Lecture 1

Question 1

What is an OS?

Answer 1

The chief computer software that manages hardware and other software. It is a resource allocator and control program.

Question 2

Describe Serial Processing

Answer 2

Programmers used Machine language. Was very time confusing

Question 3

What are the three main objectives in OS Management?

Answer 3

1. Resource Efficiency
2. Convenience
3. Ability to adapt

Question 4

Explain the primary purpose of having an OS change from the 1960’s to 1990’s.

Answer 4

The transistion was mainly due to making the process cheaper and more convenient.

Question 5

Describe Batch Processing

Answer 5

Data is collected and executed together as a group, usually without immediate user interaction. It is commonly used to process large volumes of data in a more efficient and systematic manner.

Question 6

What is the difference between Multiprogramming and Multi processing?

Answer 6

Multiprogramming: The management of multiple processes within a uniprocessor system

Multiprocessing : The management of multiple processes within a multiprocessor

Question 7

Describe hyper-threading.

Answer 7

Hyper-threading is a hardware-level technology that allows a single physical core to function as two logical cores

Question 8

Describe multi threading

Answer 8

multi-threading is a software-level approach that involves running multiple threads within a single process

Question 9

Name three ways in which the processor can transition from user mode to kernel mode.

Answer 9

1. System Calls
   2.Exceptions/Interrupts/Page faults
2. Hardware Instructions

Question 10

How are multiple interrupts dealt with?

Answer 10

1. Disable interrupts
   while an interrupt is being processed.
2. Define priorities for interrupts and to allow
   an interrupt of higher priority to cause a lower-priority interrupt handler to be interrupted.

Question 11

How does the distinction between user-mode and kernel-mode provide a rudimentary form of
protection for your system?

Answer 11

Certain instructions could be executed only when the CPU is in kernel mode. Similarly, hardware devices could be accessed only when the program is executing in kernel mode.

Control over when interrupts should be enabled or disabled is also possible only when the CPU is in kernel mode.

The CPU has very limited capability when executing in user mode, thereby enforcing protection of critical resources.

Question 12

What is Time sharing?

Answer 12

A computing technique that allows multiple users or processes to share a single computer or its resources concurrently.

Question 13

List the evolution of OS from earliest to latest

Answer 13

1. Serial Processing
2. Simple Batch Processing
3. Multiprogrammed batch jobs
4. Time Sharing Systems
5. Real Tikme Systems
6. Distributed Systems