Mildly OT Hard Drive File Management

Just when I thought I had this nailed.

We had a bunch of files to transfer between a MS-DOS [FAT32] external hard drive and a full-on MacOS Extended, Journaled external hard drive.

The files came over slightly different sizes, although they seemed to be correct and undamaged in every other way.

I'm putting this down to differences in file allocation tables and cluster sizes, not system damage.

Am I delusional--about this I mean?

Koz

Are you looking at the "KB" (or "MB" numbers, or do both machines display the exact number of bytes? If the former, you could attribute it to the old K=1000/1024 issue, but you've probably already considered that. Otherwise, I'd attribute it to cluster size and file management schemes. Can you experiment with a file whose contents are easily verifiable and compare how it reads on both machines?

Delusion is all in your mind....

Scott

<<<K=1000/1024 >>>

We assume both filesystems are digital.

<<<Can you experiment with a file whose contents are easily verifiable and compare how it reads on both machines? >>

A Word or Excel or Picture file works just as well from either drive. We checked carefully to make sure we didn't transfer something into the Land of Trash. Each file size is subtly different. I didn't write down the numbers and the client has the MS-DOS drive with her.

The file systems are so different I wonder if some of the difference might be that FAT32 has to keep two versions of the filename--short and long versions. Something like that. She's coming back so I can accurately compare the numbers. I never had this happen before. I've had drives that had hidden System Files that threw the numbers off, but nothing like this.

Koz

This recalls the situation you had a few months ago where one version of OS X reported file sizes differently from another version of OS X.

I'm suspecting that it's all due to how each file system manages things, and the overheads are different. Are differences generally proportional among large and small files, e.g., 1.01 times the size between systems, regardless of file size, or can you account for it by an offset that is more or less constant no matter the file size (would support the 2 versions of file name idea).

The real test is do the files "work" for each system? I'm guessing real time video might have a problem, but maybe nothing else. How critical is your work in this context?

Scott