Exercise 15.1: Comparing I/O Schedulers

Good point. It will not restore your previous state, but you can do that with a one line command. The script could have been done to do this, but it would have required a bunch of extra lines that are a little messy to write and debug since people use it for different systems with different default schedulers etc and once you start to complicate scripts it gets hard to see the forest for the trees. At any rate system reboot wipes all this out since it is purely runtime behaviour and resets, and it is unlikely you would notice any differences between schedulers unless you were running a heavy I/O workload on a server for a prolonged time. With the changes in storage media these days most folks don't care much about this topic any more except in rather specialied situations where it can still really matter. Attention on it is now defocused.