Index: wp-includes/default-constants.php
===================================================================
--- wp-includes/default-constants.php	(revision 22524)
+++ wp-includes/default-constants.php	(working copy)
@@ -73,13 +73,24 @@
 	if ( !defined('SHORTINIT') )
 		define('SHORTINIT', false);
 
-	// Constants for expressing human-interval intervals
+	// Constants for expressing human-readable intervals
 	// in their respective number of seconds.
  	define( 'MINUTE_IN_SECONDS', 60 );
  	define( 'HOUR_IN_SECONDS',   60 * MINUTE_IN_SECONDS );
  	define( 'DAY_IN_SECONDS',    24 * HOUR_IN_SECONDS   );
 	define( 'WEEK_IN_SECONDS',    7 * DAY_IN_SECONDS    );
  	define( 'YEAR_IN_SECONDS',  365 * DAY_IN_SECONDS    );
+
+	// Constants for expressing human-readable data sizes
+	// in their respective number of bytes.
+	define( 'KB_IN_BYTES', 1024 );
+	define( 'MB_IN_BYTES', 1024 * KB_IN_BYTES );
+	define( 'GB_IN_BYTES', 1024 * MB_IN_BYTES );
+	define( 'TB_IN_BYTES', 1024 * GB_IN_BYTES );
+	define( 'PB_IN_BYTES', 1024 * TB_IN_BYTES );
+	define( 'EB_IN_BYTES', 1024 * PB_IN_BYTES );
+	define( 'ZB_IN_BYTES', 1024 * EB_IN_BYTES );
+	define( 'YB_IN_BYTES', 1024 * ZB_IN_BYTES );
 }
 
 /**