---

1. Fragmentation

---

2. Cylinder Groups

---

3. Block Groups

in each group

keep related stuff together, unrelated stuff far apart

balance allocation of directories

allocate file data in same group as inode and directory

---

4. Examples

Using ffs.py:

$ cat in.example1

dir /a
dir /b
file /a/c 2
file /a/d 2
file /a/e 2
file /b/f 2

$ python ./ffs.py -f in.example1 -c -d 10

group inodes     data
    0 /--------- /---------
    1 acde------ accddee---
    2 bf-------- bff-------
    3 ---------- ----------
    4 ---------- ----------
    5 ---------- ----------
    6 ---------- ----------
    7 ---------- ----------
    8 ---------- ----------
    9 ---------- ----------

$ python ./ffs.py -f in.example1 -c -d 10 -I

group inodes     data
    0 /--------- /---------
    1 a--------- a---------
    2 b--------- b---------
    3 c--------- cc--------
    4 d--------- dd--------
    5 e--------- ee--------
    6 f--------- ff--------
    7 ---------- ----------
    8 ---------- ----------
    9 ---------- ----------

---

5. Large Files

$ cat in.example2

file /a 30

$ python ./ffs.py -f in.example2 -c

group inodes     data
    0 /a-------- /aaaaaaaaa aaaaaaaaaa aaaaaaaaaa
    1 ---------- a--------- ---------- ----------
    2 ---------- ---------- ---------- ----------
    3 ---------- ---------- ---------- ----------
    4 ---------- ---------- ---------- ----------
    5 ---------- ---------- ---------- ----------
    6 ---------- ---------- ---------- ----------
    7 ---------- ---------- ---------- ----------
    8 ---------- ---------- ---------- ----------
    9 ---------- ---------- ---------- ----------

$ python ./ffs.py -f in.example2 -c -L 4

group inodes     data
    0 /a-------- /aaaa----- ---------- ----------
    1 ---------- aaaa------ ---------- ----------
    2 ---------- aaaa------ ---------- ----------
    3 ---------- aaaa------ ---------- ----------
    4 ---------- aaaa------ ---------- ----------
    5 ---------- aaaa------ ---------- ----------
    6 ---------- aaaa------ ---------- ----------
    7 ---------- aa-------- ---------- ----------
    8 ---------- ---------- ---------- ----------
    9 ---------- ---------- ---------- ----------