 |
| Record stored on tapes: |
Record stored on tapes can be of varying lengths, if a tape contains a large number of very shorts records with an IRG after each record. more than half of the tape could be unused occupied with (IRGs), moreover, the tape I/O operation would also be very slow. due to very frequent interruption in tape movement during I/O operations, To overcome these problems of inefficient usage of tape storage space. and inefficient I/O operation. records are usually grouped in blocks of two or more separated by an inter block gap IBG the process of grouping two or more records together, to form a block of data is known as blocking. and the number of record put together in each block. is called blocking factor, the blocking factor generally depends on the record length. the rule of thumb for deciding blocking factor is that the block should be at least ten times as long as the IBG. to reduce wastage of tape storage space.