OS Chapter 1

If a diskless system downloads the OS at 5 MB/s and the OS image is 250 MB, how long will it take?

• 30 sec
• 45 sec
• 50 sec
• 60 sec

Time to load OS = 90 seconds. If OS is compressed to 60% and decompression takes 15 seconds, what's the new boot time?

• 54 sec
• 69 sec
• 60 sec
• 72 sec

An OS supports 3 types of users: admin (10%), power users (30%), and regular users (60%). If 500 users are logged in, how many are regular users?

• 300
• 250
• 200
• 100

Which of the following best describes multiprogramming?

• Executing multiple parts of one program
• Executing programs with multiple users
• Keeping multiple programs in memory simultaneously
• Executing programs without I/O support

In a multiprogramming system with 4 programs in memory, if each waits for I/O 20% of the time, what is the CPU utilization?

• 0.2
• 0.41
• 0.8
• 0.99

Which of the following is an example of spooling?

• Using RAM to print documents
• Storing print jobs in a queue
• Executing CPU-bound processes
• Managing swap memory

Spooling is primarily used to:

• Improve CPU throughput
• Manage printer I/O
• Optimize cache hits
• Avoid segmentation faults

The latency to synchronize between processors is 100 ns. For a program requiring 1000 synchronizations, what is total overhead?

• 100 µs
• 10 µs
• 1 ms
• 0.1 ms

In a multiprocessor system, communication overhead reduces performance by 15%. If ideal speedup is 20, what is actual speedup?

• 17
• 15
• 18
• 12

A parallel job on 32 processors takes 4 seconds, while on 1 processor it takes 120 seconds. What is efficiency?

• 0.9375
• 0.85
• 0.75
• 0.8