Memory_limit in php.ini
 

I wrote a php script for upload of files and it works OK.

However, now I plan to tweak it to accept larger files (200M+), too, but somewhere I read that variable "memory_limit" in php.ini must exceed the size of the file to be uploaded, which would be a great restriction for me.

I doubt that there should be any such relation between these two values, as it would be rather clumsy (no large file uploads possible on a server that is short of RAM?), especially that the uploaded files seem to be temporarily stored on disk by php (in a temporary file in /tmp).

Could you confirm that the value of "memory_limit" in php.ini must really exceed the size of the file to be uploaded, and why?
If so, is there a workaround for web servers that are in short of RAM?