File Systems:
	 They store and retrieve files
	 What do we want out of a filesystem?
		- Fast at finding and reading and writing and creating and deleting
		- Doesn't waste space
		- Maintenence not required or easy to do
		- Doesn't lose files even if power is lost
		- Files can be recovered from bad disk
		- Doesn't hurt your hard drive
		- Supports metadata like ACL, last modified, etc.
		- Low CPU overhead (but not at the expense of speed usually)
		- Resizing!  Demo
	
What features do filesystems (sometimes) have?
	- Journaling
	- B-trees (kinda did that)
	- Parallel support (XFS, etc)
	- Expansion
	- Aging
	- Max file sizes, volume size, number of files, etc

Brief summary of some common filesystems:
	- FAT 
	- ext2/3/4
	- reiserFS / reiser4 --> btrfs
	- jfs (IBM)
	- xfs (SGI)
	- ntfs (Microsoft)
	- hfs (Apple)

ZFS:  More than just a filesystem
	Pools and filesystems
	zpool status and zfs list
	encrypted filesystem != encrypted pool

File Allocation Table:
	Originally designed for floppies
	Simple, little CPU overhead
	Dominates memory card filesystems.  Why?
		- Could be handled by camera processors 10 years ago
		- Low CPU overhead means long battery life (MP3, etc)
		- Finding is slower than other systems, but transfer rate is ok
		- Simple to program compared to alternatives
	
FAT Implementation:
	If you look this up on Google Images, use "File Allocation Table" not "FAT"
	Table Entries:
		- File Identifier
		- Directory Name
		- Location on disk
		- More (picture online)
	Limits:  4gb on fat32, etc.
		- These are implementation-dependent.
		- Clusters and small files

	Split Files:
		Cluster chains
		First and last are recorded - what if you want the middle?	

	Fragmentation and defrag

OS Support:
	All major operating systems support FAT
	Generally speaking, Windows is the only major OS that will run on FAT
		- There is always a way...
		- DOS ran on it
	No file permissions

ReiserFS:  The B-tree revolution
	- Everything goes in the tree!
	- Journaling
	- Online resizing
	- Tail packing (can hurt performance)
	- Big kernel lock

Practicality time:  Which one should you use?
	- phoronix benchmarks on 4.14
		+ sync less often - have some guts and win the race
	- So which one to use?
		+ XFS is intended for large filesystems and is solid
		+ Nobody ever got fired for using EXT4
		+ Be a filesystem nerd and have one of each

The nature of data:  Structures, strings, and arrays
	Can we make ourselves a linked data structure with just offsets?
		Yes, might take longer than we want to devote to the purpose.
		Keep free spaces in a heap or something
		Space and speed are often at odds with each other