Question: Why does OS X insist on spinning up all the attached external drives (firewire, usb) when loading a file from the local (internal) drive?
It’s driving me insane that I have to wait for 3 attached drives (1 back-up, 2 media) to spin up — a total of 20s — to access a file that is located only on my local/internal drive. There is no obvious need to access the other drives; nothing is being read from them and nothing need be written.
Examples: Quicktime X opening a file from the local HDD. Starting Caffeine, an app which doesn’t access any other files at all.
Can I tell OS X to only spin those drives up when actually accessing them?
Answer: If by “access” you mean perform I/O operations on a file, then that should not be happening. If by “access” you mean that you’re bringing up the standard Open/Save dialogs, then you are actually hitting those filesystems whether you realize it or not.