Notes
- Fast Filing System (FFS)
- 1984 BSD
- Operated ~4% of hypothetical peak efficiency (yikes)
- 3BSD
- Better layout
- Locality
- Keep metadata closer to the data
- Keep files in a directory closer together
- Prevent file fragmentation
- Increase disk block size
- (Well that sounds familiar)
- Faster & fewer I/Os
- Keep more packed pointers together
- Innovations
- Physical layout: cylinder-head-sector (CHS)
- Understood processor speed & disk rotational speed
- Disk interleaving factors, when the disk is spinning vs CPU is working
- Faster CPU = lower interleaving
- Logical blocks made of multiple physical blocks
- Directory layout
- Directories need to use the cylinders
- Many algorithms, but they tended to degrade if the disk was more than 90% full
- Symlinks
- Limited number of hardlinks
- Quotas
- User and group storage limits
- Shared & exclusive locks