diff --git a/cmd/root.go b/cmd/root.go
index 846886c..8167a53 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -52,6 +52,9 @@ func runRootCommand(cmd *cobra.Command, args []string) error {
 	if err != nil {
 		return err
 	}
-	hal.NewHALModule(program, 256, debug)
-	return nil
+	module, err := hal.NewHALModule(program, 256, 2, debug)
+	if err != nil {
+		return err
+	}
+	return module.Run()
 }
diff --git a/hal/instructions.go b/hal/instructions.go
index 043c272..7e64679 100644
--- a/hal/instructions.go
+++ b/hal/instructions.go
@@ -59,8 +59,8 @@ var InstructionStop = &Instruction{
 
 var InstructionOut = &Instruction{
 	Name: "OUT",
-	Execute: func(module *Module) {
-		// TODO implement
+	ExecuteWithOperand: func(module *Module, operand float64) {
+		module.IO[int64(operand)] = module.accumulator
 	},
 }
 
diff --git a/hal/module.go b/hal/module.go
index d4b4779..8f33a12 100644
--- a/hal/module.go
+++ b/hal/module.go
@@ -7,20 +7,21 @@ const maxInstructions = 1000
 type Program map[int64]*ProgrammedInstruction
 
 type Module struct {
-	Accumulator    float64
-	ProgramStorage Program
-	Register       []float64
+	accumulator    float64
+	programStorage Program
+	register       []float64
+	IO             []float64
 
 	isStopped    bool
 	debugEnabled bool
 }
 
 func (h *Module) ProgramCounter() int64 {
-	return int64(h.Register[0])
+	return int64(h.register[0])
 }
 
 func (h *Module) increaseProgramCounter() {
-	h.Register[0]++
+	h.register[0]++
 }
 
 func (h *Module) debug(format string, args ...interface{}) {
@@ -31,15 +32,15 @@ func (h *Module) debug(format string, args ...interface{}) {
 }
 
 func (h *Module) Step() {
-	instruction := h.ProgramStorage[h.ProgramCounter()]
+	instruction := h.programStorage[h.ProgramCounter()]
 	h.increaseProgramCounter()
 	if instruction == nil {
 		return
 	}
 	h.debug("Instruction: %s", instruction.Instruction.Name)
-	h.debug("Accumulator before: %d", h.Accumulator)
+	h.debug("Accumulator before: %d", h.accumulator)
 	instruction.Execute(h)
-	h.debug("Accumulator after: %d", h.Accumulator)
+	h.debug("Accumulator after: %d", h.accumulator)
 }
 
 func (h *Module) Run() error {
@@ -52,13 +53,14 @@ func (h *Module) Run() error {
 	return nil
 }
 
-func NewHALModule(program Program, registerSize uint64, debug bool) (*Module, error) {
+func NewHALModule(program Program, registerSize uint64, ioSize uint64, debug bool) (*Module, error) {
 	if registerSize <= 10 {
 		return nil, fmt.Errorf("register size must be greater then 10 [ registerSize = %d ]", registerSize)
 	}
 	return &Module{
-		ProgramStorage: program,
-		Register:       make([]float64, registerSize),
+		programStorage: program,
+		register:       make([]float64, registerSize),
+		IO:             make([]float64, ioSize),
 		debugEnabled:   debug,
 	}, nil
 }