Question

After the disk partition is first formatted, the beginning of a free space bitmap looks like this: 1000 0000 0000 0000 (the first block is used by the root directory). As we discussed during the lecture, the system always searches for free blocks starting at the lowest numbered block, so after writing file A, which uses six blocks, the bitmap would change to 1111 1110 0000 0000... . Show the bitmap after each of the following actions: a) File B is written, using five blocks; 3 b) File A is deleted; c) File C is written, using eight blocks; d) File B is deleted.

Answer 1

1000 0000 0000 0000 - (Initial state of bit-map)

1111 1110 0000 0000... (after writing file A. mentioned in question)

now

a) File B is written, using five blocks

1111 1111 1111 0000

b) File A is deleted

1000 0001 1111 0000

c)  File C is written, using eight blocks

1111 1111 1111 1100 (see here, to insert 8 blocks it will re-use 6 block before B, and remaining(8-6=2)block after file B)

d) File B deleted

1111 1110 0000 1100