Suppose we have only 320 words of memory
x1 = alloc(32) x2 = alloc(32) ... x10 = alloc(32) free(x1, 32) free(x3, 32) free(x5, 32) free(x7, 32) free(x9, 32) // now have 160 bytes of free memory z = alloc(50) // fails!
Our memory starts to look like the Rolex Learning Center!
Some steps to address this:
- always merge adjecent blocks (e.g. suppose there was free(x4,32) )
- not sufficient in general
- in general must do compaction (move blocks to put them together)