OS

Question 1

What is OS and its functions

Answer 1

Interface between user and hardware of a system
Functions:
controls computer processes
performs imp tasks
valuable service to user
handles/controls resources
hides complexity of s/w

Question 2

Memory management

Answer 2

OS handles primary memory of main memory
main memory divided in bytes or arrays…
OS allocates and deallocates address to processes
handles importance of processes

Question 3

Protection

Answer 3

mechanism which controls access of users, processes or programmers to resources provided by computer
In mutliprogramming, it allows safe sharing of files/directory

Question 4

Security

Answer 4

safety from unauthorized access
protection from hackers and viruses
firewall, antivirus

Question 5

Privacy

Answer 5

Keep essential information hidden and private

Question 6

Name at least three open-source operating systems.

Answer 6

1) Linux - Linus Torvalds (1991)
2) Android - Android has historically been developed by a consortium of developers known as the Open Handset Alliance, but its most widely used version is primarily developed by Google.
3) Chromium OS - It uses a web engine for the user interface.

Question 7

What are the key responsibilities of memory management in an OS?

Answer 7

1) Memory allocation
2) Memory deallocation
3) Memory protection
4) Paging and segmentation
5) Caching and compression

Question 8

Identify the primary functions of process management in an operating system.

Answer 8

Process Creation
Process resource management
Process Scheduling
Process sychronization
Process Termination

Question 9

Illustrate how file systems are organized in an operating system

Answer 9

Root directory
Directory
Subdirectory
Files
Files names

Question 10

Assess the advantages and disadvantages of modern operating systems compared to older systems.

Answer 10

adv :
improved security, inc perform., enhanced user experience, better h/w support, better network and connectivity
dis :
Complexity(steep learning curve), dependence on internet, cost of licensing, compatibility issues

Question 11

Paging and segmentation

Answer 11

Paging - dividing memory into pages/fixed - size blocks (equal sections)
Segmentation - dividing memory into variable - size segments

Question 12

Process Management

Answer 12

OS mechanism to manage a process from creation to termination

Question 13

Process Description and its contents

Answer 13

(PCB) Contains information related to the process.
Contents :
1 Process ID
2 Process State
3 Process Counter (address of the enxt process)
4 Register
5 Memory pointer
6 Memory Segment (segmented task various memory)
7 Open files
8 Signal (signal received by the processes)
9 Scheduling information
10 Accounting information

Question 14

Process Control

Answer 14

mechanism and techniques used by OS to manage and regulate the execution of a program
Stack (Temporary data)
Heap (Dynamic alloc mem)
Data (Global and static var)
Text (Current activity according to counter value and register contents)

Question 15

Evolution of OS

Answer 15

1940 - 1950
manual process handling, ENIAC, UNIVAC (no manual intervention, batch processing) (1940s)
1960
Multiprogramming and time sharing (CTSS) (multiple users into the same computer, using terminals)
1970
Unix launched (1971) and First microprocessor (Intel 4004) (1971)
1980
GUI and networking
Macintosh (1984), Microsoft (1985)
1990
Linux
advanced GUI
2000
Apple released Iphone (2007) and Android (2008)
Cloud based

Question 16

Multiprocessing | multitasking

Answer 16

1 executing multiple processes concurrently by use of multiple processors , by using same physical resources
2 multiple proce. , same physical resources
3 infrequent context switching, frequent
4 high scalability, low
5 uses batch os, uses time sharing
6 simultaneous processing, switches bet processes

Question 17

Schedulers

Answer 17

1 Long-Term Scheduler (Job Scheduler):
Responsible for selecting processes from the job pool and loading them into memory for execution.
Decides which processes to admit to the system and when.
2 Short-Term Scheduler (CPU Scheduler):
Responsible for selecting the next process to execute on the CPU.
Decides which process to execute next and for how long.
3 Medium-Term Scheduler:
Responsible for swapping processes in and out of memory to free up resources.

Question 18

Threads and types

Answer 18

Lightweight processes
User-level
managed by application, fast and lightweight, kernel unaware, limited control
Kernel-level
operating system manages, kernel schedules and manages, heavier but more control
Hybrid
combination