Overhead of folders when burning?

Hi there!

I’ve just created a program called SizeMe: http://lars.werner.no/sizeme/

It tries to fill each disc as much as it can with the content selected. Now I’ve some feedbacks from users that some 100% discs aren’t burned, and I’ve found out that the “overhead” in each disc makes it a noch to big.

I wonder if someone have a complete overview of what “overhead” of each element. Is a directory 2048 bytes big? Or what is real value.

Are there other overheads that needs to be in the calculation?

Best Regards
Lars Werner

BTW: Try also http://lars.werner.no/unpacker/

I’ve found out that there is a overhead of about 4k on each directory added to a joilet compilation on a iso9660 compilation, is that accurate?

It’s kind of HelpMe bundled with advertising. Dunno. Thoughts.

I’d leave it. It appears a genuine request for help and it is freeware as far as I can tell…so I’d allow it.

you dont wanta burn all the way to the edge cuz sometime it could cause some major problem on reading it.

I’ve never had any problems with filling a disc up to its max.

I wonder if someone have any documentation of the overhead for a standard iso9660 joilet cd compilation? Do you know?

You can try and search that at google, you should get at least soemthing.

I have of course tried to search google, but there aren’t any clear good lists over what items and structures that makes overhead on a compilation.

My guess is that people here doesn’t know the answer which is fair, since it is quite special :slight_smile:

yup :iagree:

For ISO-9660 all file and folder names are stored contiguously. This means that one sector (2048 bytes) will contain several file or folder names. The size of each entry depends on the length of the file or folder name. File ‘data’ on the otherhand always occupies complete sectors. Even if the file is only 48 bytes big, it still needs 2048 bytes of space on a CD. I’m not sure about Joliet.

Thnx for the reply. That made some sense! I wonder if you have any good articles about the ISO-9660 filesystem. By searching with google I only get stuff that are irrlevant for my case.

If what you’re saying is correct I can sum up the total length of text under a directory (recursive) and I’ll get the overhead? Or does it has a default overhead when created?


Here is a link to ECMA-119 which is the equivalent to ISO-9660.

As you will see in the PDF, each directory and file name has several bytes of overhead. So, you will not be able to simply count all the letters that make up your directory and file names. It may seem a little overwhelming at first, but once you get a basic understanding of how it all works it’s not so bad.

Remember that every file ends on a sector boundary even if most of the last sector is all zeroes (unused space).

Another thing to understand is that no data is stored on the disc before 00:02:16. This is where the ISO file system starts being defined. The first sector (00:02:16) is the PVD (primary volume descriptor). You can use that info as a reference while reading the PDF to see what is stored there and what comes next. Good luck.