diff --git a/src/Shell.c b/src/Shell.c
index 685b4726..9b543ec2 100755
--- a/src/Shell.c
+++ b/src/Shell.c
@@ -52,7 +52,7 @@ int Shell_ProcessInput(char *line)
     //trim string, for IRC etc. convenience
     for(int i=strlen(line)-1; i>=0; i--)
     {
-        if(!isspace(line[i]))
+        if(!isspace((int) line[i]))
         {
             break;
         }
diff --git a/src/unit_tests/HashTable_Test.h b/src/unit_tests/HashTable_Test.h
index 07e24c24..65dace26 100755
--- a/src/unit_tests/HashTable_Test.h
+++ b/src/unit_tests/HashTable_Test.h
@@ -22,21 +22,23 @@
  * THE SOFTWARE.
  */
 
+
+#define HASHTABLE_TEST_STRUCTURE_SIZE 10
 void HashTable_Test()
 {
     HashTable HTtest;
-    VMItem* HTest_storageptrs[CONCEPTS_MAX];
-    VMItem HTest_storage[CONCEPTS_MAX];
-    VMItem* HTest_HT[CONCEPTS_HASHTABLE_BUCKETS]; //the hash of the concept term is the index
+    VMItem* HTest_storageptrs[HASHTABLE_TEST_STRUCTURE_SIZE];
+    VMItem HTest_storage[HASHTABLE_TEST_STRUCTURE_SIZE];
+    VMItem* HTest_HT[HASHTABLE_TEST_STRUCTURE_SIZE]; //the hash of the concept term is the index
     puts(">>HashTable test start");
-    HashTable_INIT(&HTtest, HTest_storage, HTest_storageptrs, HTest_HT, CONCEPTS_HASHTABLE_BUCKETS, CONCEPTS_MAX, (Equal) Term_Equal, (Hash) Term_Hash);
-    assert(HTtest.VMStack.stackpointer == CONCEPTS_MAX, "The stack should be full!");
+    HashTable_INIT(&HTtest, HTest_storage, HTest_storageptrs, HTest_HT, HASHTABLE_TEST_STRUCTURE_SIZE, HASHTABLE_TEST_STRUCTURE_SIZE, (Equal) Term_Equal, (Hash) Term_Hash);
+    assert(HTtest.VMStack.stackpointer == HASHTABLE_TEST_STRUCTURE_SIZE, "The stack should be full!");
     //Insert a first concept:
     Term term1 = Narsese_Term("<a --> b>");
     Concept c1 = { .id = 1, .term = term1 };
     HashTable_Set(&HTtest, &term1, &c1);
-    assert(HTtest.VMStack.stackpointer == CONCEPTS_MAX-1, "One item should be taken off of the stack");
-    assert(HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS] != NULL, "Item didn't go in right place");
+    assert(HTtest.VMStack.stackpointer == HASHTABLE_TEST_STRUCTURE_SIZE-1, "One item should be taken off of the stack");
+    assert(HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE] != NULL, "Item didn't go in right place");
     //Return it
     Concept *c1_returned = HashTable_Get(&HTtest, &term1);
     assert(c1_returned != NULL, "Returned item is null (1)");
@@ -55,30 +57,30 @@ void HashTable_Test()
     Concept c3 = { .id = 3, .term = term3 }; //use different term but same hash, hash collision!
     HashTable_Set(&HTtest, &term3, &c3);
     //there should be a chain of 3 concepts now at the hash position:
-    assert(Term_Equal(HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS]->key, &c1.term), "c1 not there! (1)");
-    assert(Term_Equal(((VMItem*)HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS]->next)->key, &c2.term), "c2 not there! (1)");
-    assert(Term_Equal(((VMItem*)((VMItem*)HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS]->next)->next)->key, &c3.term), "c3 not there! (1)");
+    assert(Term_Equal(HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE]->key, &c1.term), "c1 not there! (1)");
+    assert(Term_Equal(((VMItem*)HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE]->next)->key, &c2.term), "c2 not there! (1)");
+    assert(Term_Equal(((VMItem*)((VMItem*)HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE]->next)->next)->key, &c3.term), "c3 not there! (1)");
     //Delete the middle one, c2
     HashTable_Delete(&HTtest, &term2);
-    assert(((Concept*)((VMItem*)HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS]->next)->value)->id == 3, "c3 not there according to id! (2)");
-    assert(Term_Equal(HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS]->key, &c1.term), "c1 not there! (2)");
-    assert(Term_Equal(((VMItem*)HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS]->next)->key, &c3.term), "c3 not there! (2)");
+    assert(((Concept*)((VMItem*)HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE]->next)->value)->id == 3, "c3 not there according to id! (2)");
+    assert(Term_Equal(HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE]->key, &c1.term), "c1 not there! (2)");
+    assert(Term_Equal(((VMItem*)HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE]->next)->key, &c3.term), "c3 not there! (2)");
     //Delete the last one, c3
     HashTable_Delete(&HTtest, &term3);
-    assert(Term_Equal(HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS]->key, &c1.term), "c1 not there! (3)");
+    assert(Term_Equal(HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE]->key, &c1.term), "c1 not there! (3)");
     //Delete the first one, which is the last one left, c1
     HashTable_Delete(&HTtest, &term1);
-    assert(HTtest.HT[c1.term.hash % CONCEPTS_HASHTABLE_BUCKETS] == NULL, "Hash table at hash position must be null");
-    assert(HTtest.VMStack.stackpointer == CONCEPTS_MAX, "All elements should be free now");
+    assert(HTtest.HT[c1.term.hash % HASHTABLE_TEST_STRUCTURE_SIZE] == NULL, "Hash table at hash position must be null");
+    assert(HTtest.VMStack.stackpointer == HASHTABLE_TEST_STRUCTURE_SIZE, "All elements should be free now");
     //test for chars:
     HashTable HTtest2;
-    VMItem* HTtest2_storageptrs[ATOMS_MAX];
-    VMItem HTtest2_storage[ATOMS_MAX];
-    VMItem* HTtest2_HT[ATOMS_HASHTABLE_BUCKETS];
-    HashTable_INIT(&HTtest2, HTtest2_storage, HTtest2_storageptrs, HTtest2_HT, ATOMS_HASHTABLE_BUCKETS, ATOMS_MAX, (Equal) Narsese_StringEqual, (Hash) Narsese_StringHash);
+    VMItem* HTtest2_storageptrs[HASHTABLE_TEST_STRUCTURE_SIZE];
+    VMItem HTtest2_storage[HASHTABLE_TEST_STRUCTURE_SIZE];
+    VMItem* HTtest2_HT[HASHTABLE_TEST_STRUCTURE_SIZE];
+    HashTable_INIT(&HTtest2, HTtest2_storage, HTtest2_storageptrs, HTtest2_HT, HASHTABLE_TEST_STRUCTURE_SIZE, HASHTABLE_TEST_STRUCTURE_SIZE, (Equal) Narsese_StringEqual, (Hash) Narsese_StringHash);
     char *testname = "test";
-    char blockname[ATOMIC_TERM_LEN_MAX] = {0};
-    strncpy(blockname, testname, ATOMIC_TERM_LEN_MAX-1);
+    char blockname[HASHTABLE_TEST_STRUCTURE_SIZE] = {0};
+    strncpy(blockname, testname, HASHTABLE_TEST_STRUCTURE_SIZE-1);
     HashTable_Set(&HTtest2, blockname, (void*) 42);
     long res = (long) HashTable_Get(&HTtest2, blockname);
     assert(res == 42, "Result is not right!");
diff --git a/src/unit_tests/Stack_Test.h b/src/unit_tests/Stack_Test.h
index be287123..5d33fcf4 100755
--- a/src/unit_tests/Stack_Test.h
+++ b/src/unit_tests/Stack_Test.h
@@ -22,12 +22,13 @@
  * THE SOFTWARE.
  */
 
+#define STACK_TEST_STRUCTURE_SIZE 5
 void Stack_Test()
 {
     puts(">>Stack test start");
     Stack stack = {0};
-    VMItem* storageptrs[CONCEPTS_MAX];
-    Stack_INIT(&stack, (void**) storageptrs, CONCEPTS_MAX);
+    VMItem* storageptrs[STACK_TEST_STRUCTURE_SIZE];
+    Stack_INIT(&stack, (void**) storageptrs, STACK_TEST_STRUCTURE_SIZE);
     Concept c1 = {0};
     Concept c2 = {0};
     VMItem item1 = { .value = &c1 };