diff --git a/README.md b/README.md
index 82d78944..ecc9e239 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,7 @@ Basic requirements:
 A computer running a Unix or Unix-like OS(infinity has been specifically tested with and is known to work under Ubuntu 14.x), Apache, MySQL, and PHP
 * Make sure Apache has read/write access to the directory infinity resides in.
 * `install.php` is not maintained. Don't use it.
+* As of February 22, 2015, you need the [DirectIO module (dio.so)](http://php.net/manual/en/ref.dio.php).
 
 Step 1. Create infinity's database from the included install.sql file. Enter mysql and create an empty database named 'infinity'. Then cd into the infinity base directory and run:
 ```
diff --git a/inc/functions.php b/inc/functions.php
index 57d91cbb..44666b83 100755
--- a/inc/functions.php
+++ b/inc/functions.php
@@ -549,29 +549,27 @@ function file_write($path, $data, $simple = false, $skip_purge = false) {
 		}
 	}
 
-	if (!$fp = fopen($path, $simple ? 'w' : 'c'))
+	if (!$fp = dio_open($path, O_WRONLY | O_CREAT, 0644))
 		error('Unable to open file for writing: ' . $path);
 
 	// File locking
-	if (!$simple && !flock($fp, LOCK_EX)) {
+	if (dio_fcntl($fp, F_SETLKW, array('type' => F_WRLCK)) === -1) {
 		error('Unable to lock file: ' . $path);
 	}
 
 	// Truncate file
-	if (!$simple && !ftruncate($fp, 0))
+	if (!dio_truncate($fp, 0))
 		error('Unable to truncate file: ' . $path);
 
 	// Write data
-	if (($bytes = fwrite($fp, $data)) === false)
+	if (($bytes = dio_write($fp, $data)) === false)
 		error('Unable to write to file: ' . $path);
 
 	// Unlock
-	if (!$simple)
-		flock($fp, LOCK_UN);
+	dio_fcntl($fp, F_SETLK, array('type' => F_UNLCK));
 
 	// Close
-	if (!fclose($fp))
-		error('Unable to close file: ' . $path);
+	dio_close($fp);
 
 	/**
 	 * Create gzipped file.