Why are FAT32 disks limited to 4GB files?

filesystems fat32 filesize
user5243421 picture user5243421 · Jan 11, 2011 · Viewed 31.7k times · Source

I'm not looking for a workaround; I'd like an explanation. Most of the links I found through Google just tell me that the file limit is 4GB, but not why.

I am aware of the explanation by Wikipedia: http://en.wikipedia.org/wiki/File_Allocation_Table#FAT32

But this still does not go into detail about why. (What does SCANDISK have to do with it?)

Maybe then I will understand whether it's possible to overcome the 4GB file size limit.

Answer

Fred Foo picture Fred Foo · Jan 11, 2011

Because FAT32 stores 32-bit file sizes and the maximum you can store in 32 bits is 2^32-1 ~= 4.29e9. 2^32-1 bytes = 4GB - 1 byte.

(This is, in fact, explained in the Wikipedia article.)

Related questions

What is the difference between VFAT and FAT32 file systems?

I have searched the internet, but could not find any convincing answers; Are the filesystems VFAT and FAT32 the same, or are there any differences between them?

Read More
Filesystem links on a FAT32 formatted storage

I know FAT32, as well as FAT16/12 neither support symbolic links nor hard-links. However I came up with this idea: The FAT specification describes that every file is associated with a directory-entry. In my understanding, one could say that a …

Read More
2GB limit on file size when using fwrite in C?

I have a short C program that writes into a file until there is no more space on disk: #include <stdio.h> int main(void) { char c[] = "abcdefghij"; size_t rez; FILE *f = fopen("filldisk.dat", "wb"); while (1) { …

Read More