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Denary or Decimal
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Base 10.
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Binary
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Base 2. Used by computers to represent all data and instructions. Uses 1s and 0s to powers of 2 to represent whole numbers.
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Hexadecimal
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Base 16. Used in computing because more values can be represented by fewer characters. This makes it easier for humans to read and understand.
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Denary to Binary
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Divide by 2, then read the remainders backwards.
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Binary to Denary
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Multiply the binary numbers (i.e. every single digit) by the relevant place value, then add all of these together.
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Denary to Hexadecimal
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Divide by 16, then read the divisors and remainder backwards. Then convert digits to hex digits.
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Hexadecimal to Denary
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1. Separate the hex digits
2. Convert each digit to binary 3. Concatenate, then convert to denary |
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Binary to Hexadecimal
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Convert to denary, then hex.
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Hexadecimal to Binary
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Convert to denary, then binary.
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Bit
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b
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A single binary digit.
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Byte
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B
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8 bits.
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Kilobyte
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kB
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1,000 bytes
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Megabyte
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MB
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1,000 kilobytes.
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Gigabyte
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GB
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1,000 Megabytes.
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Terabyte
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TB
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1,000 Gigabytes.
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What is ASCII?
A character set that uses 7 bits, so can represent up to 128 characters; this means that only Latin letters can be used (i.e. characters/letters from other languages can't be represented). However, it takes up less space that Unicode.
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What is Unicode?
Unicode is also a character set, but it can represent many, many values, including non-Latin-based languages.
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Pixel
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A single point in a graphical issues. Short for 'picture element'.
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Bitmap
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A grid of pixels, with each pixel represented by a binary number.
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Colour depth
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Number of colours that can (not necessarily are) be represented in an image, and the corresponding number of bits needed to represent each pixel (e.g. 2 bits for 4 colours). The greater the colour depth, the bigger the file size.
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Resolution depth
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How much detail there is in an image. The more pixels per inch, the higher the resolution. The higher the resolution, the bigger the file size.
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Metadata
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Gives the software the information needed to display the image properly (size, resolution depth, colour depth).
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Sample
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A measure of amplitude at a given point. Used to convert an analogue wave into a digital format.
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Sampling rate
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The number of samples taken in a second. Measured in Hertz.
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Sampling resolution
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The number of bits per sample.
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Bit rate
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The number of bits used per second of the audio. Usually measured in kilobits per second (kbps).
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
