diff --git a/misc/script_proba.py b/misc/script_proba.py
new file mode 100644
index 0000000..469e65c
--- /dev/null
+++ b/misc/script_proba.py
@@ -0,0 +1,58 @@
+#!/usr/bin/python3
+
+"""
+Example of a script that uses SimSo.
+"""
+
+import sys
+from simso.core import Model
+from simso.configuration import Configuration
+
+
+def main(argv):
+    if len(argv) == 2:
+        # Configuration load from a file.
+        configuration = Configuration(argv[1])
+    else:
+        # Manual configuration:
+        configuration = Configuration()
+
+        configuration.cycles_per_ms = 1
+
+        configuration.etm = "pwcet"
+
+        configuration.duration = 100 * configuration.cycles_per_ms
+
+        # Add tasks:
+        configuration.add_task(name="T1", identifier=1,
+                               activation_date=0, pwcet=[(2, 0.5), (4, 0.5)], pmit=[(5, 0.2), (6, 0.8)], deadline=5, task_type="Probabilistic", abort_on_miss=True)
+
+        configuration.add_task(name="T2", identifier=2,
+                               activation_date=0, pwcet=[(3, 0.5), (4, 0.5)], pmit=[(7, 0.5), (8, 0.5)], deadline=7, task_type="Probabilistic", abort_on_miss=True)
+
+        configuration.add_task(name="T3", identifier=3,
+                               activation_date=0, pwcet=[(3, 0.5), (4, 0.5)], pmit=[(8, 0.5), (9, 0.5)], deadline=8, task_type="Probabilistic", abort_on_miss=True)
+
+        # Add a processor:
+        configuration.add_processor(name="CPU 1", identifier=1)
+        # configuration.add_processor(name="CPU 2", identifier=2)
+
+        # Add a scheduler:
+        # configuration.scheduler_info.filename = "./simso/schedulers/RM.py"
+        configuration.scheduler_info.clas = "simso.schedulers.RM"
+
+    # Check the config before trying to run it.
+    configuration.check_all()
+
+    # Init a model from the configuration.
+    model = Model(configuration)
+
+    # Execute the simulation.
+    model.run_model()
+
+    # Print logs.
+    for log in model.logs:
+        print(log)
+
+
+main(sys.argv)
diff --git a/script.py b/script.py
index 4ae9b1f..bbf1879 100755
--- a/script.py
+++ b/script.py
@@ -6,6 +6,7 @@ Example of a script that uses SimSo.
 
 import sys
 from simso.core import Model
+from simso.core.Fault import ProcessorFailure, VoltageDrop, PriorityInversion, TimingError
 from simso.configuration import Configuration
 
 
@@ -22,22 +23,24 @@ def main(argv):
         configuration.duration = 100 * configuration.cycles_per_ms
 
         # Add tasks:
-        configuration.add_task(name="T1", identifier=1, period=7,
-                               activation_date=0, wcet=3, deadline=7)
+        configuration.add_task(name="T1", identifier=1, period=8,
+                               activation_date=0, wcet=4, deadline=7)
         configuration.add_task(name="T2", identifier=2, period=12,
                                activation_date=0, wcet=3, deadline=8)
-        configuration.add_task(name="T4", identifier=4, period=15,
+        configuration.add_task(name="T3", identifier=3, period=15,
                                activation_date=0, wcet=5, deadline=14)
-        configuration.add_task(name="T3", identifier=3, period=20,
-                               activation_date=0, wcet=5, deadline=9)
+        task = configuration.add_task(name="T4", identifier=4, period=20,
+                                      activation_date=0, wcet=6, deadline=12)
 
         # Add a processor:
-    configuration.add_processor(name="CPU 1", identifier=1, cs_overhead=1)
-    configuration.add_processor(name="CPU 2", identifier=2, cs_overhead=1)
+    configuration.add_processor(name="CPU 1", identifier=1)
+    proc = configuration.add_processor(name="CPU 2", identifier=2)
+
+    configuration.add_fault(TimingError(task, "period", 8), 0, 21)
 
     # Add a scheduler:
     #configuration.scheduler_info.filename = "../simso/schedulers/RM.py"
-    configuration.scheduler_info.clas = "simso.schedulers.RM"
+    configuration.scheduler_info.clas = "simso.schedulers.EDF"
 
     # Check the config before trying to run it.
     configuration.check_all()
diff --git a/script_proba.py b/script_proba.py
index 4d26e25..3e27609 100644
--- a/script_proba.py
+++ b/script_proba.py
@@ -35,7 +35,7 @@ def main(argv):
 
         # Add a processor:
         configuration.add_processor(name="CPU 1", identifier=1)
-        configuration.add_processor(name="CPU 2", identifier=2)
+        # configuration.add_processor(name="CPU 2", identifier=2)
 
         # Add a scheduler:
         configuration.scheduler_info.filename = "./simso/schedulers/RM.py"
diff --git a/simso/configuration/Configuration.py b/simso/configuration/Configuration.py
index 539911e..5dc3cd6 100644
--- a/simso/configuration/Configuration.py
+++ b/simso/configuration/Configuration.py
@@ -4,10 +4,12 @@
 import os
 import re
 from xml.dom import minidom
+from functools import reduce
 from simso.core.Scheduler import SchedulerInfo
 from simso.core import Scheduler
 from simso.core.Task import TaskInfo
 from simso.core.Processor import ProcInfo
+from simso.core.Fault import FaultInfo, FaultFunction
 from simso.generator.task_generator import gen_probabilistic_arrivals
 from simso.generator.task_generator import cdf
 
@@ -22,7 +24,7 @@ if not hasattr(minidom.NamedNodeMap, '__contains__'):
 
 def _gcd(*numbers):
     """Return the greatest common divisor of the given integers"""
-    from fractions import gcd
+    from math import gcd
     return reduce(gcd, numbers)
 
 
@@ -60,6 +62,7 @@ class Configuration(object):
             self._scheduler_info = parser.scheduler_info
             self.penalty_preemption = parser.penalty_preemption
             self.penalty_migration = parser.penalty_migration
+            self.fault_info_list = parser.fault_info_list
         else:
             self.etm = "wcet"
             self.duration = 100000000
@@ -71,6 +74,7 @@ class Configuration(object):
             self.task_data_fields = {}
             self._proc_info_list = []
             self.proc_data_fields = {}
+            self.fault_info_list = []
             self.memory_access_time = 100
             self._scheduler_info = SchedulerInfo()
         self.calc_penalty_cache()
@@ -315,3 +319,10 @@ class Configuration(object):
             speed)
         self.proc_info_list.append(proc)
         return proc
+
+    def add_fault(self, fault_function, start_time, end_time):
+        """
+        Helper method to create a FaultInfo and add it to the list of faults.
+        """
+        fault = FaultInfo(start_time, end_time, fault_function)
+        self.fault_info_list.append(fault)
diff --git a/simso/configuration/parser.py b/simso/configuration/parser.py
index d64e0b3..f2b79cd 100644
--- a/simso/configuration/parser.py
+++ b/simso/configuration/parser.py
@@ -20,6 +20,7 @@ class Parser(object):
     """
     Simulation file parser.
     """
+
     def __init__(self, filename):
         self.filename = filename
         self.cur_dir = os.path.split(filename)[0]
@@ -34,6 +35,11 @@ class Parser(object):
         self._parse_processors()
         self._parse_scheduler()
         self._parse_penalty()
+        self._parse_faults()
+
+    def _parse_faults(self):
+        # TODO: implement parser for faults
+        self.fault_info_list = []
 
     def _parse_caches(self):
         self.caches_list = []
@@ -90,29 +96,31 @@ class Parser(object):
                     map(float, attr['list_activation_dates'].value.split(',')))
 
             t = TaskInfo(
-                attr['name'].value,
-                int(attr['id'].value),
-                task_type,
-                'abort_on_miss' not in attr
+                name=attr['name'].value,
+                identifier=int(attr['id'].value),
+                task_type=task_type,
+                abort_on_miss='abort_on_miss' not in attr
                 or attr['abort_on_miss'].value == 'yes',
-                float(attr['period'].value),
-                float(attr['activationDate'].value)
+                period=float(attr['period'].value),
+                activation_date=float(attr['activationDate'].value)
                 if 'activationDate' in attr else 0,
-                int(attr['instructions'].value),
-                float(attr['mix'].value),
-                (self.cur_dir + '/' + attr['stack'].value,
-                    self.cur_dir) if 'stack' in attr else ("", self.cur_dir),
-                float(attr['WCET'].value),
-                float(attr['ACET'].value) if 'ACET' in attr else 0,
-                float(attr['et_stddev'].value) if 'et_stddev' in attr else 0,
-                float(attr['deadline'].value),
-                float(attr['base_cpi'].value),
-                int(attr['followed_by'].value)
+                n_instr=int(attr['instructions'].value),
+                mix=float(attr['mix'].value),
+                stack_file=(self.cur_dir + '/' + attr['stack'].value,
+                            self.cur_dir) if 'stack' in attr else ("", self.cur_dir),
+                wcet=float(attr['WCET'].value),
+                acet=float(attr['ACET'].value) if 'ACET' in attr else 0,
+                pwcet=float(attr['PWCET'].value) if 'PWCET' in attr else 0,
+                et_stddev=float(
+                    attr['et_stddev'].value) if 'et_stddev' in attr else 0,
+                deadline=float(attr['deadline'].value),
+                base_cpi=float(attr['base_cpi'].value),
+                followed_by=int(attr['followed_by'].value)
                 if 'followed_by' in attr else None,
-                list_activation_dates,
-                int(float(attr['preemption_cost'].value))
+                list_activation_dates=list_activation_dates,
+                preemption_cost=int(float(attr['preemption_cost'].value))
                 if 'preemption_cost' in attr else 0,
-                data)
+                data=data)
             self.task_info_list.append(t)
 
     def _parse_processors(self):
@@ -244,5 +252,5 @@ class Parser(object):
             clas=clas, overhead=overhead, overhead_activate=overhead_activate,
             overhead_terminate=overhead_terminate, fields=data)
         if filename and filename[0] != '/':
-                filename = self.cur_dir + '/' + filename
+            filename = self.cur_dir + '/' + filename
         self.scheduler_info.filename = filename
diff --git a/simso/core/Fault.py b/simso/core/Fault.py
new file mode 100644
index 0000000..5ab60a9
--- /dev/null
+++ b/simso/core/Fault.py
@@ -0,0 +1,160 @@
+from simpy import Environment
+from typing import Callable
+from simso.core.Processor import ProcInfo
+
+
+class FaultFunction:
+    """
+    The FaultFunction class changes the actual behaviour of the faulty element.
+    """
+
+    def __init__(self, start_function: Callable, end_function: Callable):
+        self.start_function = start_function
+        self.end_function = end_function
+
+
+class FaultInfo:
+    """
+    The FaultType class is responsible for causing the error.
+    """
+
+    def __init__(self, start_time: float, end_time: float, fault_function: FaultFunction):
+        self.start_time = start_time
+        self.end_time = end_time
+        self.fault_function = fault_function
+
+
+class Fault:
+    """
+    The Fault class is the simpy process for triggering a certain error.
+    """
+
+    def __init__(self, sim, fault_type: FaultInfo):
+        self._fault_type = fault_type
+        self._sim = sim
+        self.process = self._sim.process(self.release())
+
+    def release(self):
+        yield self._sim.timeout(self._fault_type.start_time)
+
+        self._fault_type.fault_function.start_function(self._sim)
+
+        yield self._sim.timeout(self._fault_type.end_time -
+                                self._fault_type.start_time)
+
+        self._fault_type.fault_function.end_function(self._sim)
+
+
+class ProcessorFailure(FaultFunction):
+    """
+    The ProcessorFailure class simulates a complete stoppage of a processor.
+    """
+
+    def __init__(self, proc_info: ProcInfo):
+        super().__init__(self.stop_processor, self.start_processor)
+        self._proc_info = proc_info
+        self._processor = None
+
+    def stop_processor(self, model):
+        self._processor = next(
+            p for p in model.processors if p.identifier == self._proc_info.identifier)
+        self._processor.fail(self)
+
+    def start_processor(self, model):
+        self._processor.fail()
+
+
+class VoltageChange(FaultFunction):
+
+    def __init__(self, proc_info_list, scaling: float):
+        super().__init__(self.start_voltage_change, self.end_voltage_change)
+        self._proc_info_list = proc_info_list
+        self._processor_list = []
+        self._scaling = scaling
+
+    def start_voltage_change(self, model):
+        affected_ids = [p.identifier for p in self._proc_info_list]
+        self._processor_list = [
+            p for p in model.processors if p.identifier in affected_ids]
+        for p in self._processor_list:
+            p.set_speed(self._scaling * p.speed)
+
+    def end_voltage_change(self, model):
+        for p in self._processor_list:
+            speed = next(
+                pi for pi in self._proc_info_list if pi.identifier == p.identifier).speed
+            p.set_speed(speed)
+
+
+class VoltageDrop(VoltageChange):
+    """
+    The VoltageDrop class simulates the slowdown of one or more processors due to voltage drops.
+    """
+
+    def __init__(self, proc_info_list, scaling: float):
+        assert scaling >= 0 and scaling <= 1.0, "Voltage drop reduces the speed of a processor, i.e. scaling has to be >= 0 and <= 1"
+        super().__init__(proc_info_list, scaling)
+
+
+# TODO: rethink this class
+class PriorityInversion(FaultFunction):
+    """
+    The PriorityInversion class simulates changes in the priority of a job.
+    """
+
+    def __init__(self, proc_info, until_sched: bool = False):
+        """
+        lambd: Expects task and new value as parameter and returns old value
+        """
+        super().__init__(self.start_priority_inversion, self.end_priority_inversion)
+        self._proc_info = proc_info
+        self._until_sched = until_sched
+
+    def start_priority_inversion(self, model):
+        proc = next(p for p in model.processors if p.identifier ==
+                    self._proc_info.identifier)
+        sched = model.scheduler
+        running_jobs = [
+            p.running for p in model.processors if p.running is not None]
+        job = next(t.job for t in sched.task_list if t.job.is_active()
+                   and t.job not in running_jobs)
+
+        if job is not None:
+            pass
+
+    def end_priority_inversion(self, model):
+        pass
+
+
+class TimingChange(FaultFunction):
+    """
+    The TimingError class simulates changes in the timing parameters, e.g. deadline, period etc.
+    """
+
+    def __init__(self, task_info, parameter: str, value: float):
+        super().__init__(self.start_timing_change, self.end_timing_change)
+        self._task_info = task_info
+        self._parameter = parameter
+        self._value = value
+        self._old_value = getattr(self._task_info, parameter)
+
+    def start_timing_change(self, model):
+        setattr(self._task_info, self._parameter, self._value)
+
+    def end_timing_change(self, model):
+        setattr(self._task_info, self._parameter, self._old_value)
+
+
+class TimingError(TimingChange):
+    """
+    The TimingError class simulates changes in the timing parameters, e.g. deadline, period etc.
+    """
+
+    def __init__(self, task_info, parameter: str, value: float):
+        super().__init__(task_info, parameter, value)
+
+
+class Redundancy(TimingChange):
+
+    def __init__(self, task_info, value: float):
+        super().__init__(task_info, "wcet", task_info.wcet + value)
diff --git a/simso/core/Job.py b/simso/core/Job.py
index b0d4aec..52c163c 100644
--- a/simso/core/Job.py
+++ b/simso/core/Job.py
@@ -94,6 +94,7 @@ class Job:
         self._sim.logger.log(self.name + " Preempted! ret: " +
                              str(self.ret), kernel=True)  # TODO: what to pass as interrupted?
 
+    # TODO: Jobs that terminate after their deadline are not recorded
     def _on_terminated(self):
         self._on_stop_exec()
         self._etm.on_terminated(self)
@@ -322,11 +323,3 @@ class Job:
                 if ret <= 0:
                     # End of job.
                     self._on_terminated()
-
-
-class SequentialJob(Job):
-    pass
-
-
-class ParallelJob(Job):
-    pass
diff --git a/simso/core/Model.py b/simso/core/Model.py
index 3a3bc7a..e1ba7e4 100644
--- a/simso/core/Model.py
+++ b/simso/core/Model.py
@@ -8,6 +8,7 @@ from simso.core.Timer import Timer
 from simso.core.etm import execution_time_models
 from simso.core.Logger import Logger
 from simso.core.results import Results
+from simso.core.Fault import Fault
 
 
 class Model(Environment):
@@ -31,6 +32,7 @@ class Model(Environment):
         self._logger = Logger(self)
         task_info_list = configuration.task_info_list
         proc_info_list = configuration.proc_info_list
+        fault_info_list = configuration.fault_info_list
         self._cycles_per_ms = configuration.cycles_per_ms
         self.scheduler = configuration.scheduler_info.instantiate(self)
 
@@ -59,6 +61,10 @@ class Model(Environment):
             proc.caches = proc_info.caches
             self._processors.append(proc)
 
+        self._fault_list = []
+        for fault_info in fault_info_list:
+            self._fault_list.append(Fault(self, fault_info))
+
         # XXX: too specific.
         self.penalty_preemption = configuration.penalty_preemption
         self.penalty_migration = configuration.penalty_migration
diff --git a/simso/core/Processor.py b/simso/core/Processor.py
index 7ff4e0d..c1ebcb4 100644
--- a/simso/core/Processor.py
+++ b/simso/core/Processor.py
@@ -14,6 +14,7 @@ TERMINATE = 3
 TIMER = 4
 PREEMPT = 5
 SPEED = 6
+FAIL = 7
 
 
 class ProcInfo(object):
@@ -75,6 +76,7 @@ class Processor:
             env=model, name="Monitor Timer" + proc_info.name)
         self._speed = proc_info.speed
         self.process = self._model.process(self.run())
+        self._fault = None
 
     def resched(self):
         """
@@ -91,11 +93,14 @@ class Processor:
             self._running = None
 
     def preempt(self, job=None):
-        # self._evts = deque([e for e in self._evts if e[0] != PREEMPT])
         self._evts.clear_events(PREEMPT)
         self._evts.append((PREEMPT,))
         self._running = job
 
+    def fail(self, fault=None):
+        self._evts.append((FAIL, fault))
+        self._fault = fault  # TODO: check if I need this
+
     def timer(self, timer):
         self._evts.append((TIMER, timer))
 
@@ -202,6 +207,13 @@ class Processor:
                 evt[1].call_handler()
             elif evt[0] == SPEED:
                 self._speed = evt[1]
+            elif evt[0] == FAIL:
+                if self._fault is not None:
+                    self.sched.processors.remove(self)
+                elif not self in self.sched.processors:
+                    self.sched.processors.append(self)
+
+                self.resched()  # TODO: changed from preempt, check if still works
             elif evt[0] == RESCHED:
                 self.monitor.observe(ProcOverheadEvent("Scheduling"))
                 self.sched.monitor_begin_schedule(self)
diff --git a/simso/core/Scheduler.py b/simso/core/Scheduler.py
index 884c7bb..76e9963 100644
--- a/simso/core/Scheduler.py
+++ b/simso/core/Scheduler.py
@@ -14,12 +14,12 @@ from simso.core.SchedulerEvent import SchedulerBeginScheduleEvent, \
     SchedulerEndTerminateEvent
 
 
-
 class SchedulerInfo(object):
     """
     SchedulerInfo groups the data that characterize a Scheduler (such as the
     scheduling overhead) and do the dynamic loading of the scheduler.
     """
+
     def __init__(self, clas='', overhead=0, overhead_activate=0,
                  overhead_terminate=0, fields=None):
         """
@@ -142,7 +142,7 @@ class Scheduler(object):
         self.sim = sim
         self.processors = []
         self.task_list = []
-        self._lock = Resource(sim) 
+        self._lock = Resource(sim)
         self.overhead = scheduler_info.overhead
         self.overhead_activate = scheduler_info.overhead_activate
         self.overhead_terminate = scheduler_info.overhead_terminate
@@ -220,7 +220,7 @@ class Scheduler(object):
         """
         Release the lock. Goes in pair with :meth:`get_lock`.
         """
-        self._lock.release(request) 
+        self._lock.release(request)
 
     def monitor_begin_schedule(self, cpu):
         self.monitor.observe(SchedulerBeginScheduleEvent(cpu))
diff --git a/simso/core/Timer.py b/simso/core/Timer.py
index 0a4011b..982269b 100644
--- a/simso/core/Timer.py
+++ b/simso/core/Timer.py
@@ -16,7 +16,6 @@ class InstanceTimer:
         self.cpu = timer.cpu
         self.running = False
         self.overhead = timer.overhead
-        self.process = self._sim.process(self.run())
 
     def call_handler(self):
         if self.running:
diff --git a/simso/core/etm/WCET.py b/simso/core/etm/WCET.py
index 7848171..7213bd0 100644
--- a/simso/core/etm/WCET.py
+++ b/simso/core/etm/WCET.py
@@ -42,6 +42,7 @@ class WCET(AbstractExecutionTimeModel):
 
     def get_ret(self, job):
         wcet_cycles = int(job.wcet * self.sim.cycles_per_ms)
+        # TODO: this leads to rounding errors, use ceil?
         return int(wcet_cycles - self.get_executed(job))
 
     def update(self):
diff --git a/simso/core/results.py b/simso/core/results.py
index 60340b3..27edf25 100644
--- a/simso/core/results.py
+++ b/simso/core/results.py
@@ -8,6 +8,7 @@ class ProcessorR(object):
     Add information about a processor such as the number of CxtSave and
     CxtLoad and their total overhead.
     """
+
     def __init__(self):
         self.context_save_overhead = 0
         self.context_save_count = 0
@@ -20,6 +21,7 @@ class SchedulerR(object):
     Add information about the scheduler such as the number of scheduling
     events and their total overhead.
     """
+
     def __init__(self):
         self.schedule_overhead = 0
         self.activate_overhead = 0
@@ -36,6 +38,7 @@ class TaskR(object):
 
     The attribute jobs contains a list of JobR, sorted by activation date.
     """
+
     def __init__(self, task, delta_preemption=100):
         self.task = task
         self.delta_preemption = delta_preemption
@@ -144,6 +147,7 @@ class JobR(object):
     Add a set of metrics to a job. Such metrics include: preemption count,
     migration count, response time, etc.
     """
+
     def __init__(self, date, job):
         self.job = job
         self.preemption_count = 0
@@ -206,6 +210,7 @@ class Results(object):
 
     .
     """
+
     def __init__(self, model):
         self.model = model
         self.error = None
@@ -235,7 +240,7 @@ class Results(object):
             for task in self.model.task_list:
                 if indices[task] < len(monitors[task]):
                     evt = monitors[task][indices[task]]
-                    if m is None or evt[1].id_ < m[0][1].id_:
+                    if m is None or evt[1].id_ < m[0][1].id_:  # pylint: disable=E1136
                         m = (evt, task)
             if m is None:
                 break
diff --git a/simso/schedulers/EDF.py b/simso/schedulers/EDF.py
index 422f108..4f32388 100644
--- a/simso/schedulers/EDF.py
+++ b/simso/schedulers/EDF.py
@@ -5,9 +5,11 @@ architectures.
 from simso.core import Scheduler
 from simso.schedulers import scheduler
 
+
 @scheduler("simso.schedulers.EDF")
 class EDF(Scheduler):
     """Earliest Deadline First"""
+
     def on_activate(self, job):
         job.cpu.resched()
 
@@ -22,7 +24,7 @@ class EDF(Scheduler):
         if ready_jobs:
             # Select a free processor or, if none,
             # the one with the greatest deadline (self in case of equality):
-            key = lambda x: (
+            def key(x): return (
                 1 if not x.running else 0,
                 x.running.absolute_deadline if x.running else 0,
                 1 if x is cpu else 0
@@ -34,5 +36,5 @@ class EDF(Scheduler):
 
             if (cpu_min.running is None or
                     cpu_min.running.absolute_deadline > job.absolute_deadline):
-                print(self.sim.now, job.name, cpu_min.name)
+                # print(self.sim.now, job.name, cpu_min.name)
                 return (job, cpu_min)