WorksheetsOS Chapter 1
Total questions: 50
Worksheet time: 4mins
Name
Class
Date
1.
If a diskless system downloads the OS at 5 MB/s and the OS image is 250 MB, how long will it take?
a)
30 sec
b)
45 sec
c)
50 sec
d)
60 sec
2.
Time to load OS = 90 seconds. If OS is compressed to 60% and decompression takes 15 seconds, what's the new boot time?
a)
54 sec
b)
69 sec
c)
60 sec
d)
72 sec
3.
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?
a)
300
b)
250
c)
200
d)
100
4.
Which of the following best describes multiprogramming?
a)
Executing multiple parts of one program
b)
Executing programs with multiple users
c)
Keeping multiple programs in memory simultaneously
d)
Executing programs without I/O support
5.
In a multiprogramming system with 4 programs in memory, if each waits for I/O 20% of the time, what is the CPU utilization?
a)
0.2
b)
0.41
c)
0.8
d)
0.99
6.
Which of the following is an example of spooling?
a)
Using RAM to print documents
b)
Storing print jobs in a queue
c)
Executing CPU-bound processes
d)
Managing swap memory
7.
Spooling is primarily used to:
a)
Improve CPU throughput
b)
Manage printer I/O
c)
Optimize cache hits
d)
Avoid segmentation faults
8.
The latency to synchronize between processors is 100 ns. For a program requiring 1000 synchronizations, what is total overhead?
a)
100 µs
b)
10 µs
c)
1 ms
d)
0.1 ms
9.
In a multiprocessor system, communication overhead reduces performance by 15%. If ideal speedup is 20, what is actual speedup?
a)
17
b)
15
c)
18
d)
12
10.
A parallel job on 32 processors takes 4 seconds, while on 1 processor it takes 120 seconds. What is efficiency?
a)
0.9375
b)
0.85
c)
0.75
d)
0.8
11.
In a distributed system, if message latency is 10 ms and average processing time per node is 5 ms, what is total response time for 4 nodes sequentially communicating?
a)
60 ms
b)
50 ms
c)
40 ms
d)
45 ms
12.
A distributed system has 5 nodes with 99.9% availability each. What is overall system availability assuming all nodes must be up?
a)
0.995
b)
0.9999
c)
0.995
d)
0.9999
13.
For a distributed transaction, prepare phase takes 100 ms, commit phase takes 150 ms, and network delay per message is 10 ms. Total 6 messages exchanged. What is total transaction time?
a)
310 ms
b)
360 ms
c)
370 ms
d)
300 ms
14.
A distributed hash table (DHT) has 256 nodes. What is max number of hops to locate an item?
a)
8
b)
16
c)
256
d)
4
15.
Which scheduling algorithm is ideal for hard real-time systems?
a)
First Come First Serve
b)
Round Robin
c)
Rate Monotonic Scheduling
d)
Shortest Job Next
16.
A hand-held system uses a display with a refresh rate of 60 Hz. If each refresh requires 5 ms of CPU time, what percentage of CPU time is consumed by the display?
a)
0.3
b)
0.2
c)
0.15
d)
0.1
17.
Why is memory management important in operating systems?
a)
To store large files
b)
To track processor usage
c)
To allocate memory space efficiently to processes
d)
To connect with the printer
18.
Which of the following statements is TRUE regarding Rate Monotonic Scheduling (RMS)?
a)
RMS assigns higher priority to tasks with longer periods.
b)
RMS ensures 100% CPU utilization.
c)
RMS is optimal for preemptive, fixed-priority scheduling.
d)
RMS does not work for periodic tasks.
19.
A real-time system requires 4 periodic tasks. The utilization is 0.60. Will the tasks be schedulable under RMS?
a)
No, because utilization exceeds 0.55
b)
Yes, because 0.60 < 0.7568
c)
No, RMS only supports 3 tasks
d)
Yes, all tasks are schedulable regardless of utilization
20.
Which of the following OS structures allows maximum modularity and security but has performance overhead due to communication?
a)
Monolithic kernel
b)
Microkernel
c)
Layered OS
d)
Virtual Machine OS
21.
In an embedded real-time system, what kind of memory allocation is preferred?
a)
Dynamic memory allocation
b)
Stack-based memory
c)
Garbage-collected memory
d)
Static memory allocation
22.
Interrupt occurs every 10 ms; handler takes 2 ms. What is max interrupt frequency without overlap?
a)
100 Hz
b)
500 Hz
c)
333 Hz
d)
1000 Hz
23.
A real-time task’s WCET is 15 ms, period is 60 ms. What is CPU utilization?
a)
0.15
b)
0.25
c)
0.33
d)
0.5
24.
A display refreshes at 60 Hz, each refresh needs 5 ms CPU time. CPU time % used by display?
a)
0.3
b)
0.2
c)
0.15
d)
0.1
25.
Which OS service ensures a process can securely access a file?
a)
Process Mgmt
b)
File Mgmt
c)
Memory Mgmt
d)
Device Mgmt
26.
In RMS, T1: 40 ms period, 10 ms exec; T2: 60 ms, 15 ms exec. Is the set schedulable (RMS bound for n=2 is 0.828)?
a)
Yes
b)
No
c)
Only if T1 priority
d)
Only if T2 priority
27.
A handheld memory manager allocates 512 KB. App needs 600 KB. What happens?
a)
Runs normally
b)
Allocation fails
c)
Switches to VM
d)
Uses secondary storage
28.
Which OS component interacts with hardware to manage I/O?
a)
Process Scheduler
b)
Device Driver
c)
Memory Allocator
d)
File System
29.
Illustrate how interrupts improve CPU efficiency in device communication.
a)
Polls devices regularly
b)
Stops programs frequently
c)
Triggers OS routines
d)
Resets device state
30.
Clarify the use of status registers in CPU processing.
a)
Stores ALU results
b)
Tracks interrupt queue
c)
Indicates CPU mode and flags
d)
Controls memory mapping
31.
Point out the reason for using multi-core CPUs in OS architecture.
a)
Reduces RAM usage
b)
Parallel task execution
c)
Enables BIOS access
d)
Improves user interface
32.
Predict the impact of disabling interrupts on OS responsiveness.
a)
Faster context switching
b)
Device buffering improves
c)
OS cannot respond to hardware
d)
No change
33.
Identify the benefit of using I/O channels in system architecture.
a)
Lowers CPU cycle count
b)
Enhances memory paging
c)
Controls scheduling policy
d)
Uses user-mode interrupts
34.
Demonstrate how microprogrammed control units simplify CPU design.
a)
Uses variable latency
b)
Implements OS processes
c)
Encodes control signals
d)
Replaces all hardware
35.
Examine why context switching requires CPU state preservation.
a)
To recompile programs
b)
To reload disk sectors
c)
To resume execution correctly
d)
To clean buffer cache
36.
Choose the suitable memory type for BIOS storage.
a)
DRAM
b)
SRAM
c)
ROM
d)
Cache
37.
In batch systems, turnaround time is:
a)
Higher than interactive systems
b)
Lower than real-time systems
c)
Similar to multiprogramming
d)
Not measurable
38.
Which OS type offers immediate feedback to the user?
a)
Batch
b)
Time-sharing
c)
Real-time
d)
Interactive
39.
A batch system executes 20 jobs in 100 minutes. What is the average turnaround time?
a)
4 min
b)
5 min
c)
10 min
d)
20 min
40.
Spooling overlaps:
a)
I/O and computation
b)
CPU and memory
c)
Cache and RAM
d)
Processes and threads
41.
What is the key benefit of multiprogramming?
a)
Maximizing I/O usage
b)
Reducing memory
c)
Increasing CPU utilization
d)
Avoiding deadlocks
42.
In a batch system, if each job takes 2 minutes of CPU and 8 minutes of I/O, what is the CPU utilization for a single job?
a)
0.2
b)
0.25
c)
0.8
d)
0.4
43.
A mainframe handles 1000 transactions/sec and supports 50 users. What is the average transactions per user per sec?
a)
20
b)
25
c)
15
d)
30
44.
A system with 10 servers processes 1000 requests/sec total. If load is equally balanced, how many requests per server?
a)
100
b)
1000
c)
10
d)
50
45.
A distributed system uses vector clocks with 8 processes. What is minimum size of vector clock?
a)
8
b)
1
c)
4
d)
16
46.
If network bandwidth is 1 Gbps and file size to transfer is 100 MB, how long will transfer take ignoring overhead?
a)
0.8 seconds
b)
0.1 seconds
c)
1.2 seconds
d)
0.4 seconds
47.
A distributed database replication lag is 200 ms. If writes per second are 500, what is max stale data duration?
a)
0.4 seconds
b)
0.2 seconds
c)
1 second
d)
2 seconds
48.
For a quorum system with N=15 nodes, write quorum size is 10, read quorum size is 6. Is the system consistent?
a)
Yes
b)
No
c)
Depends
d)
Cannot tell
49.
A distributed consensus protocol requires 2/3 of nodes to agree. For 30 nodes, what is minimum number of nodes required?
a)
20
b)
10
c)
15
d)
25
50.
A cluster has 5 nodes, each with 8 cores running at 2.5 GHz. What is total processing capacity in GHz?
a)
100 GHz
b)
40 GHz
c)
10 GHz
d)
50 GHz
100 %
