Total size inconsistency

[DanL]

OK, when I "Get Info" on my disk icon, I get 73 GB used. When the finder displays all the folders on that disk, it adds up to 66 GB. What's taking up the extra 7 GB?

 

[Lufbrarunner]

The way in which the data is stored on the drive means that it will be space left i.e. if the HD stores data in say 512kb blocks and only 400kb is used there is 112kb that is marked as used and although the space is free it is not usable. All these small bits will add up. plus there will be other stuff taking up space for instance the disk needs to map where files begin and end etc
It's a bit of a simplistic explanation, but I am sure someone will be along with a more detailed explanation in due course.

 

[DanL]

I'm used to having less space available than advertised, because of "housekeeping" stuff. But 7 GB?

 

[Cory Cooper]

Hello,

The "missing" GBs are probably files in the hidden folders in you user Library folder, the root Library folder, and the System folder.

Apps like GarageBand store their instruments and sound loops in these folders, and the MacBook family stores a swapfile and temporary files in hidden folders.

You could use and app like OmniDiskSweeper or WhatSize, which can see the hidden folders and that should account for the missing 7 GB.

C

 

[DanL]

Ah, so when Finder reports sizes, it ignores "hidden folders"? Why should it do that? If I want to know the size of my whole system, for example to decide if I can fit it on a partition, Finder won't give it to me? That's interesting that I have to pay money for an app to tell me how big my file system is.

 

[DanL]

OK, the answer is that Get Info reports a size of *everything*, including swap files, sleep images, temporary files, etc.The file/folder list in Finder does not. So Finder DOES give you the whole size, but just via Get Info, or Disk Utility.

 

[Cory Cooper]

Yes, I agree that it could be represented better.

OmniDiskSweeper is free if you want to try it out.

C