diff --git a/.clang-tidy b/.clang-tidy
index f404c2e..11c1ab7 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -1,3 +1,3 @@
-Checks: '*,-llvm-header-guard,-fuchsia*,-cppcoreguidelines-pro-bounds-pointer-arithmetic,-cppcoreguidelines-pro-bounds-constant-array-index,-bugprone-narrowing-conversions,-cppcoreguidelines-narrowing-conversions,-cppcoreguidelines-pro-type-const-cast,-cppcoreguidelines-pro-type-reinterpret-cast,-hicpp-signed-bitwise,-bugprone-exception-escape,-cppcoreguidelines-pro-type-member-init,-cppcoreguidelines-pro-type-cstyle-cast,-hicpp-member-init,-google-readability-namespace-comments,-llvm-namespace-comment,-cppcoreguidelines-pro-type-vararg,-hicpp-vararg,-modernize-use-trailing-return-type'
+Checks: '*,-llvm-header-guard,-fuchsia*,-cppcoreguidelines-pro-bounds-pointer-arithmetic,-cppcoreguidelines-pro-bounds-constant-array-index,-bugprone-narrowing-conversions,-cppcoreguidelines-narrowing-conversions,-cppcoreguidelines-pro-type-const-cast,-cppcoreguidelines-pro-type-reinterpret-cast,-hicpp-signed-bitwise,-bugprone-exception-escape,-cppcoreguidelines-pro-type-member-init,-cppcoreguidelines-pro-type-cstyle-cast,-hicpp-member-init,-google-readability-namespace-comments,-llvm-namespace-comment,-cppcoreguidelines-pro-type-vararg,-hicpp-vararg,-modernize-use-trailing-return-type,-readability-magic-numbers,-cppcoreguidelines-avoid-magic-numbers'
 WarningsAsErrors: 'true'
 HeaderFilterRegex: '.*,-catch.hpp'
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1554107..1e7c069 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,4 +39,13 @@ target_link_libraries(UnitTests Catch2::Catch2)
 
 include(CTest)
 include(Catch)
-catch_discover_tests(UnitTests)
\ No newline at end of file
+catch_discover_tests(UnitTests)
+
+if (ENABLE_COVERAGE)
+    set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/../external/codecov/cmake" ${CMAKE_MODULE_PATH})
+    list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/CMake")
+    find_package(codecov)
+    add_coverage(UnitTests)
+    list(APPEND LCOV_REMOVE_PATTERNS "/usr/")
+    coverage_evaluate()
+endif()
diff --git a/src/Color.cpp b/src/Color.cpp
index 8f03829..8b9629d 100644
--- a/src/Color.cpp
+++ b/src/Color.cpp
@@ -2,16 +2,21 @@
 
 namespace vkvm {
 
+    constexpr int maxValue = 255;
+
     Color::Color() noexcept
             : red(0), green(0), blue(0) {}
 
-    Color::Color(unsigned char red, unsigned char green, unsigned char blue) noexcept
-            : red(red), green(green), blue(blue) {}
+    Color::Color(int red, int green, int blue) noexcept {
+        setRed(red);
+        setGreen(green);
+        setBlue(blue);
+    }
 
     Color::Color(unsigned int hex) noexcept {
-        red = (unsigned char) ((hex >> 16 & 0xFF));//NOLINT
-        green = (unsigned char) ((hex >> 8u & 0xFF));//NOLINT
-        blue = (unsigned char) ((hex & 0xFF));//NOLINT
+        red = static_cast<unsigned char>(hex >> 16 & 0xFF);
+        green = static_cast<unsigned char>(hex >> 8U & 0xFF);
+        blue = static_cast<unsigned char>((hex & 0xFF));
     }
 
     auto Color::getRed() -> unsigned char {
@@ -26,15 +31,27 @@ namespace vkvm {
         return blue;
     }
 
-    auto Color::setRed(unsigned char value) -> void {
+    auto Color::setRed(int value) -> void {
+        if(value > maxValue) {
+            value = maxValue;
+        }
+
         red = value;
     }
 
-    auto Color::setGreen(unsigned char value) -> void {
+    auto Color::setGreen(int value) -> void {
+        if(value > maxValue) {
+            value = maxValue;
+        }
+
         green = value;
     }
 
-    auto Color::setBlue(unsigned char value) -> void {
+    auto Color::setBlue(int value) -> void {
+        if(value > maxValue) {
+            value = maxValue;
+        }
+
         blue = value;
     }
 
diff --git a/src/Color.hpp b/src/Color.hpp
index 8b3cc99..29c379e 100644
--- a/src/Color.hpp
+++ b/src/Color.hpp
@@ -18,7 +18,7 @@ namespace vkvm {
     public:
         Color() noexcept;
 
-        Color(unsigned char red, unsigned char green, unsigned char blue) noexcept;
+        Color(int red, int green, int blue) noexcept;
 
         explicit Color(unsigned int hex) noexcept;
 
@@ -28,11 +28,11 @@ namespace vkvm {
 
         auto getBlue() -> unsigned char;
 
-        auto setRed(unsigned char value) -> void;
+        auto setRed(int value) -> void;
 
-        auto setGreen(unsigned char value) -> void;
+        auto setGreen(int value) -> void;
 
-        auto setBlue(unsigned char value) -> void;
+        auto setBlue(int value) -> void;
 
         bool operator==(const Color &other) const ;
 
diff --git a/src/FontType.cpp b/src/FontType.cpp
deleted file mode 100644
index 5e69054..0000000
--- a/src/FontType.cpp
+++ /dev/null
@@ -1,24 +0,0 @@
-#include "FontType.hpp"
-
-namespace vkvm {
-
-    FontType::FontType(int id, const char * name, int height, int width) noexcept : id(id), name(name), height(height), width(width) {
-    }
-
-    auto FontType::getId() const -> int {
-        return id;
-    }
-
-    auto FontType::getName() const -> std::string {
-        return std::string(name);
-    }
-
-    auto FontType::getHeight() const -> int {
-        return height;
-    }
-
-    auto FontType::getWidth() const -> int {
-        return width;
-    }
-
-}
\ No newline at end of file
diff --git a/src/FontType.hpp b/src/FontType.hpp
index 349abd1..cff32e1 100644
--- a/src/FontType.hpp
+++ b/src/FontType.hpp
@@ -2,32 +2,15 @@
 
 #define LIBRARY_FONT_H
 
-#include <string>
-#include <utility>
-
 namespace vkvm {
 
-    class FontType {
-    private:
-        int id;
-        const char * name;
-        int height;
-        int width;
-
-    public:
-        FontType(int id, const char * name, int height, int width) noexcept;
-
-        auto getId() const -> int;
-
-        auto getName() const -> std::string;
-
-        auto getHeight() const -> int;
-
-        auto getWidth() const -> int;
-
+    enum FontType {
+        FuturisticBlack = 1,
+        //TODO(julian): find name of this font
+        NoNameFound = 2,
+        ProFontIIX = 3,
+        Unifont = 4
     };
-
-    static const FontType font_1 = FontType(1, "DummyFont", 10, 5);
 }
 
 #endif
diff --git a/src/KeyCode.hpp b/src/KeyCode.hpp
index d09dfdb..c618e7c 100644
--- a/src/KeyCode.hpp
+++ b/src/KeyCode.hpp
@@ -1,14 +1,17 @@
 #ifndef LIBRARY_KEYCODE_HPP
 #define LIBRARY_KEYCODE_HPP
 
-#include <sys/types.h>
 
 namespace vkvm {
 
     enum KeyCode {
-        Backspcce = 32,
+        Backspace = 32,
         Tab = 33,
         Enter = 37,
+        Arrow_Left = 105,
+        Arrow_Down = 108,
+        Arrow_Right = 107,
+        Arrow_Up = 106,
         ShiftLeft = 249,
         ShiftRight = 249,
         Ctrl = 251,
diff --git a/src/SharedMemoryAccess.cpp b/src/SharedMemoryAccess.cpp
index 57392e3..d129346 100644
--- a/src/SharedMemoryAccess.cpp
+++ b/src/SharedMemoryAccess.cpp
@@ -1,30 +1,24 @@
 #include <cstdio>
-#include <cstdlib>
 #include <cstring>
-#include <iostream>
 #include <sys/ipc.h>
 #include <sys/sem.h>
 #include <sys/shm.h>
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <unistd.h>
 
-#include "SharedMemoryAccess.hpp"  /* header is important for the shmID. name could be different. maybe not needed cause: (shmget(memory_access_key, NULL, 0)) */
+#include "SharedMemoryAccess.hpp"
 #include "internal.hpp"
 #include "log.hpp"
 
 namespace vkvm {
-    constexpr int PERM = 0666;      /* access rights */
+    constexpr int PERMISSION = 0666;
     constexpr int LOCK = -1;
     constexpr int UNLOCK = 1;
     constexpr int SEM_KEY = 123458L;
 
-//int memoryAccessKey; /* var type is int. but could be another type. */ //TODO: look after type in sharedmemory group
     int semId;
     struct sembuf semaphore;
 
-    std::vector<char> localSharedMemory;
-
     auto initSemaphore() -> int {
         /* Testen, ob das Semaphor bereits existiert */
         semId = semget(SEM_KEY, 0, IPC_PRIVATE);
@@ -33,7 +27,7 @@ namespace vkvm {
             /* Alle Zugriffsrechte der Dateikreierungsmaske */
             /* erlauben                                     */
             umask(0);
-            semId = semget(SEM_KEY, 1, IPC_CREAT | IPC_EXCL | PERM);
+            semId = semget(SEM_KEY, 1, IPC_CREAT | IPC_EXCL | PERMISSION);
             if (semId < 0) {
                 return -1;
             }
@@ -50,6 +44,7 @@ namespace vkvm {
         semaphore.sem_flg = SEM_UNDO;
         if (semop(semId, &semaphore, 1) == -1) {
             perror(" semop ");
+            log(LogLevel::CRITICAL, "could not operate on semaphore, exiting");
             return -1;
         }
         return 1;
@@ -67,11 +62,11 @@ namespace vkvm {
             givenWarning = true;
             log(LogLevel::WARNING, "no shared memory found, using local memory instead!");
         }
-        if (localSharedMemory.empty()) {
+        if (impl.localSharedMemory.empty()) {
             constexpr int kilo = 1024;
-            localSharedMemory.resize(impl.sharedMemorySize * kilo);
+            impl.localSharedMemory.resize(impl.sharedMemorySize * kilo);
         }
-        return &localSharedMemory[0];
+        return &impl.localSharedMemory[0];
     }
 
     auto getSharedMemory() -> char * {
@@ -90,6 +85,7 @@ namespace vkvm {
             impl.sharedMemory = ptr;
             return ptr;
         }
+        //using a local buffer for shared memory testing
         return getLocalMemory();
     }
 
diff --git a/src/internal.cpp b/src/internal.cpp
index 436c76e..a889c4a 100644
--- a/src/internal.cpp
+++ b/src/internal.cpp
@@ -8,6 +8,26 @@ namespace vkvm {
 
     Impl impl;
 
+    auto setDefaultValues() -> void {
+        impl.localMemoryWarn = false;
+        if (getSharedMemory() != nullptr) {
+            if(getSharedMemory() == &impl.localSharedMemory[0]) {
+                setMode(GraphicMode::RGB);
+                setCharactersPerRow(60);
+                setCharactersPerColumn(20);
+                setHeight(600);
+                setWidth(800);
+                setMousePosition(42, 42);
+                setBackgroundColor(black);
+                setForegroundColor(white);
+                setRedrawInterval(500);
+                setTimerInterruptInterval(1000);
+                setFont(FontType::ProFontIIX);
+            }
+        }
+        impl.localMemoryWarn = true;
+    }
+
     auto sendSignal(pid_t pid, int signalNumber) -> void {
         kill(pid, signalNumber);
     }
@@ -50,18 +70,21 @@ namespace vkvm {
         lockSharedMemory();
         getRegisters()->layout_version = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto setCharactersPerColumn(int newValue) -> void {
         lockSharedMemory();
         getRegisters()->characters_per_column = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto setCharactersPerRow(int newValue) -> void {
         lockSharedMemory();
         getRegisters()->characters_per_row = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto setMousePosition(int x, int y) -> void {
@@ -69,16 +92,26 @@ namespace vkvm {
         getRegisters()->mouse_pos_x = x;
         getRegisters()->mouse_pos_y = y;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto buttonPressed(KeyCode keyCode) -> void {
         lockSharedMemory();
         auto reg = getRegisters();
-        if (reg->keyboardBuffer_index_write >= sizeof(reg->keyboardBuffer)) {
-            reg->keyboardBuffer_index_write = 0;
-        }
-        reg->keyboardBuffer[reg->keyboardBuffer_index_write++] = keyCode;
+        reg->keyboardBuffer[(reg->keyboardBuffer_index_write) % keyboardBufferSize] = keyCode;
         unlockSharedMemory();
     }
 
+    auto getRegisteredProcesses(EventType eventType) -> std::vector<int> {
+        std::vector<int> result;
+        auto ivt = getInterruptTable();
+        for(int i = 0; i < impl.interruptEntrysPerEventType;i++){
+            auto &entry= ivt[eventType * impl.interruptEntrysPerEventType + i];
+            if (entry.pid != 0) {
+                result.push_back(entry.pid);
+            }
+        }
+        return result;
+    }
+
 }
diff --git a/src/internal.hpp b/src/internal.hpp
index e1b5ea2..8eb6826 100644
--- a/src/internal.hpp
+++ b/src/internal.hpp
@@ -38,7 +38,7 @@ constexpr int keyboardBufferSize = 16;
         int textMode_font_height;
         int mouse_pos_x;
         int mouse_pos_y;
-        std::array<int16_t, keyboardBufferSize> keyboardBuffer;
+        std::array<int32_t, keyboardBufferSize> keyboardBuffer;
         int keyboardBuffer_index_write;
         int keyboardBuffer_index_read;
     };
@@ -61,10 +61,14 @@ constexpr int keyboardBufferSize = 16;
         std::vector<std::function<void()>> eventTable;
         bool localMemoryWarn = true;
         char *sharedMemory = nullptr;
+        std::vector<char> localSharedMemory;
     };
 
     extern Impl impl;
 
+
+    auto setDefaultValues() -> void;
+
 /**
  * send a signal to a process
  * @param pid of the process to which the signal is send
@@ -126,6 +130,12 @@ constexpr int keyboardBufferSize = 16;
  */
     auto buttonPressed(KeyCode keyCode) -> void;
 
+/**
+ * get registered Processes for a given event type.
+ * @param eventType.
+ */
+    auto getRegisteredProcesses(EventType eventType) -> std::vector<int>;
+
 // Shared Memory Layout
 // --------------------------------------------------------------------
 // struct ControlRegisters
diff --git a/src/log.cpp b/src/log.cpp
index c015f84..d7999c0 100644
--- a/src/log.cpp
+++ b/src/log.cpp
@@ -5,9 +5,15 @@
  */
 
 #include "log.hpp"
+#include <fstream>
 #include <iostream>
 
 namespace vkvm {
+
+    LogLevel logLevel = LogLevel::INFO;
+    LogLevel fileLogLevel = LogLevel::INFO;
+    std::ofstream logToFileStream;//NOLINT
+
     //converts the level to a string of the level
     auto getLevelName(LogLevel level) -> std::string {
         switch(level){
@@ -44,66 +50,98 @@ namespace vkvm {
         }
     }
 
-    LogLevel logLevel = LogLevel::INFO;
-
 //log the current time
-    auto logTime() -> void {
+    auto logTime() -> std::string {
         time_t rawtime;
         time(&rawtime);
         struct tm *timeinfo;
         timeinfo = localtime(&rawtime);
-
         constexpr int decimalBase = 10;
+        std::stringstream stream;
 
         if (timeinfo->tm_hour < decimalBase) {
-            std::cout << "0";
+            stream << "0";
         }
-        std::cout << timeinfo->tm_hour;
-        std::cout << ":";
+        stream << timeinfo->tm_hour;
+        stream << ":";
         if (timeinfo->tm_min < decimalBase) {
-            std::cout << "0";
+            stream << "0";
         }
-        std::cout << timeinfo->tm_min;
-        std::cout << ":";
+        stream << timeinfo->tm_min;
+        stream << ":";
         if (timeinfo->tm_sec < decimalBase) {
-            std::cout << "0";
+            stream << "0";
         }
-        std::cout << timeinfo->tm_sec;
+        stream << timeinfo->tm_sec;
+        return stream.str();
     }
 
 //log the message
     auto log(LogLevel level, const std::string &msg) -> void {
-        if(level >= logLevel) {
+        if(level >= logLevel || level >= fileLogLevel) {
             std::string levelName = getLevelName(level);
             const int maxLevelNameLength = 8;
 
-            //time
-            std::cout << "[";
-            logTime();
-            std::cout << "] ";
+            std::stringstream stream;
+            std::stringstream noColorStream;
 
-            //color and level name;lo
-            std::cout << "[";
-            std::cout << "\033[" << getLevelColor(level) << "m" << levelName << "\033[0m";
-            std::cout << "] ";
+            //time
+            std::string time = logTime();
+            stream << "[";
+            stream << time;
+            stream << "] ";
+
+            noColorStream << "[";
+            noColorStream << time;
+            noColorStream << "] ";
+
+            //color and level name
+            stream << "[";
+            stream << "\033[" << getLevelColor(level) << "m" << levelName << "\033[0m";
+            stream << "] ";
             for (int i = levelName.size(); i < maxLevelNameLength; i++) {
-                std::cout << " ";
+                stream << " ";
             }
 
+            //no color and level name
+            noColorStream << "[";
+            noColorStream << levelName;
+            noColorStream << "] ";
+            for (int i = levelName.size(); i < maxLevelNameLength; i++) {
+                noColorStream << " ";
+            }
+
+
+
             //message
             for(char c : msg){
                 if(c == '\n'){
                     //intend newlines so that they align with the start of the message
-                    std::cout << "\n";
+                    stream << "\n";
+                    noColorStream << "\n";
                     const int paddingSize = 22;
                     for(int i = 0; i < paddingSize;i++){
-                        std::cout << " ";
+                        stream << " ";
+                        noColorStream << " ";
                     }
                 }else{
-                    std::cout << c;
+                    stream << c;
+                    noColorStream << c;
+                }
+            }
+            stream << "\n";
+            noColorStream << "\n";
+
+            if(level >= logLevel){
+                std::cout << stream.str();
+            }
+            if(logToFileStream.is_open()){
+                if(level >= fileLogLevel){
+                    logToFileStream << noColorStream.str();
+                    //TODO(julian): fixme
+                    logToFileStream.flush();
                 }
             }
-            std::cout << "\n";
         }
     }
 
@@ -111,4 +149,17 @@ namespace vkvm {
         logLevel = level;
     }
 
+    auto setLogFileLevel(LogLevel level) -> void {
+        fileLogLevel = level;
+    }
+
+    auto setLogToFile(const std::string &file) -> void {
+        if(logToFileStream.is_open()){
+            logToFileStream.close();
+        }
+        if(!file.empty()){
+            logToFileStream.open(file, std::ofstream::app);
+        }
+    }
+
 }
diff --git a/src/log.hpp b/src/log.hpp
index 8d80990..1b40ad0 100644
--- a/src/log.hpp
+++ b/src/log.hpp
@@ -47,6 +47,8 @@ namespace vkvm {
  * @since 0.1.0
  */
     auto setLogLevel(LogLevel level) -> void;
+    auto setLogFileLevel(LogLevel level) -> void;
+    auto setLogToFile(const std::string &file) -> void;
 }
 
 #endif
diff --git a/src/vkvm.cpp b/src/vkvm.cpp
index df48721..5c03457 100644
--- a/src/vkvm.cpp
+++ b/src/vkvm.cpp
@@ -6,51 +6,32 @@
 #include <unistd.h>
 
 namespace vkvm {
-    // NOLINT
+
     auto initialize(int pid) -> void {
         impl.sharedMemoryPid = pid;
-        impl.sharedMemoryKey = 12345;// NOLINT
-        impl.sharedMemorySize = 8000;// NOLINT
+        impl.sharedMemoryKey = 12345;
+        impl.sharedMemorySize = 8000;
         initSemaphore();
         setDefaultValues();
     }
 
-    auto setDefaultValues() -> void {
-        impl.localMemoryWarn = false;
-        if(getSharedMemory() != nullptr) {
-            //set default values
-            setMode(GraphicMode::RGB);
-            setCharactersPerRow(60);// NOLINT
-            setCharactersPerColumn(20);// NOLINT
-            setHeight(600);// NOLINT
-            setWidth(800);// NOLINT
-            setMousePosition(42, 42);// NOLINT
-            setBackgroundColor(black);
-            setForegroundColor(white);
-            setRedrawInterval(20);// NOLINT
-            setTimerInterruptInterval(10);// NOLINT
-            setFont(FontType(3,"",0,0));
-        }
-        impl.localMemoryWarn = true;
-    }
-
     auto registerEvent(EventType type, const std::function<void()> &handler) -> bool {
         int signum = SIGUSR1 + impl.eventTable.size();
         auto ivt = getInterruptTable();
 
         lockSharedMemory();
 
-        for(int i = 0; i < impl.interruptEntrysPerEventType;i++){
-            auto &entry= ivt[type * impl.interruptEntrysPerEventType + i];
+        for (int i = 0; i < impl.interruptEntrysPerEventType; i++) {
+            auto &entry = ivt[type * impl.interruptEntrysPerEventType + i];
             if (entry.pid == 0) {
 
                 entry.pid = getpid();
                 entry.signum = signum;
                 impl.eventTable.push_back(handler);
 
-                onSignal(signum, [](int sig){
-                    if(sig >= SIGUSR1){
-                        if((sig - SIGUSR1) < impl.eventTable.size()){
+                onSignal(signum, [](int sig) {
+                    if (sig >= SIGUSR1) {
+                        if ((sig - SIGUSR1) < impl.eventTable.size()) {
                             impl.eventTable[sig - SIGUSR1]();
                         }
                     }
@@ -64,19 +45,24 @@ namespace vkvm {
     }
 
     auto setPixel(int x, int y, Color color) -> bool {
-        lockSharedMemory();
+        if(x < 0 || y < 0){
+            return false;
+        }
+        if (x > getWidth() || y > getHeight()) {
+            return false;
+        }
+        //lockSharedMemory();
         auto reg = getRegisters();
         const int bitsPerPixel = 8;
 
-        switch(reg->graphicMode) {
+        switch (reg->graphicMode) {
             case Text: {
                 int pixelIndex = (y * getWidth() + x);
                 unsigned char *ptr = reinterpret_cast<unsigned char *>(getPixelArea()) + (pixelIndex / bitsPerPixel);
-                if(color == reg->foreground_color){
+                if (color == reg->foreground_color) {
                     //set bit to 1
                     ptr[0] |= (1 << (pixelIndex % bitsPerPixel));
-                }
-                else{
+                } else {
                     //set bit to 0
                     ptr[0] &= ~(1 << (pixelIndex % bitsPerPixel));
                 }
@@ -85,11 +71,10 @@ namespace vkvm {
             case TwoColors: {
                 int pixelIndex = (y * getWidth() + x);
                 unsigned char *ptr = reinterpret_cast<unsigned char *>(getPixelArea()) + (pixelIndex / bitsPerPixel);
-                if(color == reg->foreground_color){
+                if (color.getRed() > 127 || color.getGreen() > 127 || color.getBlue() > 127) {
                     //set bit to 1
                     ptr[0] |= (1 << (pixelIndex % bitsPerPixel));
-                }
-                else{
+                } else {
                     //set bit to 0
                     ptr[0] &= ~(1 << (pixelIndex % bitsPerPixel));
                 }
@@ -110,24 +95,31 @@ namespace vkvm {
                 break;
             }
         }
-        unlockSharedMemory();
-        return false;
+        //unlockSharedMemory();
+        return true;
     }
 
     auto getPixel(int x, int y) -> Color {
-        Color color = Color(0,0,0);
+        if(x < 0 || y < 0) {
+            return getBackgroundColor();
+        }
+        if (x > getWidth() || y > getHeight()) {
+            return getBackgroundColor();
+        }
+
+        Color color = Color(0, 0, 0);
         auto reg = getRegisters();
         const int bitsPerPixel = 8;
 
-        switch(reg->graphicMode) {
+        switch (reg->graphicMode) {
             case Text: {
                 int pixelIndex = (y * getWidth() + x);
                 unsigned char *ptr = reinterpret_cast<unsigned char *>(getPixelArea()) + pixelIndex / bitsPerPixel;
                 bool bit = static_cast<bool>(ptr[0] & (1 << (pixelIndex % bitsPerPixel)));
-                if(bit){
+                if (bit) {
                     color = reg->foreground_color;
-                }else{
-                    color =reg->background_color;
+                } else {
+                    color = reg->background_color;
                 }
                 break;
             }
@@ -135,10 +127,10 @@ namespace vkvm {
                 int pixelIndex = (y * getWidth() + x);
                 unsigned char *ptr = reinterpret_cast<unsigned char *>(getPixelArea()) + (pixelIndex / bitsPerPixel);
                 bool bit = static_cast<bool>(ptr[0] & (1 << (pixelIndex % bitsPerPixel)));
-                if(bit){
+                if (bit) {
                     color = reg->foreground_color;
-                }else{
-                    color =reg->background_color;
+                } else {
+                    color = reg->background_color;
                 }
                 break;
             }
@@ -159,21 +151,35 @@ namespace vkvm {
     auto setText(std::string text) -> bool {
         lockSharedMemory();
         char *ptr = getTextArea();
-        for(int i = 0; i < static_cast<int>(text.size());i++){
-            if(i >= getCharactersPerColumn() * getCharactersPerRow()){
-                break;
+        for (int i = 0; i < static_cast<int>(text.size()); i++) {
+            if (i < getCharactersPerColumn() * getCharactersPerRow()) {
+                ptr[i] = text[i];
             }
-            ptr[i] = text[i];
         }
-        if(text.size() < getCharactersPerColumn() * getCharactersPerRow()){
+        if (text.size() < getCharactersPerColumn() * getCharactersPerRow()) {
             ptr[text.size()] = '\0';
         }
         unlockSharedMemory();
+        callEvent(EventType::RenderText);
         return true;
     }
 
     auto getText() -> std::string {
-        return std::string (getTextArea());
+        std::string text = getTextArea();
+
+        return text.substr(0, getCharactersPerColumn() * getCharactersPerRow());
+    }
+
+    auto clearText() -> bool {
+        lockSharedMemory();
+        char *ptr = getTextArea();
+        for (int i = 0; i < getCharactersPerColumn() * getCharactersPerRow(); ++i) {
+            ptr[i] = '\0';
+        }
+
+        unlockSharedMemory();
+        callEvent(EventType::RenderText);
+        return true;
     }
 
     auto getLayoutVersion() -> LayoutVersion {
@@ -181,7 +187,7 @@ namespace vkvm {
     }
 
     auto reset() -> void {
-        //TODO(julian): reset
+        setDefaultValues();
     }
 
     auto getWidth() -> int {
@@ -192,6 +198,7 @@ namespace vkvm {
         lockSharedMemory();
         getRegisters()->width_pixels = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getHeight() -> int {
@@ -202,6 +209,7 @@ namespace vkvm {
         lockSharedMemory();
         getRegisters()->height_pixels = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getMode() -> GraphicMode {
@@ -211,32 +219,33 @@ namespace vkvm {
     auto setMode(GraphicMode newValue) -> void {
         lockSharedMemory();
         auto reg = getRegisters();
-        if(reg->graphicMode != newValue){
+        if (reg->graphicMode != newValue) {
 
             std::vector<Color> pixels;
             int height = reg->height_pixels;
             int width = reg->width_pixels;
             pixels.resize(height * width);
 
-            for(int y = 0; y < height;y++){
-                for(int x = 0;x < width;x++){
-                    pixels[y * width + x] = getPixel(x,y);
+            for (int y = 0; y < height; y++) {
+                for (int x = 0; x < width; x++) {
+                    pixels[y * width + x] = getPixel(x, y);
                 }
             }
 
             getRegisters()->graphicMode = newValue;
 
             unlockSharedMemory();
-            for(int y = 0; y < height;y++){
-                for(int x = 0;x < width;x++){
-                    setPixel(x,y, pixels[y * width + x]);
+            for (int y = 0; y < height; y++) {
+                for (int x = 0; x < width; x++) {
+                    setPixel(x, y, pixels[y * width + x]);
                 }
             }
             lockSharedMemory();
-        }else{
+        } else {
             reg->graphicMode = newValue;
         }
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getRedrawInterval() -> int {
@@ -247,6 +256,7 @@ namespace vkvm {
         lockSharedMemory();
         getRegisters()->autoRedrawInterval = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getTimerInterruptInterval() -> int {
@@ -257,6 +267,7 @@ namespace vkvm {
         lockSharedMemory();
         getRegisters()->timerInterruptInterval = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getBackgroundColor() -> Color {
@@ -267,6 +278,7 @@ namespace vkvm {
         lockSharedMemory();
         getRegisters()->background_color = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getForegroundColor() -> Color {
@@ -277,6 +289,7 @@ namespace vkvm {
         lockSharedMemory();
         getRegisters()->foreground_color = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getCharactersPerRow() -> int {
@@ -288,15 +301,14 @@ namespace vkvm {
     }
 
     auto getFont() -> FontType {
-        //TODO(julian): get font properly
-        return {getRegisters()->textMode_font, "", 0, 0};
+        return FontType(getRegisters()->textMode_font);
     }
 
     auto setFont(const FontType &newValue) -> void {
-        //TODO(julian): setFont properly
         lockSharedMemory();
-        getRegisters()->textMode_font = newValue.getId();
+        getRegisters()->textMode_font = newValue;
         unlockSharedMemory();
+        callEvent(EventType::UpdateControlRegisters);
     }
 
     auto getMousePosition() -> Coordinates {
@@ -307,12 +319,15 @@ namespace vkvm {
         lockSharedMemory();
         auto keyCode = KeyCode(0);
         auto reg = getRegisters();
-        if(reg->keyboardBuffer_index_read != reg->keyboardBuffer_index_write) {
-            keyCode = static_cast<KeyCode>(reg->keyboardBuffer[reg->keyboardBuffer_index_read++]);
-            if (reg->keyboardBuffer_index_read >= sizeof(reg->keyboardBuffer)) {
-                reg->keyboardBuffer_index_read = 0;
-            }
+
+        if(reg->keyboardBuffer_index_read >= reg->keyboardBuffer_index_write) {
+            auto code = reg->keyboardBuffer[(reg->keyboardBuffer_index_read) % keyboardBufferSize];
+            keyCode = KeyCode(code);
+        }else{
+            auto code = reg->keyboardBuffer[(reg->keyboardBuffer_index_read) % keyboardBufferSize];
+            keyCode = KeyCode(code);
         }
+
         unlockSharedMemory();
         return keyCode;
     }
diff --git a/src/vkvm.hpp b/src/vkvm.hpp
index ed70601..7c50541 100644
--- a/src/vkvm.hpp
+++ b/src/vkvm.hpp
@@ -28,7 +28,6 @@ namespace vkvm {
  */
     auto initialize(int pid) -> void;
 
-    auto setDefaultValues() -> void;
 
 /**
  * set pixel at a x,y position to a certain color.
@@ -67,6 +66,13 @@ namespace vkvm {
  */
     auto getText() -> std::string;
 
+    /**
+     * clear text area
+     * @return if text could be cleared, false if it could not be cleared.
+     */
+    auto clearText() -> bool;
+
+
 //Control registers start here
 
 //all modes
diff --git a/test/area_test.cpp b/test/area_test.cpp
new file mode 100644
index 0000000..3306598
--- /dev/null
+++ b/test/area_test.cpp
@@ -0,0 +1,25 @@
+#include "../src/vkvm.hpp"
+#include <catch2/catch.hpp>
+
+TEST_CASE("AREA") {
+    vkvm::initialize(0);
+    vkvm::setWidth(200);
+    vkvm::setHeight(200);
+
+    SECTION("inside bounds") {
+        REQUIRE(vkvm::setPixel(100, 100, vkvm::white));
+        REQUIRE(vkvm::getPixel(100, 100) == vkvm::white);
+    }
+
+    SECTION("Out of bounds") {
+        REQUIRE_FALSE(vkvm::setPixel(400, 400, vkvm::white));
+        REQUIRE(vkvm::getPixel(400, 400) == vkvm::black);
+
+        REQUIRE_FALSE(vkvm::setPixel(-5, -5, vkvm::white));
+        REQUIRE(vkvm::getPixel(-5, -5) == vkvm::black);
+
+        vkvm::setBackgroundColor(vkvm::blue);
+
+        REQUIRE(vkvm::getPixel(400, 400) == vkvm::blue);
+    }
+}
\ No newline at end of file
diff --git a/test/buffer_test.cpp b/test/buffer_test.cpp
new file mode 100644
index 0000000..979d058
--- /dev/null
+++ b/test/buffer_test.cpp
@@ -0,0 +1,19 @@
+#include "../src/internal.hpp"
+#include "../src/vkvm.hpp"
+#include <catch2/catch.hpp>
+
+
+TEST_CASE("Keyboard Buffer") {
+    SECTION("write") {
+        vkvm::setLogLevel(vkvm::DEBUG);
+        //vkvm::buttonPressed(vkvm::A);
+        //vkvm::buttonPressed(vkvm::B);
+        //vkvm::buttonPressed(vkvm::C);
+    }
+
+    SECTION("read") {
+        //CHECK(vkvm::getLastPressedKey() == vkvm::C);
+        //CHECK(vkvm::getLastPressedKey() == vkvm::C);
+        //CHECK(vkvm::getLastPressedKey() == vkvm::C);
+    }
+}
\ No newline at end of file
diff --git a/test/color_test.cpp b/test/color_test.cpp
index 32154ff..ffd8703 100644
--- a/test/color_test.cpp
+++ b/test/color_test.cpp
@@ -4,45 +4,72 @@
 
 TEST_CASE("Colors") {
     vkvm::initialize(0);
-    vkvm::setPixel(10, 10, vkvm::black);//NOLINT
-    vkvm::setPixel(11, 11, vkvm::white);//NOLINT
-    vkvm::setPixel(12, 12, vkvm::green);//NOLINT
-    vkvm::setPixel(13, 13, vkvm::red);//NOLINT
-    vkvm::setPixel(14, 14, vkvm::blue);//NOLINT
-    vkvm::setPixel(15, 15, vkvm::Color(66, 77, 88)); //NOLINT
-    vkvm::setPixel(16, 16, vkvm::Color(0xFFFFFF));//NOLINT
+    vkvm::setMode(vkvm::RGB);
+    REQUIRE(vkvm::setPixel(10, 10, vkvm::black));
+    REQUIRE(vkvm::setPixel(11, 11, vkvm::white));
+    REQUIRE(vkvm::setPixel(12, 12, vkvm::green));
+    REQUIRE(vkvm::setPixel(13, 13, vkvm::red));
+    REQUIRE(vkvm::setPixel(14, 14, vkvm::blue));
+    REQUIRE(vkvm::setPixel(15, 15, vkvm::Color(66, 77, 88)));
+    REQUIRE(vkvm::setPixel(16, 16, vkvm::Color(0xFFFFFF)));
+    REQUIRE(vkvm::setPixel(17, 17, vkvm::Color(500, 500, 500)));
+    REQUIRE(vkvm::setPixel(18, 18, vkvm::Color(0x000000)));
 
     SECTION("RGB") {
-        REQUIRE(vkvm::getPixel(10, 10) == vkvm::black);//NOLINT
-        REQUIRE(vkvm::getPixel(11, 11) == vkvm::white);//NOLINT
-        REQUIRE(vkvm::getPixel(12, 12) == vkvm::green);//NOLINT
-        REQUIRE(vkvm::getPixel(13, 13) == vkvm::red);//NOLINT
-        REQUIRE(vkvm::getPixel(14, 14) == vkvm::blue);//NOLINT
-        REQUIRE(vkvm::getPixel(15, 15) == vkvm::Color(66, 77, 88));//NOLINT
-        REQUIRE(vkvm::getPixel(16, 16) == vkvm::white);//NOLINT
+        REQUIRE(vkvm::getPixel(10, 10) == vkvm::black);
+        REQUIRE(vkvm::getPixel(11, 11) == vkvm::white);
+        REQUIRE(vkvm::getPixel(12, 12) == vkvm::green);
+        REQUIRE(vkvm::getPixel(13, 13) == vkvm::red);
+        REQUIRE(vkvm::getPixel(14, 14) == vkvm::blue);
+        REQUIRE(vkvm::getPixel(15, 15) == vkvm::Color(66, 77, 88));
+        REQUIRE(vkvm::getPixel(16, 16) == vkvm::white);
+        REQUIRE(vkvm::getPixel(17, 17) == vkvm::white);
+        REQUIRE(vkvm::getPixel(18, 18) == vkvm::black);
     }
 
     SECTION("TwoColors") {
         vkvm::setMode(vkvm::TwoColors);
-        REQUIRE(vkvm::getPixel(10, 10) == vkvm::black);//NOLINT
-        REQUIRE(vkvm::getPixel(11, 11) == vkvm::white);//NOLINT
-        REQUIRE(vkvm::getPixel(12, 12) == vkvm::black);//NOLINT
-        REQUIRE(vkvm::getPixel(13, 13) == vkvm::black);//NOLINT
-        REQUIRE(vkvm::getPixel(14, 14) == vkvm::black);//NOLINT
-        REQUIRE(vkvm::getPixel(15, 15) == vkvm::black);//NOLINT
-        REQUIRE(vkvm::getPixel(16, 16) == vkvm::white);//NOLINT
+        REQUIRE(vkvm::getPixel(10, 10) == vkvm::black);
+        REQUIRE(vkvm::getPixel(11, 11) == vkvm::white);
+        REQUIRE(vkvm::getPixel(12, 12) == vkvm::white);
+        REQUIRE(vkvm::getPixel(13, 13) == vkvm::white);
+        REQUIRE(vkvm::getPixel(14, 14) == vkvm::white);
+        REQUIRE(vkvm::getPixel(15, 15) == vkvm::black);
+        REQUIRE(vkvm::getPixel(16, 16) == vkvm::white);
+        REQUIRE(vkvm::getPixel(17, 17) == vkvm::white);
+        REQUIRE(vkvm::getPixel(18, 18) == vkvm::black);
+
+
+        //different foreground/background color
+        vkvm::setBackgroundColor(vkvm::blue);
+        vkvm::setForegroundColor(vkvm::red);
+
+        REQUIRE(vkvm::getBackgroundColor() == vkvm::blue);
+        REQUIRE(vkvm::getForegroundColor() == vkvm::red);
+
+        REQUIRE(vkvm::getPixel(10, 10) == vkvm::blue);
+        REQUIRE(vkvm::getPixel(11, 11) == vkvm::red);
+        REQUIRE(vkvm::getPixel(12, 12) == vkvm::red);
+        REQUIRE(vkvm::getPixel(13, 13) == vkvm::red);
+        REQUIRE(vkvm::getPixel(14, 14) == vkvm::red);
+        REQUIRE(vkvm::getPixel(15, 15) == vkvm::blue);
+        REQUIRE(vkvm::getPixel(16, 16) == vkvm::red);
+        REQUIRE(vkvm::getPixel(17, 17) == vkvm::red);
+        REQUIRE(vkvm::getPixel(18, 18) == vkvm::blue);
 
     }
 
     SECTION("Gray256") {
         vkvm::setMode(vkvm::Gray_256);
-        REQUIRE(vkvm::getPixel(10, 10) == vkvm::black);//NOLINT
-        REQUIRE(vkvm::getPixel(11, 11) == vkvm::white);//NOLINT
-        REQUIRE(vkvm::getPixel(12, 12) == vkvm::Color(85, 85, 85));//NOLINT
-        REQUIRE(vkvm::getPixel(13, 13) == vkvm::Color(85, 85, 85));//NOLINT
-        REQUIRE(vkvm::getPixel(14, 14) == vkvm::Color(85, 85, 85));//NOLINT
-        REQUIRE(vkvm::getPixel(15, 15) == vkvm::Color(77, 77, 77));//NOLINT
-        REQUIRE(vkvm::getPixel(16, 16) == vkvm::white);//NOLINT
+        REQUIRE(vkvm::getPixel(10, 10) == vkvm::black);
+        REQUIRE(vkvm::getPixel(11, 11) == vkvm::white);
+        REQUIRE(vkvm::getPixel(12, 12) == vkvm::Color(85, 85, 85));
+        REQUIRE(vkvm::getPixel(13, 13) == vkvm::Color(85, 85, 85));
+        REQUIRE(vkvm::getPixel(14, 14) == vkvm::Color(85, 85, 85));
+        REQUIRE(vkvm::getPixel(15, 15) == vkvm::Color(77, 77, 77));
+        REQUIRE(vkvm::getPixel(16, 16) == vkvm::white);
+        REQUIRE(vkvm::getPixel(17, 17) == vkvm::white);
+        REQUIRE(vkvm::getPixel(18, 18) == vkvm::black);
     }
 
 }
diff --git a/test/default_test.cpp b/test/default_test.cpp
new file mode 100644
index 0000000..a5ca01e
--- /dev/null
+++ b/test/default_test.cpp
@@ -0,0 +1,70 @@
+#include "../src/internal.hpp"
+#include "../src/vkvm.hpp"
+#include <catch2/catch.hpp>
+
+TEST_CASE("Default values") {
+    vkvm::initialize(0);
+
+    SECTION("before") {
+        REQUIRE(vkvm::getMode() == vkvm::RGB);
+        REQUIRE(vkvm::getCharactersPerRow() == 60);
+        REQUIRE(vkvm::getCharactersPerColumn() == 20);
+        REQUIRE(vkvm::getHeight() == 600);
+        REQUIRE(vkvm::getWidth() == 800);
+        REQUIRE(vkvm::getMousePosition().x == 42);
+        REQUIRE(vkvm::getMousePosition().y == 42);
+        REQUIRE(vkvm::getBackgroundColor() == vkvm::black);
+        REQUIRE(vkvm::getForegroundColor() == vkvm::white);
+        REQUIRE(vkvm::getRedrawInterval() == 500);
+        REQUIRE(vkvm::getTimerInterruptInterval() == 1000);
+        REQUIRE(vkvm::getFont() == vkvm::ProFontIIX);
+    }
+
+    SECTION("change") {
+        vkvm::setMode(vkvm::TwoColors);
+        vkvm::setCharactersPerRow(100);
+        vkvm::setCharactersPerColumn(100);
+        vkvm::setHeight(40);
+        vkvm::setWidth(40);
+        vkvm::setMousePosition(41, 43);
+        vkvm::setBackgroundColor(vkvm::red);
+        vkvm::setForegroundColor(vkvm::blue);
+        vkvm::setRedrawInterval(1);
+        vkvm::setTimerInterruptInterval(2);
+        vkvm::setFont(vkvm::ProFontIIX);
+
+
+
+        REQUIRE(vkvm::getMode() == vkvm::TwoColors);
+        REQUIRE(vkvm::getCharactersPerRow() == 100);
+        REQUIRE(vkvm::getCharactersPerColumn() == 100);
+        REQUIRE(vkvm::getHeight() == 40);
+        REQUIRE(vkvm::getWidth() == 40);
+        REQUIRE(vkvm::getMousePosition().x == 41);
+        REQUIRE(vkvm::getMousePosition().y == 43);
+        REQUIRE(vkvm::getBackgroundColor() == vkvm::red);
+        REQUIRE(vkvm::getForegroundColor() == vkvm::blue);
+        REQUIRE(vkvm::getRedrawInterval() == 1);
+        REQUIRE(vkvm::getTimerInterruptInterval() == 2);
+        REQUIRE(vkvm::getFont() == vkvm::ProFontIIX);
+    }
+
+
+    SECTION("after") {
+        vkvm::reset();
+        REQUIRE(vkvm::getMode() == vkvm::RGB);
+        REQUIRE(vkvm::getCharactersPerRow() == 60);
+        REQUIRE(vkvm::getCharactersPerColumn() == 20);
+        REQUIRE(vkvm::getHeight() == 600);
+        REQUIRE(vkvm::getWidth() == 800);
+        REQUIRE(vkvm::getMousePosition().x == 42);
+        REQUIRE(vkvm::getMousePosition().y == 42);
+        REQUIRE(vkvm::getBackgroundColor() == vkvm::black);
+        REQUIRE(vkvm::getForegroundColor() == vkvm::white);
+        REQUIRE(vkvm::getRedrawInterval() == 500);
+        REQUIRE(vkvm::getTimerInterruptInterval() == 1000);
+        REQUIRE(vkvm::getFont() == vkvm::ProFontIIX);
+
+    }
+
+}
diff --git a/test/event_test.cpp b/test/event_test.cpp
new file mode 100644
index 0000000..64275c1
--- /dev/null
+++ b/test/event_test.cpp
@@ -0,0 +1,32 @@
+#include "../src/internal.hpp"
+#include "../src/vkvm.hpp"
+#include <catch2/catch.hpp>
+
+TEST_CASE("Event") {
+    vkvm::initialize(0);
+
+    SECTION("Register") {
+        bool mouseMove = false;
+        bool keyup = false;
+        bool keyup2 = false;
+        vkvm::registerEvent(vkvm::MouseMove, [&]() {
+            mouseMove = true;
+        });
+        vkvm::registerEvent(vkvm::KeyUp, [&]() {
+            keyup = true;
+        });
+        vkvm::registerEvent(vkvm::KeyUp, [&]() {
+            keyup2 = true;
+        });
+
+        REQUIRE_FALSE(mouseMove);
+        vkvm::callEvent(vkvm::MouseMove);
+        REQUIRE(mouseMove);
+
+        REQUIRE_FALSE(keyup);
+        REQUIRE_FALSE(keyup2);
+        vkvm::callEvent(vkvm::KeyUp);
+        REQUIRE(keyup);
+        REQUIRE(keyup2);
+    }
+}
diff --git a/test/public_test.cpp b/test/public_test.cpp
deleted file mode 100644
index 05f9467..0000000
--- a/test/public_test.cpp
+++ /dev/null
@@ -1,10 +0,0 @@
-#include "catch2/catch.hpp"
-#include "../src/vkvm.hpp"
-
-TEST_CASE("add works") {
-    vkvm::initialize(0);
-    vkvm::setText("Hello World");
-    SECTION("equals") {
-        REQUIRE(vkvm::getText() == "Hello World");
-    }
-}
\ No newline at end of file
diff --git a/test/text_test.cpp b/test/text_test.cpp
new file mode 100644
index 0000000..8996f16
--- /dev/null
+++ b/test/text_test.cpp
@@ -0,0 +1,28 @@
+#include "../src/internal.hpp"
+#include "../src/vkvm.hpp"
+#include <catch2/catch.hpp>
+
+TEST_CASE("Text") {
+    vkvm::initialize(0);
+
+    REQUIRE(vkvm::setText("Hello World, this is a test"));
+    REQUIRE(vkvm::getText() == "Hello World, this is a test");
+
+    REQUIRE(vkvm::setText("Hello World"));
+    REQUIRE(vkvm::getText() == "Hello World");
+
+    vkvm::setCharactersPerColumn(5);
+    vkvm::setCharactersPerRow(1);
+
+    REQUIRE(vkvm::clearText());
+
+    REQUIRE(vkvm::getCharactersPerColumn() == 5);
+    REQUIRE(vkvm::getCharactersPerRow() == 1);
+
+    REQUIRE(vkvm::setText("Hello World"));
+    REQUIRE(vkvm::getText() == "Hello");
+
+    REQUIRE(vkvm::clearText());
+
+    REQUIRE(vkvm::getText().empty());
+}
\ No newline at end of file