Virtual Memory Manager

👀 Overview

This project implements a Virtual Memory Manager based on concepts from "Operating System Concepts" by Silberschatz, et al., 10th edition, page P-51. The implementation focuses on translating logical addresses into physical addresses using specific requirements and modifications detailed below.

🔧 Implementation Details

Input File Format

The program reads a file containing several 32-bit integer numbers representing logical addresses. It processes each address by masking the rightmost 16 bits to extract an 8-bit page number and an 8-bit page offset.

Address Translation

Using a TLB (Translation Lookaside Buffer) and a page table, the program translates each logical address into its corresponding physical address. The virtual address space size is 216 = 65,536 bytes.

Page Replacement Algorithm

• TLB (Translation Lookaside Buffer):

  • 16 entries with a FIFO (First-In, First-Out) replacement strategy.

• Page Table:

  • 256 entries to map logical page numbers to physical frame numbers.

Output

For each translated physical address, the program retrieves and outputs the byte stored at that address in physical memory.

📋 Specifications

• Page Table:
  • 256 entries
• Page Size:
  • 256 bytes
• TLB Entries:
  • 16 entries
• Frame Size:
  • 256 bytes
• Physical Memory:
  • 65,536 bytes (256 frames × 256-byte frame size)

🛠️ Build Instructions

1. Ensure you are on a Linux, Unix, or macOS system.
2. Generate the executable vm by compiling it using:

   make

⚙️ Execution

Run the compiled executable with the input file:

• For First-in First-Out Replacement (fifo):

  ./vm addresses.txt fifo

• For Least Recently Used (lru):

  ./vm addresses.txt lru

📥 Example Input

For example, given an input file named addresses.txt with the following content:

16916
62493
30198
53683
40185
28781
24462
48399
64815
18295
12218
22760
57982
27966
54894
38929
32865
64243
2315

📤 Output File

The output for the provided input should be named as correct.txt and have the following format:

Virtual address: 16916 TLB: 0 Physical address: 20 Value: 0
Virtual address: 62493 TLB: 1 Physical address: 285 Value: 0
Virtual address: 30198 TLB: 2 Physical address: 758 Value: 29
Virtual address: 53683 TLB: 3 Physical address: 947 Value: 108
Virtual address: 40185 TLB: 4 Physical address: 1273 Value: 0
Virtual address: 28781 TLB: 5 Physical address: 1389 Value: 0
Virtual address: 24462 TLB: 6 Physical address: 1678 Value: 23
Virtual address: 48399 TLB: 7 Physical address: 1807 Value: 67
Virtual address: 64815 TLB: 8 Physical address: 2095 Value: 75
Virtual address: 18295 TLB: 9 Physical address: 2423 Value: -35
Virtual address: 12218 TLB: 10 Physical address: 2746 Value: 11
Virtual address: 22760 TLB: 11 Physical address: 3048 Value: 0
Virtual address: 57982 TLB: 12 Physical address: 3198 Value: 56
Virtual address: 27966 TLB: 13 Physical address: 3390 Value: 27
Virtual address: 54894 TLB: 14 Physical address: 3694 Value: 53
Virtual address: 38929 TLB: 15 Physical address: 3857 Value: 0
Virtual address: 32865 TLB: 0 Physical address: 4193 Value: 0
Virtual address: 64243 TLB: 1 Physical address: 4595 Value: -68
Virtual address: 2315 TLB: 2 Physical address: 4619 Value: 66
Number of Translated Addresses = 19
Page Faults = 19
Page Fault Rate = 1.000
TLB Hits = 0
TLB Hit Rate = 0.000

🧪 Test Instructions

• First, ensure the file has execution permissions. You can do this with the chmod command:

  chmod +x test.sh

• Then you need to generate the executable by running the command:

  make

• After that, you can run the script with the command:
  • If you want to run all tests:

    ./run.sh all

  • If you want to run a specific test:
    • ./run.sh [number_of_test]

       ./run.sh 5

• If there are differences in your result, it will print these errors in the diff folder with the name of the file that had the difference. The line starting with < is the received result, and the line starting with > is the expected result.
• The folder should be organized as follows:

   .
   ├── Makefile
   ├── vm.c
   ├── BACKING_STORE.bin
   ├── run.sh
   ├── test
   │   ├── 1
   │   │   ├── addresses_1.txt
   │   │   ├── addresses_1_fifo.txt
   │   │   ├── addresses_1_lru.txt
   │   ├── N
   │   │   ├── addresses_N.txt
   │   │   ├── addresses_N_fifo.txt
   │   │   ├── addresses_N_lru.txt