Disk Scheduling Simulator

This repository contains both Python and C++ implementations of a disk scheduling simulator for educational purposes.

Files

• disk.py - Original Python implementation (requires tkinter for graphics)

• disk.cpp - C++ implementation (console-only)

• Makefile - Build file for C++ version

Building the C++ Version

make

This will compile disk.cpp into an executable called disk.

Usage

C++ Version

Run the simulator with default settings:

./disk -c

Command-Line Options

• -s, --seed <N> - Random seed (default: 0)

• -a, --addr <LIST> - Request list (comma-separated) or -1 for random

• -A, --addrDesc <DESC> - Address descriptor: numRequests,maxRequest,minRequest (default: "5,-1,0")

• -S, --seekSpeed <N> - Speed of seek (default: 1)

• -R, --rotSpeed <N> - Speed of rotation (default: 1)

• -p, --policy <POLICY> - Scheduling policy: FIFO, SSTF, SATF, BSATF (default: FIFO)

• -w, --schedWindow <N> - Scheduling window size, -1 for all (default: -1)

• -o, --skewOffset <N> - Skew offset in blocks (default: 0)

• -z, --zoning <ZONES> - Angles between blocks on outer,middle,inner tracks (default: "30,30,30")

• -c, --compute - Show computed results

• -l, --lateAddr <LIST> - Late arriving requests

• -L, --lateAddrDesc <DESC> - Late address descriptor (default: "0,-1,0")

Examples

Test FIFO scheduling:

./disk -c -s 0 -p FIFO

Test SATF (Shortest Access Time First) scheduling:

./disk -c -s 0 -p SATF

Test SSTF (Shortest Seek Time First) scheduling:

./disk -c -s 0 -p SSTF

Specify custom requests:

./disk -c -a 10,15,20,5,18

Generate 10 random requests:

./disk -c -A 10,-1,0

Scheduling Policies

• FIFO - First In First Out (processes requests in order)

• SSTF - Shortest Seek Time First (minimizes seek distance)

• SATF - Shortest Access Time First (minimizes total access time)

• BSATF - Bounded SATF (SATF with fairness window)

Output

The simulator outputs:

• Seek time - Time spent moving the disk arm between tracks

• Rotate time - Time spent waiting for the platter to rotate

• Transfer time - Time spent reading/writing data

• Total time - Sum of all times

Example output:

Block:   8  Seek:  0  Rotate: 45  Transfer: 30  Total:  75

Block:  11  Seek:  0  Rotate: 60  Transfer: 30  Total:  90

Block:   2  Seek:  0  Rotate: 60  Transfer: 30  Total:  90

Block:  15  Seek: 80  Rotate:280  Transfer: 30  Total: 390

Block:  18  Seek:  0  Rotate: 60  Transfer: 30  Total:  90

 

TOTALS      Seek: 80  Rotate:505  Transfer:150  Total: 735

Differences from Python Version

• Graphics not supported (Python version uses Tkinter)

• Console output only

• Same simulation logic and algorithms

• Identical numerical results

Cleaning Up

To remove compiled files:

make clean