diff --git a/critbit b/critbit
index dfe57a077..934c2dd94 160000
--- a/critbit
+++ b/critbit
@@ -1 +1 @@
-Subproject commit dfe57a077222c6b572da61a79dc0687f81c10055
+Subproject commit 934c2dd94d41da19637a76a1a8b3dfeb7aa8524d
diff --git a/src/kernel/config.c b/src/kernel/config.c
index 14ca56242..b231ad7c6 100644
--- a/src/kernel/config.c
+++ b/src/kernel/config.c
@@ -1024,32 +1024,61 @@ void init_locale(struct locale *lang)
 }
 
 typedef struct param {
-    struct param *next;
-    char *name;
-    char *data;
+    critbit_tree cb;
 } param;
 
+size_t pack_keyval(const char *key, const char *value, char *data, size_t len) {
+    size_t klen = strlen(key);
+    size_t vlen = strlen(value);
+    assert(klen + vlen + 2 + sizeof(vlen) <= len);
+    memcpy(data, key, klen + 1);
+    memcpy(data + klen + 1, value, vlen + 1);
+    return klen + vlen + 2;
+}
+
+void set_param(struct param **p, const char *key, const char *value)
+{
+    struct param *par;
+    assert(p);
+
+    par = *p;
+    if (!par && value) {
+        *p = par = calloc(1, sizeof(param));
+    }
+    if (par) {
+        void *match;
+        size_t klen = strlen(key) + 1;
+        if (cb_find_prefix(&par->cb, key, klen, &match, 1, 0) > 0) {
+            const char * kv = (const char *)match;
+            size_t vlen = strlen(kv + klen) + 1;
+            cb_erase(&par->cb, kv, klen + vlen);
+            ++global.cookie;
+        }
+    }
+    if (value) {
+        char data[512];
+        size_t sz = pack_keyval(key, value, data, sizeof(data));
+        if (cb_insert(&par->cb, data, sz) == CB_SUCCESS) {
+            ++global.cookie;
+        }
+    }
+}
+
 void free_params(struct param **pp) {
-    while (*pp) {
-        param *p = *pp;
-        free(p->name);
-        free(p->data);
-        *pp = p->next;
+    param *p = *pp;
+    if (p) {
+        cb_clear(&p->cb);
         free(p);
     }
+    *pp = 0;
 }
 
 const char *get_param(const struct param *p, const char *key)
 {
-    while (p != NULL) {
-        int cmp = strcmp(p->name, key);
-        if (cmp == 0) {
-            return p->data;
-        }
-        else if (cmp > 0) {
-            break;
-        }
-        p = p->next;
+    void *match;
+    if (p && cb_find_prefix(&p->cb, key, strlen(key)+1, &match, 1, 0) > 0) {
+        cb_get_kv_ex(match, &match);
+        return (const char *)match;
     }
     return NULL;
 }
@@ -1135,40 +1164,6 @@ double get_param_flt(const struct param *p, const char *key, double def)
     return str ? atof(str) : def;
 }
 
-void set_param(struct param **p, const char *key, const char *data)
-{
-    struct param *par;
-
-    ++global.cookie;
-    while (*p != NULL) {
-        int cmp = strcmp((*p)->name, key);
-        if (cmp == 0) {
-            par = *p;
-            free(par->data);
-            if (data) {
-                par->data = _strdup(data);
-            }
-            else {
-                *p = par->next;
-                free(par->name);
-                free(par);
-            }
-            return;
-        }
-        else if (cmp > 0) {
-            break;
-        }
-        p = &(*p)->next;
-    }
-    if (data) {
-        par = malloc(sizeof(param));
-        par->name = _strdup(key);
-        par->data = _strdup(data);
-        par->next = *p;
-        *p = par;
-    }
-}
-
 void kernel_done(void)
 {
     /* calling this function releases memory assigned to static variables, etc.
diff --git a/src/kernel/config.test.c b/src/kernel/config.test.c
index fab30fc6e..7078d17ac 100644
--- a/src/kernel/config.test.c
+++ b/src/kernel/config.test.c
@@ -130,6 +130,8 @@ static void test_get_set_param(CuTest * tc)
     set_param(&par, "bar", "foo");
     CuAssertStrEquals(tc, "bar", get_param(par, "foo"));
     CuAssertStrEquals(tc, "foo", get_param(par, "bar"));
+    set_param(&par, "bar", "bar");
+    CuAssertStrEquals(tc, "bar", get_param(par, "bar"));
     set_param(&par, "bar", NULL);
     CuAssertPtrEquals(tc, NULL, (void *)get_param(par, "bar"));
     free_params(&par);
@@ -175,11 +177,11 @@ static void test_forbiddenid(CuTest *tc) {
 CuSuite *get_config_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
-    SUITE_ADD_TEST(suite, test_forbiddenid);
-    SUITE_ADD_TEST(suite, test_getunit);
-    SUITE_ADD_TEST(suite, test_read_unitid);
     SUITE_ADD_TEST(suite, test_get_set_param);
     SUITE_ADD_TEST(suite, test_param_int);
     SUITE_ADD_TEST(suite, test_param_flt);
+    SUITE_ADD_TEST(suite, test_forbiddenid);
+    SUITE_ADD_TEST(suite, test_getunit);
+    SUITE_ADD_TEST(suite, test_read_unitid);
     return suite;
 }
diff --git a/src/util/rand.c b/src/util/rand.c
index 11f71839b..4e600b1a5 100644
--- a/src/util/rand.c
+++ b/src/util/rand.c
@@ -26,8 +26,6 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <float.h>
 #include <ctype.h>
 
-#define M_PIl   3.1415926535897932384626433832795029L   /* pi */
-
 /* NormalRand aus python, random.py geklaut, dort ist Referenz auf
 * den Algorithmus. mu = Mittelwert, sigma = Standardabweichung.
 * http://de.wikipedia.org/wiki/Standardabweichung#Diskrete_Gleichverteilung.2C_W.C3.BCrfel