The term data block or block is used in different contexts. For example, in data transmission, in memory technology, in software and in connection with the term chunk.
- In data transmission, a data block, also called a data transmission block, is a transport unit with a case-by-case defined number of bits and characters. The data block describes the size and structure of a physical data unit to be transmitted, whereby the block elements and the block structure correspond to the conditions of the respective communication protocol. The data block is also referred to as a data transmission frame or frame. A data block is a self-contained, whole data set that is defined by its length. It has its own start and end boundaries and usually also control, path selection and error check character information. In bisynchronous procedures, this part of the message is terminated by an End of Block( EOB) or End of Transmission Block( ETB). If it is the last block of a message, the End of Transmission( EOT) or End of Text( ETX) is used.
- In storage technology, a data block is the smallest addressable storage unit of a block memory, cache, main memory, hard disk, floppy disk, compact disc( CD) or DVD. Each data block has its own address. For compact discs, a block or sector consists of a header, the actual data, error detection and correction, and control information. Each data block has its own identification with the Logical Block Number. The block size can be fixed or variable.
- In software, a block is a self-contained program section in a structured programming language.