powers of 2 are integers, like 20 = 1 and 21 = 2. Negative powers of 2 are fractions, like 1/2, 1/4, 1/8, 1/16
A numeral system is a mathematical notation for expressing numbers using symbols. Different systems can represent the same number using different symbols. The number represented by a numeral is called its value
Kilobyte (kB) is defined as 1000 bytes in SI system. One kilobyte equals 8000 bits according to IEC 80000-13. SI prefixes should only be used for powers of 10