I/O scheduling and buffering in Operating Systems - Mini Project: Build & Apply

Understanding I/O Scheduling and Buffering

📖 Scenario: You are learning how computers manage input and output (I/O) operations efficiently. Imagine a printer receiving many print jobs or a hard drive handling multiple read and write requests. The operating system uses I/O scheduling and buffering to organize these tasks smoothly.

🎯 Goal: Build a simple model that shows how I/O requests are queued and buffered before being processed. This will help you understand the basic concepts of I/O scheduling and buffering in operating systems.

📋 What You'll Learn

Create a list of I/O requests with specific device names and request types

Add a buffer size limit variable to control how many requests can be held

Write a loop that simulates scheduling by selecting requests up to the buffer size

Complete the model by showing the final scheduled requests ready for processing

💡 Why This Matters

🌍 Real World

Operating systems use I/O scheduling and buffering to handle multiple device requests efficiently, preventing delays and improving performance.

💼 Career

Understanding these concepts is important for roles in system administration, software development, and IT support where managing hardware resources is key.

1

Create the list of I/O requests

Create a list called io_requests with these exact entries: {'device': 'Printer', 'type': 'Print'}, {'device': 'Disk', 'type': 'Read'}, {'device': 'Disk', 'type': 'Write'}, {'device': 'Network', 'type': 'Receive'}, {'device': 'Printer', 'type': 'Scan'}.

Operating Systems

# Create the list io_requests with the specified dictionaries
# Your code here

Need a hint?

Use a list with dictionaries inside. Each dictionary has keys 'device' and 'type'.

2

Set the buffer size limit

Create a variable called buffer_limit and set it to 3 to represent the maximum number of I/O requests that can be buffered at once.

Operating Systems

io_requests = [
    {'device': 'Printer', 'type': 'Print'},
    {'device': 'Disk', 'type': 'Read'},
    {'device': 'Disk', 'type': 'Write'},
    {'device': 'Network', 'type': 'Receive'},
    {'device': 'Printer', 'type': 'Scan'}
]
# Set buffer_limit to 3
# Your code here

Need a hint?

Just assign the number 3 to the variable buffer_limit.

3

Select requests up to the buffer limit

Create a list called scheduled_requests that contains the first buffer_limit entries from io_requests using list slicing.

Operating Systems

io_requests = [
    {'device': 'Printer', 'type': 'Print'},
    {'device': 'Disk', 'type': 'Read'},
    {'device': 'Disk', 'type': 'Write'},
    {'device': 'Network', 'type': 'Receive'},
    {'device': 'Printer', 'type': 'Scan'}
]
buffer_limit = 3
# Select the first buffer_limit requests into scheduled_requests
# Your code here

Need a hint?

Use list slicing like io_requests[:buffer_limit] to get the first few requests.

4

Complete the model by adding a processing flag

Add a new key 'status' with the value 'ready' to each dictionary in scheduled_requests using a for loop.

Operating Systems

io_requests = [
    {'device': 'Printer', 'type': 'Print'},
    {'device': 'Disk', 'type': 'Read'},
    {'device': 'Disk', 'type': 'Write'},
    {'device': 'Network', 'type': 'Receive'},
    {'device': 'Printer', 'type': 'Scan'}
]
buffer_limit = 3
scheduled_requests = io_requests[:buffer_limit]
# Add 'status': 'ready' to each scheduled request
# Your code here

Need a hint?

Use a for loop to add the key 'status' with value 'ready' to each dictionary.