These days, if you want to do something like this, you should check out libeatmydata. Linux has a tweakable knob called laptop_mode which is meant as an energy saving tool for laptop users on battery: it basically says “try not to touch the disk for X minutes at a time, unless you really need to, and once you do, do everything that you’ve been piling up all at once”. It’s great for laptop users, and doubly so for things like my huge laptop with two 7200RPM HDDs.
