关于php memory_limit

My system memory is 128M and set memory_limit to 128M, can use php fread to download files over 150M size? I tried not! Can be downloaded only 110M around!

thanks all,

    $sent = 0;
    $blocksize=(2 << 20);

    $fp = fopen($download_path, "rb");
    while($sent < $size){
        echo fread($fp, $blocksize);
        $sent += $blocksize;
    }
    exit(0);

I use this way, so how should I do?

Yes, if you don't try to read them all into memory in entirety. You should read your files in chunks and handle those chunks one at a time, if your requirements allow you to. This is just generally a good idea, no matter what you're doing and no matter how much RAM you have.