Free Space Management
Bit map.
- Every bit represents a block on the disk.
- 1: the block is free. 0: the block is allocated.
- Therefore, we spend 1 block of bits for every 4096*8 = 32768 blocks.
- Stored on a specific place on the disk.
- Has to be kept also in memory to be efficient.
- Special hardware support (bit operation) to find the first ‘1’ in a word if it is not zero.
- Efficient in finding consecutive blocks.