32 bit file sizes in Apache HTTPD

Today I backed up some files from my Powerbook to a DVD image. Once I created the DVD image I was going to transfer it to my PC which is the home of my burner. How shall I transfer the file?

Via SMB? Nope. I've had very little success with SMB in the past, and I think it's slow

Via FTP? Nope. The Windows FTP command sucks wind.

Via HTTP? Sure! My Mac has Apache built-in, and then I can download with my browser. This combination might even support resume if the transfer is interrupted.

I dumped the DVD image in my ~/Sites/ folder, which is the Mac-equivalent of ~/public_html. But when I viewed that directory from my PC, the 4.37 GB file morphed into a 386 MB file. What the heck?

And now a math lesson. My file was 4.37 GB. More precisely: 4699488256 bytes. And unfortunately for me, 4699488256 > (2³²). In fact, 4.37 GB mod (2³²) = 386 MB.

Lesson learned? Apache file sizes are 32-bit. Don't transfer anything larger than 4 GB over the web!

# posted by Jesse Wilson on Wednesday, February 02, 2005