Spooling is an acronym for Simultaneous Peripheral Operations On - Line.
Data read from / written to an input / output device is temporarily stored in a buffer area in memory or on a separate disk. When a job requires the data, it is fetched directly from the buffer area instead of initiating input / output processes, making the entire read / write process faster. This is because the speeds of mechanical I/O devices is far slower than the speed of CPU.
Before the concept of spooling, data was read (input phase), similar jobs were processed in CPU (processing), output was generated (ouptut phase). During the input and output phase (which took a long time due to the mechanical nature of I/O devices), the CPU was mostly idle, thereby decreasing the efficiency of the entire system. To reduce CPU idle time, entire data was stored in a temporary buffer, either in memory or a separate storage area like disk. Fetching data from the buffer was significantly faster than reading directly from an input device. This process is called spooling.
Wednesday, 18 February 2015
