By soft downloaded, I mean PHP reads the file from outside of the web document directory and then "softly" render the download of the file by readfile() function. You know what I mean.
Anyway, it seems I can only provide download this way of files that are no more than 40MB in size. I tried to add set_time_limit(), it doesn't work.
So I suspect that my host may have some limitations somewhere in place. In what way can they do that? In PHP.ini or apache2.conf? Except cutting the files into smaller chunks, is there any other way I can circumvent this?