1. List out the different roles taken by the OS.
- Resource sharing
- Data security
- Data confidentiality
- Help facility
- Time sharing
- Job scheduling
- Multiprogramming
2. What are the desirable characters of the OS?
- User interface
- Memory management
- Process management
- File management
- Networking capabilities management
- Security management
- Fault tolerance
- Application base
- Distributed operating system
3. What are the types of Operating system?
As per the number of users, there are two types of operating systems. They are
- Single user Operating System
- Multi user Operating system
Single user operating system
At a time, only one user can operate the system. Eg: MS Disk Operating system
Multi user Operating system
More than one user can operate the same system simultaneously.
It is based on the concepts of time sharing.
Eg: Unix
4. Explain about Process management.
Process management undertakes the allocation of processors to one program. The operating system controls the jobs submitted to the system. Several algorithms are used to allocate the job to the processor.
- FIFO
- SJF
- Round Robin
- Based on Priority
5. Explain FIFO algorithm.
First In First Out (FIFO) is based on queuing. It is a little more technically. The process that enters the queue first is executed first by the CPU, then the next and so on. The processes are executed in the order in which they enter the queue.
6. Explain about SJF algorithm.
This algorithm is based on the size of the job.
Eg: Take two jobs A and B
A=5 kb
B=8 kb
Based on size of the job, A will be assigned processor time after which B gets its turn.
7. Explain Round Robin Algorithm.
Round-robin (RR) is one of the simplest scheduling algorithms for processes in an operating system. As the term is generally used, times are assigned to each process in equal portions and in circular order, handling all processes without priority. Round-robin scheduling is simple, easy to implement, and starvation-free. Round-robin scheduling can also be applied to other scheduling problems, such as data packet scheduling in computer networks. Here jobs are assigned processor time in a circular method.
8. Explain about security management.
The biggest challenge to the computer industry is safe guarding one’s data from unauthorized people. The Operating system provides three levels of securities to the user.
- File access level
- System Level
- Network Level
In order to access the files created by other people, you should have the requisite permission. Permission can either be granted by the creators of the file or by admin.
It is offered by the password in a multi user environment.
It is an elusive one. People from all over the world try to provide such security.
9. What is DOS?
A distributed operating system is the logical aggregation of operating system software over a collection of independent, networked, communicating, and physically separate computational nodes.
Individual nodes each hold a specific software subset of the global aggregate operating system. Each subset is a composite of two distinct services provisionary. The first is a ubiquitous minimal kernel, or microkernel, that directly controls that node’s hardware.
Second is a higher-level collection of system management components that coordinate the node's individual and collaborative activities. These components abstract microkernel functions and support user applications.
10. What is Fault tolerance?
Fault-tolerant describes a computer system or component designed so that, in the event that a component fails, a backup component or procedure can immediately take its place with no loss of service. Fault tolerance can be provided with software, or embedded in hardware, or provided by some combination.
Operating system should be robust. When there is a fault, the OS should not crash, instead the OS have fault tolerance capabilities
11. Write the objectives of the CPU Scheduling?
- The CPU utilization.
- The number of jobs done in a unit time and to minimize the time taken.
12. What are the goals achieved by Operating System?
- Execute user program in a user friendly atmosphere.
- Take the computer system convenient to use.
- Optimize computer hardware.
13. Write short note on user interface.
The operating system should concentrate on the user interface. The only way to user can interact with the computer is through the user interface.
The following points should also be considered when user interface is designed.
- The speed of response should play the vital role in designing the user interface.
- It should reduce the number of errors committed by the user.
- It should be pleasing to the senses.
- It should enable the people to retain this expertise for a long time.
14. What is operating system?
An operating system (OS) is a collection of software that manages hardware resources and provides common services for computer programs. The operating system is a vital component of the system software in a computer system. Application programs require an operating system to function.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting for cost allocation of processor time, mass storage, printing, and other resources.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware.
