In the dictionary, it says "We need to delete more files to free (up) space on the computer's hard drive.".

My question is that

Why not "in the hard drive"?

There are electric circuits or magnetic stuff in a computer's hard drive. I guess "free up space in a hard drive" means to remove electric circuits or magnetic stuff on platter in it, which doe snot make any sense.

So, I guess "hard drive" here means logical hard drive like an application not a physical one.

We often use on with an app, for example, "on my computer" not "in my computer" if we think "computer" is an app not a physical computer.

This is what I guessed but I might get it wrong.

But I guess we say "free up space in your computer's memory"

Is it correct to say?:

"you can free up space in your computer's hard drive"

"you can free up space on your computer's hard drive"

"you can free up space in your computer's memory"

  • 3
    I don't know where the conventions came from (perhaps Jack's answer has it right), but I do know that there is a right word and a wrong word to use. It is emphatically true that there is space on the hard drive and items in memory (or storage).
    – randomhead
    Commented Oct 11, 2021 at 3:54
  • 2
    Also note that "storage" refers to data on the hard drive while "memory" refers to RAM... it is incorrect to say that a file "has been saved to memory" because memory is ephemeral.
    – randomhead
    Commented Oct 11, 2021 at 4:01
  • Historically you might store data on a single side of single disk, so "on" made sense. Modern hard drives have multiple disks and write heads, and solid state drives don't have any disk surface, so they're no longer flat things with a single surface you write on, but "on" has stuck as the usual preposition.
    – Stuart F
    Commented Jul 24, 2023 at 11:04

1 Answer 1


It depends on whether you are using a 3-dimensional (volume) metaphor (in) or a 2-dimensional (surface) metaphor (on).

Hard drives, at least the rotating type, use surfaces of platters (albeit to a certain depth) to store magnetic information.

Maybe that is where the terminology "on the drive" arose.

"In the memory" may be a better fit for semiconductor memory that has no obvious moving parts or surfaces.

  • "free up space in your computer's memory" because it refers to a portion of memory within the total available memory. It's in there.
    – user3169
    Commented Oct 11, 2021 at 4:22
  • You could use the same argument of a hard drive. Commented Oct 11, 2021 at 5:11
  • 1
    You could, but I think "on" is standard due to the disk surface.
    – user3169
    Commented Oct 11, 2021 at 16:55
  • It might even be a carry-over from magnetic tape. Commented Nov 12, 2021 at 7:55
  • 1
    Semiconductor memory doesn't have moving parts (unless you count electrons) but it does have a surface. All of the components that make up the semiconductor memory is etched or deposited onto the surface of a piece of silicon. That said, the surface analogy is weak: you write 'on' paper but 'in' a book and both activities involve surfaces.
    – JavaLatte
    Commented Mar 16, 2022 at 14:16

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