How to store large files on Fat32

Most file archivers, such as 7-Zip, WinZip, and WinRAR, allow you to split an archive across multiple files. If speed is important, you can try disabling the compression part of the program.

On GNU/Linux systems, you can use the split and cat programs from the coreutils package (e.g. split -b 4294967295 FOO /media/FATDISK/BAR to split FOO into BARaa, BARab, ... and cat /media/FATDISK/BAR?? > FOO to reassemble it). Mac OS X's command line split utility works in the same way.

If you are looking for a quick solution to this, please see the other answers featuring 7zip or split. This is more of a fun solution.

I ended up writing a small Python 2 script to achieve this.

---

# Author: Alex Finkel 
# Email: [email protected]

# This program splits a large binary file into smaller pieces, and can also 
# reassemble them into the original file.

# To split a file, it takes the name of the file, the name of an output 
# directory, and a number representing the number of desired pieces.

# To unsplit a file, it takes the name of a directory, and the name of an 
# output file.

from sys import exit, argv
from os import path, listdir

def split(file_to_split, output_directory, number_of_chunks):
    f = open(file_to_split, 'rb')
    assert path.isdir(output_directory)
    bytes_per_file = path.getsize(file_to_split)/int(number_of_chunks) + 1
    for i in range(1, int(number_of_chunks)+1):
        next_file = open(path.join(output_directory, str(i)), 'wb')
        next_file.write(f.read(bytes_per_file))
        next_file.close()
    f.close()
                
def unsplit(directory_name, output_name):
    assert path.isdir(directory_name)
    files = map(lambda x: str(x), sorted(map(lambda x: int(x), listdir(directory_name))))
    out = open(output_name, 'wb')
    for file in files:
        f = open(path.join(directory_name, file), 'rb')
        out.write(f.read())
        f.close()
    out.close()
        
    
if len(argv) == 4:
    split(argv[1], argv[2], argv[3])
elif len(argv) == 3:
    unsplit(argv[1], argv[2])
else:
    print "python split_large_file.py file_to_split output_directory number_of_chunks"
    print "python split_large_file.py directory name_of_output_file"
    exit()

Another option: use the split command from GNU Coreutils:

split --bytes=4G infile /media/FAT32drive/outprefix

to split the file into 4 GB chunks and save the chunks to the output drive.

The original file can be recovered by concatenating the chunks (with filenames sorted alphabetically).

For usage info, see the split manual.

Coreutils, including split, should be installed by default on Linux and Mac OS X. On Windows, it's available from GnuWin32, or from Cygwin.