diff --git a/README.txt b/README.txt
index 97d8955a..622d90a9 100644
--- a/README.txt
+++ b/README.txt
@@ -40,10 +40,10 @@ Installation
 Upgrade from 2.3.X
 ~~~~~~~~~~~~~~~~~~
 The database connection setting in config.php has changed; now using
-PDO DSN format [1] rather than ADODB URI [2]
+PDO DSN format rather than ADODB URI:
 
- [1] <proto>:user=<username>;password=<password>;host=<host>;dbname=<database>
- [2] <proto>://<username>:<password>@<host>/<database>
+ OLD: $database_dsn = "<proto>://<username>:<password>@<host>/<database>";
+ NEW: define("DATABASE_DSN", "<proto>:user=<username>;password=<password>;host=<host>;dbname=<database>");
 
 The rest should be automatic, just unzip into a clean folder and copy across
 config.php, images and thumbs folders from the old version. This
diff --git a/core/database.class.php b/core/database.class.php
index 53ed4b4d..64123180 100644
--- a/core/database.class.php
+++ b/core/database.class.php
@@ -274,8 +274,6 @@ class Database {
 	 * stored in config.php in the root shimmie folder
 	 */
 	public function Database() {
-		global $database_dsn, $cache_dsn;
-
 		# FIXME: detect ADODB URI, automatically translate PDO DSN
 
 		/*
@@ -285,10 +283,10 @@ class Database {
 		 * http://stackoverflow.com/questions/237367
 		 */
 		$matches = array(); $db_user=null; $db_pass=null;
-		if(preg_match("/user=([^;]*)/", $database_dsn, $matches)) $db_user=$matches[1];
-		if(preg_match("/password=([^;]*)/", $database_dsn, $matches)) $db_pass=$matches[1];
+		if(preg_match("/user=([^;]*)/", DATABASE_DSN, $matches)) $db_user=$matches[1];
+		if(preg_match("/password=([^;]*)/", DATABASE_DSN, $matches)) $db_pass=$matches[1];
 
-		$this->db = new PDO($database_dsn, $db_user, $db_pass);
+		$this->db = new PDO(DATABASE_DSN, $db_user, $db_pass);
 		$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 
 		$db_proto = $this->db->getAttribute(PDO::ATTR_DRIVER_NAME);
@@ -305,9 +303,8 @@ class Database {
 			die("Unknown PDO driver: $db_proto");
 		}
 
-		if(isset($cache_dsn) && !empty($cache_dsn)) {
-			$matches = array();
-			preg_match("#(memcache|apc)://(.*)#", $cache_dsn, $matches);
+		$matches = array();
+		if(CACHE_DSN && preg_match("#(memcache|apc)://(.*)#", CACHE_DSN, $matches)) {
 			if($matches[1] == "memcache") {
 				$this->cache = new MemcacheCache($matches[2]);
 			}
diff --git a/core/util.inc.php b/core/util.inc.php
index 97146d25..21343497 100644
--- a/core/util.inc.php
+++ b/core/util.inc.php
@@ -204,7 +204,7 @@ function make_link($page=null, $query=null) {
 
 	if(is_null($page)) $page = $config->get_string('main_page');
 
-	if(FORCE_NICE_URLS || $config->get_bool('nice_urls', false)) {
+	if(NICE_URLS || $config->get_bool('nice_urls', false)) {
 		#$full = "http://" . $_SERVER["SERVER_NAME"] . $_SERVER["PHP_SELF"];
 		$full = $_SERVER["PHP_SELF"];
 		$base = str_replace("/index.php", "", $full);
diff --git a/index.php b/index.php
index 63c3b52c..29cbecca 100644
--- a/index.php
+++ b/index.php
@@ -57,18 +57,23 @@ if(empty($database_dsn) && !file_exists("config.php")) {
 require_once "config.php";
 
 // set up and purify the environment
-if(!defined("DEBUG"))           define("DEBUG", false);
-if(!defined("COVERAGE"))        define("COVERAGE", false);
-if(!defined("CONTEXT"))         define("CONTEXT", false);
-if(!defined("CACHE_MEMCACHE"))  define("CACHE_MEMCACHE", false);
-if(!defined("CACHE_DIR"))       define("CACHE_DIR", false);
-if(!defined("CACHE_HTTP"))      define("CACHE_HTTP", false);
-if(!defined("VERSION"))         define("VERSION", 'trunk');
-if(!defined("SCORE_VERSION"))   define("SCORE_VERSION", 's2hack/'.VERSION);
-if(!defined("COOKIE_PREFIX"))   define("COOKIE_PREFIX", 'shm');
-if(!defined("SPEED_HAX"))       define("SPEED_HAX", false);
-if(!defined("FORCE_NICE_URLS")) define("FORCE_NICE_URLS", false);
-if(!defined("WH_SPLITS"))       define("WH_SPLITS", 1);
+function _d($name, $value) {
+	if(!defined($name)) define($name, $value);
+}
+_d("DATABASE_DSN", null);    // string   PDO database connection details
+_d("CACHE_DSN", null);       // string   cache connection details
+_d("DEBUG", false);          // boolean  print various debugging details
+_d("COVERAGE", false);       // boolean  activate xdebug coverage monitor
+_d("CONTEXT", null);         // string   file to log performance data into
+_d("CACHE_MEMCACHE", false); // boolean  store complete rendered pages in memcache
+_d("CACHE_DIR", false);      // boolean  store complete rendered pages on disk
+_d("CACHE_HTTP", false);     // boolean  output explicit HTTP caching headers
+_d("COOKIE_PREFIX", 'shm');  // string   if you run multiple galleries with non-shared logins, give them different prefixes
+_d("SPEED_HAX", false);      // boolean  do some questionable things in the name of performance
+_d("NICE_URLS", false);      // boolean  force niceurl mode
+_d("WH_SPLITS", 1);          // int      how many levels of subfolders to put in the warehouse
+_d("VERSION", 'trunk');      // string   shimmie version
+_d("SCORE_VERSION", 's2hack/'.VERSION); // string SCore version
 
 require_once "core/util.inc.php";
 require_once "lib/context.php";
diff --git a/install.php b/install.php
index 83a1f2f3..e5f2e5cc 100755
--- a/install.php
+++ b/install.php
@@ -52,7 +52,7 @@ if(is_readable("config.php")) {
 			<h1>Shimmie Repair Console</h1>
 <?php
 	include "config.php";
-	if($_SESSION['dsn'] == $database_dsn || $_POST['dsn'] == $database_dsn) {
+	if($_SESSION['dsn'] == DATABASE_DSN || $_POST['dsn'] == DATABASE_DSN) {
 		if($_POST['dsn']) {$_SESSION['dsn'] = $_POST['dsn'];}
 
 		if(empty($_GET["action"])) {
@@ -350,7 +350,9 @@ function build_dirs() { // {{{
 } // }}}
 function write_config() { // {{{
 	global $database_dsn;
-	$file_content = "<?php \$database_dsn='$database_dsn'; ?>";
+	$file_content = "<"+"?php\n"+
+	"define('DATABASE_DSN', '$database_dsn');\n"+
+	"?"+">";
 	
 	if(is_writable("./") && file_put_contents("config.php", $file_content)) {
 		assert(file_exists("config.php"));