A buffer is an area of memory set aside for temporary storage of data while it is being moved from one place to another. This is typically done to speed up processes with significant latency, such as writing to a disk, printer or other physical device. The output is ready to be sent to the device before the device is ready to accept it, so it is moved to the buffer so that the sending program does not have to continue waiting.
A buffer may be used when moving data between processes within a computer. This is comparable to buffers in telecommunication. Buffers can be implemented in a fixed memory location in hardware—or by using a virtual data buffer in software, pointing at a location in the physical memory. In all cases, the data stored in a data buffer are stored on a physical storage medium. A majority of buffers are implemented in software, which typically use the faster RAM to store temporary data, due to the much faster access time compared with hard disk drives. Buffers are typically used when there is a difference between the rate at which data is received and the rate at which it can be processed, or in the case that these rates are variable, for example in a printer spooler or in online video streaming.
