Why is the backup a different size than the original

I’ve been scrupulously backing up my novel since day one. I’ve been archiving them in Zip format, and I noticed today that even though the size of the file has changed a lot, the size of the Zip has stayed relatively static and small — a few hundred kb. Hmmm.

So today I unpacked one of the recent Zip archived versions, and the file ballooned to 3.2mb.
No problem there, except that the file that I’m working on, and backing up, is only 1.1mb. So now I’m confused.

I decided to back up the project again, and this time to save it as a Scrivener file. Again, the file is saved as a 3.2mb file.

There must be something about this process that I’m missing. But why is the backup three times bigger than the original?


Try ctrl-clicking on the original in the Finder and doing a Get Info, and checking the file size there. It may be that Finder is just reporting the file size wrong.
All the best,

Well, Get Info says the same thing. 3.2 MB for the backup, 1.1 MB for the original.

Try ctrl-clicking on each file and selecting “Show Package Contents” to peer inside the files. That way you can see if the bigger file contains files that the other does not. (Also try getting info on the unzipped backup, to check the size of that is reported correctly, of course.)

Okay, I did a show package contents and here’s the result. I pushed these finder windows close together so you could compare. The backup is consistently bigger and strangely consistent in its sizes. Hope this offers some clue…

Just for giggles do a diff on the two projects from a terminal window. I wonder if zip is just 0 padding the files for easy block writes.

Jaysen, sorry, that’s probably good advice but I’m not tech savvy enough to follow you. How do I do a diff from the terminal window?

Assuming Project.scriv and BackUp.scriv for names. Assuming both files live in Documents.

Go to Applications, Utilities and double click on Terminal. In the terminal window type:

cd Documents
diff Project.scriv BackUp.scriv > differences.txt

This will create a file in Documents called differences.txt that will contain all the differences between the two files. It will probably be daunting at first look, but once you understand what it is saying you might find that you really like diff.

Take a look at the file and look for something lots of white space. Hmm… It might show up as something like “binary file XX.XXX differs”

If your files are not in the same directory or have spaces in their names PM me the path and name and I can put construct the right diff line for you.

That’s a good point. Are you using any special tool to do the unzipping? Try creating a folder in Finder with a few text files in it, then zip it up and unzip it again - do you see similar results there too? My guess is that this has to do with your unzip tool.

Hey you! Stop making things easier!

Just out of curiosity, are your backups stored on one disk and your working files stored on another disk entirely? I concur with Jaysen, this does appear to be a block size issue. It is unusual to see anything over a 4096 block size on a Mac (outside of video applications), but it seems odd that you have so many 64kb files.

In Terminal, you could use: ls -lh in each project and see if those sizes match. That will return actual data size, not block usage.

Or you could just drag the backup project to the primary disk and see if they match, then. Of course, if this is all on one disk none of this applies and it is probably the zip issue above.

WOOHOO!!! Validation!

One of these days i really need to consider that whole “maturing” thing.

Amber wins!!

I was indeed storing my backups on a different drive – a flash drive.

So this time I tried backing up to the same drive as the original, just a different folder. This time, the file size was identical.

I’m relieved. Thanks Amber, and thanks Jaysen and Keith for your help.

Just for the sake of “I am not entirely wrong” is that flash drive M$ formatted? Meaning that you can use it on a Mac or Windows machine right now. Or meaning that you have not formatted it HPFS+ using disk utility.

Yes. It’s formated MS-DOS (fat-16)

I left it that way because I was having trouble using other flash drives on a windows computer I needed to use occasionally.

So, my question is, is there anything wrong, per se, with the backups on this drive? Could I use one of them as my new version if I had to, or cut and paste material from one of them to the working file?

Or should I reformat it to Mac OS Extended and bite the bullet on the lost backups?

That makes me feel a little better.

You should be fine. What you are seeing is a file size reporting anomaly. You should be able to copy the backup from the flash drive to the local drive then decompress. If you were already using this method then I suspect you are doing the “Backup To” directly to the flash.

I’ve actually been planning to ask about if it would be better to save a backup directly to an external drive, or to save it to disk then copy over, and this entire situation answers that. Thanks!