Device Driver Emulator

CLI and GUI Based Implementation

Your Name
Department of Computer Science

May 29, 2025

Contents

1 Introduction 3
1.1 Project Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Technology Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 System Design 5
2.1 Architecture Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 CLI-Based Design (C++) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3 GUI-Based Design (Python) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Module Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 CLI Implementation (C++) 7

3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2 File: main4.cpp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.1 Function Declarations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.2 Main Menu Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2.3 CLI Screenshots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 GUI Implementation (Python) 10

4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2 File: emulator33.py . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.1 Class and Function Declarations . . . . . . . . . . . . . . . . . . . . . . . 10
4.3 GUI Screenshots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5 Modules and Functionalities 15

5.1 Keyboard Driver Emulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2 Mouse Driver Emulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.3 Disk Driver Emulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.4 Cross-Module Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

6 Testing and Results 17

6.1 Test Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.2 Expected vs Actual Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.3 Performance Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.4 Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

7 Conclusion 19
7.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.2 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.3 Future Enhancements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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7.4 Final Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

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Chapter 1

Introduction

1.1 Project Overview

The Device Driver Emulator project is a comprehensive simulation of low-level device in-
teractions typically handled by operating system drivers. Implemented in both C++ (for CLI
interaction) and Python (for GUI interaction via Tkinter), the emulator provides functionality
to simulate three core device categories:

• Mouse Driver – Move, click, scroll, and track the cursor position.

• Keyboard Driver – Detect keystrokes, calculate key hold time, and display ASCII codes.

• Disk Driver – Simulate block-level read/write operations, LRU caching, defragmentation,

block copy/move, and formatting.

Both versions encapsulate key device behaviors, log user interactions, and demonstrate driver-
level I/O operations in a high-level environment for educational and experimental purposes.

1.2 Motivation
Device drivers are a cornerstone of operating system design. However, their real-world develop-
ment involves kernel-space coding, making learning and experimentation difficult for students.
This emulator bridges that gap by:

• Providing a user-space simulation that mimics real device drivers.

• Enabling interactive experimentation without requiring kernel-level access.

• Offering dual interfaces—command-line and graphical—to cater to different user prefer-

ences and learning styles.

1.3 Objectives
The primary objectives of the Device Driver Emulator are:

1. To emulate core behaviors of mouse, keyboard, and disk drivers.

2. To support both CLI and GUI interfaces with similar functional capabilities.

3. To provide detailed logs for each operation for monitoring and debugging.

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 4. To demonstrate how device-level tasks can be modularized and abstracted.

5. To serve as a pedagogical tool in understanding device-driver development principles.

1.4 Key Features

• C++ CLI Version:

– Uses Windows API (‘windows.h‘) to emulate device interactions.

– Threaded input capture and event logging.
– File-based activity logging for diagnostics.

• Python GUI Version:

– Uses Tkinter for interactive graphical controls.

– Real-time visual feedback for mouse and keyboard actions.
– Disk memory visualization and operations via canvas interface.

1.5 Technology Stack

• C++ Version:

– Language: C++17
– Platform: Windows
– Libraries: Windows.h, Thread, Chrono, iostream

• Python Version:

– Language: Python 3.13

– Libraries: Tkinter, os, subprocess, time, random

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Chapter 2

System Design

2.1 Architecture Overview

The Device Driver Emulator is designed using a layered modular architecture that separates
interface logic from core device functionalities. This approach ensures maintainability, scalability,
and flexibility across both the CLI and GUI implementations.
The system is divided into three primary components:

• Interface Layer – Handles user interaction via CLI (C++) or GUI (Python Tkinter).

• Driver Emulation Layer – Contains logic for mouse, keyboard, and disk emulation.

• Logging and Utility Layer – Responsible for log tracking, cache management, and
utility operations.

2.2 CLI-Based Design (C++)

The command-line implementation is designed using object-oriented C++ and follows a menu-
driven interaction model. Key design considerations include:

• Multi-threading for keyboard event capture and processing.

• Real-time input handling using Windows console APIs.

• Separation of command parsing and device logic.

• Logging every action using a thread-safe file stream.

Main Components:

• MouseDriverEmulator – Mouse position, click, and scroll emulation.

• DiskDriver – Block read/write, cache access, formatting, defragmentation.

• Keyboard Input Processor – Captures key press/release, calculates hold duration.

• LRUCache – Manages frequently accessed disk blocks for efficiency.

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2.3 GUI-Based Design (Python)
The graphical interface is built using Python’s Tkinter library, providing a rich and interactive
user experience. Each emulator is encapsulated in a dedicated window.
Design Characteristics:

• Gradient buttons, canvas-based visual elements.

• Use of modal dialogs for input.

• Interactive animations for mouse movements and disk block changes.

Main Classes:

• MouseDriverEmulator – Displays and updates cursor location, handles clicks and scrolls.

• VirtualKeyboard – Renders a virtual keyboard, shows ASCII and press duration.

• DiskDriverEmulator – Simulates 1024 disk blocks, LRU cache behavior, and I/O ops.

• EmulatorApp – Manages main GUI menu and window navigation.

2.4 Module Overview

Each emulator module implements a consistent interface across both CLI and GUI environments.
The goal is to ensure:

• Functional parity across implementations.

• Clear modular boundaries and separation of concerns.

• Easy extension or refactoring of individual device drivers.

Table 2.1: Functional Comparison of CLI and GUI Modules

Functionality CLI (C++) GUI (Python)

Mouse Movement Yes Yes
Mouse Click/Scroll Yes Yes
Keyboard Logging Yes Yes
Disk Block I/O Yes Yes
Cache (LRU) Simulation Yes Yes
Visual Feedback No Yes
Multi-threading Yes No
Log File Generation Yes No (console-based)

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 Chapter 3

CLI Implementation (C++)

3.1 Overview
The CLI version of the emulator is implemented in C++ using the Windows API. It features a
menu-driven interface for emulating mouse, keyboard, and disk driver functionalities. The sys-
tem uses multi-threading, synchronization primitives (mutex, condition variable), and structured
logging to simulate realistic device behavior.

3.2 File: main4.cpp

3.2.1 Function Declarations
Below is a listing of key function declarations used in the CLI implementation. These functions
are grouped by their respective modules.

MouseDriverEmulator

Listing 3.1: MouseDriverEmulator - Mouse Operations

1 void moveMouse ( int x , int y ) ;
2 void clickMouse ( const std :: string & type ) ;
3 void scrollMouse ( int amount ) ;
4 void getMousePosition () ;

Keyboard Emulation

Listing 3.2: Keyboard Input Handlers

1 void pr oces s K e y b o a r d E v e n t s () ;
2 void captur e K e y b o a r d I n p u t () ;

DiskDriver

Listing 3.3: DiskDriver - Disk Operations

1 void writeBlock ( int blockID , const std :: string & data ) ;
2 void readBlock ( int blockID ) ;
3 void formatDisk () ;
4 void freeBlock ( const std :: string & blockIDs ) ;

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5 void moveBlock ( const std :: string & sourceIDs , int startDestID ) ;
6 void copyBlock ( int sourceID , const std :: string & destIDs ) ;
7 void defragmentDisk () ;

Utility Functions and Structures

Listing 3.4: Utility Structures and Logging

1 void logAction ( const std :: string & action ) ;
2

3 class LRUCache {
4 void accessBlock ( int blockID , DiskBlock block ) ;
5 bool getBlock ( int blockID , DiskBlock & block ) ;
6 };
7

8 class DiskBlock {
9 int blockID ;
10 char data [ BLOCK_SIZE ];
11 };

3.2.2 Main Menu Loop

The main() function initializes the emulator and provides the main interaction menu. Based on
the user’s input, it spawns appropriate threads or executes device-specific handlers.
Listing 3.5: Main Function Entry
1 int main () {
2 logAction ( " Emulator ␣ started " ) ;
3 ...
4 switch ( choice ) {
5 case 1: // Mouse Emulator
6 case 2: // Keyboard Emulator
7 case 3: // Disk Emulator
8 case 4: // Exit
9 }
10 }

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3.2.3 CLI Screenshots

Figure 3.1: Command-Line Interface of Device Driver Emulator

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 Chapter 4

GUI Implementation (Python)

4.1 Overview
The Python-based implementation of the Device Driver Emulator provides an interactive and
visually engaging graphical interface using the Tkinter library. It consists of three main device
modules:

• Mouse Driver Emulator

• Keyboard Driver Emulator

• Disk Driver Emulator

Users can access these emulators from a central control menu. Each module leverages object-
oriented programming, canvas-based animations, dialog-based I/O, and dynamic component
updates for an immersive experience.

4.2 File: emulator33.py

4.2.1 Class and Function Declarations
The following sections detail the core classes and their key methods involved in GUI simulation.

MouseDriverEmulator

Listing 4.1: MouseDriverEmulator - Mouse Interaction GUI

1 class Mouse D ri v e rE m u la t o r :
2 def __init__ ( self , master )
3 def u pd a t e _ p o s i t i o n _ l a b e l ( self )
4 def tra c k _ m o u s e _ p o s i t i o n ( self , event )
5 def sh o w _ p o s i t i o n _ o n _ c l i c k ( self , event )
6 def move_mouse ( self )
7 def click_mouse ( self )
8 def scroll_mouse ( self )
9 def get_position ( self )

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 VirtualKeyboard

Listing 4.2: VirtualKeyboard - Key Simulation

1 class VirtualKeyboard ( tk . Tk ) :
2 def __init__ ( self )
3 def create_keyboard ( self )
4 def on_real _key_p ress ( self , event )
5 def on_r e a l_ k e y_ r e le a s e ( self , event )
6 def on_press ( self , key )
7 def on_release ( self , key )
8 def update_label ( self , key , elapsed )
9 def clear_label ( self )
10 def schedule_update ( self , key )

DiskDriverEmulator

Listing 4.3: DiskDriverEmulator - Disk Simulation

1 class DiskDr iv er Em ul at or :
2 def __init__ ( self , master )
3 def create_disk_map ( self )
4 def update_disk_map ( self )
5 def update_output ( self , message )
6 def write_block ( self )
7 def read_block ( self )
8 def copy_block ( self )
9 def defragment_disk ( self )
10 def format_disk ( self )
11 def free_block ( self )
12 def move_block ( self )

Main Application Menu

Listing 4.4: EmulatorApp - Main Menu

1 class EmulatorApp :
2 def __init__ ( self , root )
3 def run_mouse ( self )
4 def run_keyboard ( self )
5 def run_disk ( self )

Program Entry

Listing 4.5: Main Entry Point

1 def main ()

4.3 GUI Screenshots

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Figure 4.1: Preface

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 Figure 4.2: Mouse Driver

Figure 4.3: Keyboard Driver

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Figure 4.4: Disk Driver

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Chapter 5

Modules and Functionalities

This chapter provides a breakdown of the three core device driver emulation modules included
in the project—Mouse, Keyboard, and Disk—and highlights their respective functionalities and
behaviors in both CLI (C++) and GUI (Python) versions.

5.1 Keyboard Driver Emulator

The Keyboard Driver Emulator simulates the behavior of key presses, including:
• Capturing key press and release events.

• Logging ASCII values and virtual key codes.

• Measuring the duration for which a key is held.

CLI Features
• Multi-threaded input capture using ReadConsoleInput.

• Press/release logging with time measurement via chrono.

• Stops upon ESC key press.

GUI Features
• Virtual keyboard with dynamic button highlighting.

• Real-time display of pressed key, ASCII code, and hold time.

• Interactive layout styled with ttk and keyboard row configuration.

5.2 Mouse Driver Emulator

The Mouse Driver Emulator offers functionality to simulate and visualize:
• Cursor movement to specific coordinates.

• Left, right, and middle click actions.

• Scrolling using delta values.

• Tracking current mouse position.

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CLI Features
• Uses SetCursorPos and SendInput from the Windows API.
• Input commands like move, click, scroll, and position.
• All actions are logged to emulator log.txt.

GUI Features
• Canvas-based simulation with animated cursor and click feedback.
• Visual trail for scroll direction and amount.
• Dialog-based controls for input, file selection, and code execution.

5.3 Disk Driver Emulator

The Disk Driver Emulator simulates block-level disk operations and memory caching:
• Write, read, format, copy, and move disk blocks.
• Simulates a Least Recently Used (LRU) cache mechanism.
• Visualizes 60 active blocks out of 1024 total in GUI mode.

CLI Features
• DiskDriver class manages 1024 blocks.
• Block data stored in a struct and accessed through vector-based disk.
• LRU cache implemented via a custom class and accessed by disk operations.
• Supports freeing, moving, copying, and defragmenting blocks.

GUI Features
• Visual disk map rendered on Tkinter canvas.
• Block states: White (empty), Green (data), Red (cached).
• Console log for operation feedback and output.
• Dialog-based interaction for block selection and data entry.

5.4 Cross-Module Integration

Each module was designed to be self-contained yet consistent in design across CLI and GUI
implementations. Key design patterns and features include:
• Abstraction of user interaction logic from core functionality.
• Persistent logging in CLI and real-time feedback in GUI.
• Parity in supported operations to ensure a fair learning comparison.
• Modular class-based architecture supporting easy extensions.

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Chapter 6

Testing and Results

6.1 Test Scenarios

To verify the correctness and stability of the Device Driver Emulator, both the CLI and GUI
versions were tested under various scenarios for all three modules. Each test focused on functional
integrity, edge case handling, and consistency of behavior.

Mouse Driver Tests

• Moving the cursor to screen corners and center positions.

• Testing all click types (left, right, middle) including invalid input.

• Scrolling in both directions with small and large deltas.

• Retrieving and displaying current cursor position.

Keyboard Driver Tests

• Pressing standard alphanumeric and special keys.

• Holding keys for varying durations and observing measured time.

• Triggering emulator shutdown with ESC key (CLI).

• Simultaneous GUI interaction and real key press events.

Disk Driver Tests

• Writing and reading data across multiple blocks.

• Copying from a source to multiple destination blocks.

• Moving blocks with overlaps and verifying integrity.

• Defragmentation after random data allocation.

• Attempting operations on invalid or out-of-range block IDs.

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 Table 6.1: Test Outcome Summary

Test Case Expected Result Actual Result

Mouse move to (100,100) Cursor moves and logs action Success
Mouse click (right) Red click feedback shown Success
Key press ’A’ ASCII and hold time logged Success
Write to block 512 Data stored and marked green Success
Copy invalid block ID Error shown / ignored Success
Defragmentation Data compacted and mapped left Success

6.2 Expected vs Actual Results

All modules behaved as expected. Edge cases were handled gracefully through error messages
(GUI) or log warnings (CLI).

6.3 Performance Metrics

• CLI Latency: 10ms average command processing time.

• GUI Response: Instantaneous input reaction, with rendering delay <30ms.

• Disk Emulator Throughput: 100 ops/sec for sequential block I/O in memory.

• Memory Usage: Within 100MB (GUI) and 30MB (CLI).

6.4 Error Handling

• Input validation performed on all interactive fields.

• CLI logs unknown commands and invalid formats.

• GUI shows popup messages for exceptions or rule violations.

• Robust exception handling in subprocess and file access routines.

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Chapter 7

Conclusion

7.1 Summary
The Device Driver Emulator project successfully demonstrates the simulation of core device
driver behaviors—mouse, keyboard, and disk—via both command-line (C++) and graphical
(Python) interfaces. Through this emulator, we have created an accessible and interactive
platform for understanding how low-level device operations are abstracted and controlled in
operating systems.
Key accomplishments include:

• Dual-interface implementation offering CLI (C++) and GUI (Python) modes.

• Full-featured mouse, keyboard, and disk emulators with real-time interaction.

• Visual feedback for GUI users and persistent logging for CLI users.

• Modular design allowing easy expansion and maintenance.

7.2 Challenges
While developing the emulator, several challenges were encountered and resolved:

• Thread synchronization in the CLI version required careful use of mutexes and condition
variables to avoid race conditions during keyboard input.

• Cross-platform limitations due to reliance on Windows-specific APIs in C++, restrict-

ing the CLI version to Windows environments.

• GUI complexity in dynamically updating the canvas, especially for visual elements like
disk blocks and mouse trails, required fine control of event handling.

• Error handling and validation to ensure robustness during unpredictable user input
or file operations.

7.3 Future Enhancements

The project opens doors to multiple future directions and extensions:

• Cross-platform CLI using libraries like ncurses or moving to cross-platform abstractions

for keyboard and mouse input.

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 • Persistent disk image storage allowing users to save and reload disk states across
sessions.

• Advanced caching strategies like FIFO, LFU, or adaptive caches.

• Support for additional drivers such as printer, display, or network driver simulation.

• Exportable logs and reports from GUI mode for better integration with diagnostics or
grading tools.

7.4 Final Remarks

This emulator not only replicates technical behaviors of device drivers but also encourages ex-
ploration, testing, and learning in a safe and controlled environment. Whether as an educational
tool or a proof-of-concept system-level simulation, the Device Driver Emulator bridges the gap
between hardware theory and implementation practice.

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