CCEA GCSE Digital Technology

## Data and information **Data** is a raw collection of facts, figures or symbols that has no meaning by itself. The number 67, the word "Belfast" and the date 18/05/2023 are all data. **Information** is data that has been processed, organised or put in a context so that it means something to a person. A list of test marks is data; a statement that the class average was 67, with the marks sorted and labelled by subject, is information, because someone can now act on it. The same item can be either depending on context. A value of 57 on its own tells the reader nothing, but 57 in a column headed "Communications mark" is information. Computers store and process data, and the software that presents the results is what turns it into information. ## Units of storage A computer stores everything as binary digits. A **bit** (binary digit) is the smallest unit of data and holds either 0 or 1. Bits are grouped so that larger amounts can be described. | Unit | Size | |---|---| | bit | a single 0 or 1 | | nibble | 4 bits | | byte | 8 bits | | kilobyte (KB) | 1,024 bytes | | megabyte (MB) | 1,024 kilobytes | | gigabyte (GB) | 1,024 megabytes | | terabyte (TB) | 1,024 gigabytes | A byte is the amount normally used to store one character of text, which is why file sizes are given in bytes and their multiples. The factor of 1,024 is $2^{10}$ and follows from computers counting in binary; some manufacturers of storage devices round it to 1,000 when they advertise capacity, which is why a…