Weird file sizes in Finder

Ok, here's an initial finding when re-downloading LibreOffice for the update:

LibreOffice in DMG: 437 MB
on hard drive: 437 MB
duplicate on hard drive: 384.4 MB.

Ok.. I just checked something else and this made my head spin. Get Info on those two copies verifies the above numbers. Specifically, 437,024,990 bytes vs 384,436,781 bytes. BUT!….

If I open the package to view contents, then Get Info on the Contents folder…. they BOTH say 437 MB, specifically 437,024,990 bytes. On BOTH copies! Like it should be all along. So why the heck is Finder reporting the duplicated .app to be smaller than its contents???? Is there some sort of compression going on when it makes a copy? I'll recheck those sizes tonight to see if it changes over time, though I'm skeptical.

Well, it would seem that this anomaly is consistent across machines (unless slapple is also pacoverflow at superuser). This person noticed a file size discrepancy that corresponds to slapple's: Xcode installer and the copy, along with GarageBand and its copy, are the same sizes as slapple's. It also seems to happen with directories and not just bundles (therefore, it's not something special about bundle directories).

I just tried it on a directory and had similar results in a directory with app bundles that had been copied: I realize the difference is tiny but still apparent.

However, I did this for a directory where an app bundle hadn't been copied and the sizes were identical:

Dysfunction said:

No, du reported that the copy was almost twice the size for the cp -rp method.

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Oh, I didn't see your edit when I replied. So "du" might have worked fine in that instance. But vansmith and I have seen problems with it.

lifeisabeach said:

It looks to me like Finder is adding some sort of metadata inside the directory structure of apps (after all, apps are really special folders), and copy/pasting the app doesn't include that metadata.

Click to expand...

lifeisabeach said:

So why the heck is Finder reporting the duplicated .app to be smaller than its contents???? Is there some sort of compression going on when it makes a copy?

Click to expand...

I'm not sure that the duplicates are missing metadata or are being compressed. I already used DeltaWalker to compare the originals and duplicates, and they are exactly the same... unless DeltaWalker is ignoring any metadata.

But what's weird for me is that Finder reports all the duplicates to be smaller than the originals, but "du" reports all the duplicates to be larger than the originals!

vansmith said:

(unless slapple is also pacoverflow at superuser).

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Yeah, that's me.

vansmith said:

I just tried it on a directory and had similar results in a directory with app bundles that had been copied:

Code:

~ :: du -sk Applications_copy/
644096	Applications_copy/
~ :: du -sk Applications
643856	Applications

I realize the difference is tiny but still apparent.

Click to expand...

Doesn't matter that the difference is tiny. The point is on a copy there shouldn't be any difference at all.

slapple said:

Doesn't matter that the difference is tiny. The point is on a copy there shouldn't be any difference at all.

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Agreed. I was simply pointing out the fact that the differences don't seem to be consistent in that one moment they're huge and the next they're tiny.