after GC
assume
- free space starts at 140
- then free and scan start at 140
- and end at 164
result is
- 100: F148 140: P148
- 104: P132 144: P156
- 108: F156 148: N008
- 112: P100 152: P140
- 116: N007 156: N006
- 120: P108 160: P148
- 124: N004 164:
- 128: P116 168:
- 132: F140 172:
- 136: P108 176:
(draw this as a box and pointer diagram)