diff --git a/tasksetgen.py b/tasksetgen.py
index 6686ae1..10d928c 100755
--- a/tasksetgen.py
+++ b/tasksetgen.py
@@ -3,7 +3,7 @@
 """
 Generates real time tasksets according to the method described in 'A Comparison
 of Global and Partitioned EDF Schedulability Tests for Multiprocessors'.
-Therefore tasks with random periods within the range 1 to 1000 are generated.
+Therefore tasks with random periods within the range 1 to 100 are generated.
 Depending on the mode, the utilization of these tasks is either determined by
 * uniform distribution between 1/period and 1
 * bimodal distribution heavy tasks with uniform distribution between 0.5 / 1 and
@@ -14,13 +14,47 @@ is 1/3
 """
 
 import datetime
+import shutil
 import sys
 import os
 import random
 import argparse
 import json
+import math
 from enum import Enum
 
+def query_yes_no(question, default=None):
+    """
+    Queries the user for a decision.
+    """
+
+    if default is None:
+        prompt = ' [y/n]'
+    elif default.lower() == 'yes':
+        prompt = ' [Y/n]'
+    elif default.lower() == 'no':
+        prompt = ' [y/N]'
+    else:
+        raise ValueError('Invalid default answer {}'.format(default))
+
+    while True:
+        print(question, prompt, end='')
+        choice = input().lower()
+        if 'yes'.find(choice) == 0:
+            return True
+        elif 'no'.find(choice) == 0:
+            return False
+
+def lcm(a, b):
+    return (a * b) / math.gcd(a, b)
+
+def hyperperiod(tasks):
+    periods = [x.period for task in tasks]
+    hyperperiod = periods[0]
+    for period in periods[1:]:
+        hyperperiod = lcm(hyperperiod, period)
+    return hyperperiod
+
 class Timebase(Enum):
     seconds = 1
     milliseconds = 2
@@ -59,7 +93,7 @@ def get_timebase_string(base):
         return 'std::chrono::nanoseconds', 'embb::base::DurationNanoseconds'
 
 def create_task(distribution):
-    period = random.uniform(1, 1000)
+    period = random.uniform(1, 30)
     if distribution is Distribution.uniform:
         util = random.uniform(1.0 / period, 1.0)
     elif distribution is Distribution.bimodal:
@@ -140,7 +174,8 @@ def main():
     while len(tasksets) < args.tasksetcount:
         taskset = []
         while len(taskset) < args.cores + 1 or \
-              check_taskset(args.cores, taskset) <= 1:
+              check_taskset(args.cores, taskset) <= 1 and \
+              hyperperiod(taskset) < 300000: # Limit hyperperiod to 5 minutes
             taskset.append(create_task(distribution))
             if len(taskset) >= args.cores + 1:
                 tasksets.append(taskset)
@@ -149,6 +184,14 @@ def main():
 
     cpp_base, embb_base = get_timebase_string(timebase)
 
+    try:
+        os.makedirs(args.target)
+    except FileExistsError:
+        if not query_yes_no('Folder exists, remove?', default='yes'):
+            sys.exit(1)
+    shutil.rmtree(args.target)
+    os.makedirs(args.target)
+
     print('Writing tasks…', file=sys.stderr)
     for taskset in tasksets:
         task_out = []