1.Write down the storage device hierarchy with its diagram.
- Secondary Storage is used as an extension of main memory. Secondary storage devices can hold the data permanently.
- Storage devices consists of Registers, Cache, Main-Memory, Electronic-Disk, Magnetic-Disk, Optical-Disk, Magnetic-Tapes.
2.What is virtual machine?
- A virtual machine (VM) is a virtual environment that functions as a virtual computer system with its own CPU, memory, network interface, and storage, created on a physical hardware system (located off- or on-premises).
3.Write the difference between job and process scheduler.
- Process scheduling (or management) normally refers part of the operating system that shares CPU resources among the currently running programs (also called processes). ... Job scheduling typically refers to programs that are to be run at a set time, typically (but not always) on a repetitive basis.
4.When does deadlock situation arise?
- A deadlock situation on a resource can arise if and only if all of the following conditions hold simultaneously in a system: Mutual exclusion: At least one resource must be held in a non-shareable mode. Otherwise, the processes would not be prevented from using the resource when necessary.
5.Define: Monitor.
- The monitor is one of the ways to achieve Process synchronization. The monitor is supported by programming languages to achieve mutual exclusion between processes.
6.What is overlay?
- Overlaying means "the process of transferring a block of program code or other data into internal memory, replacing what is already stored". Overlaying is a technique that allows programs to be larger than the computer's main memory.
7.Write down the differences between paging and segmentation scheme.
- In Paging, a process address space is broken into fixed sized blocks called pages. In Segmentation, a process address space is broken in varying sized blocks called sections. Operating System divides the memory into pages. ... During segmentation, a logical address is divided into section number and section offset.
8.What is virtual memory?
- Virtual memory is a feature of an operating system that enables a computer to be able to compensate shortages of physical memory by transferring pages of data from random access memory to disk storage. This process is done temporarily and is designed to work as a combination of RAM and space on the hard disk.
9.Define: Thrashing.
- Thrashing is a condition or a situation when the system is spending a major portion of its time in servicing the page faults, but the actual processing done is very negligible. The basic concept involved is that if a process is allocated too few frames, then there will be too many and too frequent page faults.
10.What are file attributes?
- File attributes are settings associated with computer files that grant or deny certain rights to how a user or the operating system can access that file.
11.What is an Interface?
- In computing, an interface is a shared boundary across which two or more separate components of computer system exchange information. The exchange can be between software, computer hardware, peripheral devices, humans, and combinations of these.
12.What is Encryption?
- Encryption is the process of taking plain text, like a text message or email, and scrambling it into an unreadable format — called “cipher text.”
13. Define operating system.
- An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
14. What is a process?
- Process is the instance of a computer program that is being executed by one or many threads. It contains the program code and its activity. Depending on the operating system (OS), a process may be made up of multiple threads of execution that execute instructions concurrently.
15. What are the types of management present in operating system?
- Process management.
- Memory management.
- File and disk management.
- I/O system management
16.What is semaphore?
- Semaphore is simply a variable that is non-negative and shared between threads. A semaphore is a signaling mechanism, and a thread that is waiting on a semaphore can be signaled by another thread. It uses two atomic operations, 1) wait, and 2) signal for the process synchronization.
17.What is monitor? Draw the diagrammatic view of a monitor.
- In concurrent programming (also known as parallel programming), a monitor is a synchronization construct that allows threads to have both mutual exclusion and the ability to wait (block) for a certain condition to become false. ... A monitor consists of a mutex (lock) object and condition variables.
18.What is dynamic loading?
- Dynamic loading is a mechanism by which a computer program can, at run time, load a library (or other binary) into memory, retrieve the addresses of functions and variables contained in the library, execute those functions or access those variables, and unload the library from memory.
19.What are the problems occurred due to fragmentation?
- The most severe problem caused by fragmentation is causing a process or system to fail, due to premature resource exhaustion: if a contiguous block must be stored and cannot be stored, failure occurs. Fragmentation causes this to occur even if there is enough of the resource, but not a contiguous amount.
20.What is the use of paging scheme?
- In computer operating systems, paging is a memory management scheme by which a computer stores and retrieves data from secondary storage for use in main memory. In this scheme, the operating system retrieves data from secondary storage in same-size blocks called pages.
21.List down the types of access methods.
- Sequential Access – It is the simplest access method. Information in the file is processed in order, one record after the other.
- Direct Access – Another method is direct access method also known as relative access method. A filed-length logical record that allows the program to read and write record rapidly in no particular order.
- Index sequential method –It is the other method of accessing a file which is built on the top of the sequential access method.
22. What is a file?
- A file is a named collection of related information that is recorded on secondary storage such as magnetic disks, magnetic tapes and optical disks
23.Write down the examples for peripheral device.
- Peripheral devices can be external or internal.
- Examples of external peripherals include mouse, keyboard, printer, monitor, external Zip drive or scanner.
- Examples of internal peripherals include CD-ROM drive, CD-R drive or internal modem.
24. How can we give authentication? Explain.
- Authentication is the process of recognizing a user's identity. The credentials provided are compared to those on a file in a database of the authorized user's information on a local operating system or within an authentication server
25.What is an operating system?
- An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
26.Define Kernel.
- A Kernel is a computer program that is the heart and core of an Operating System. Since the Operating System has control over the system so, the Kernel also has control over everything in the system. It is the most important part of an Operating System.
27.List any Three OS Components.
Major components of an OS are
- file system
- scheduler
- and device driver.
28.List the various process states.
- New.
- Ready.
- Ready Suspended.
- Running.
- Blocked.
- Blocked Suspended.
- Terminated.
29.What is meant by context switch?
- Context switch is the process of storing the state of a process or thread, so that it can be restored and resume execution at a later point. This allows multiple processes to share a single central processing unit (CPU), and is an essential feature of a multitasking operating system.
30.Define Deadlock.
- Deadlock occurs when a process or thread enters a waiting state because a requested system resource is held by another waiting process, which in turn is waiting for another resource held by another waiting process.
31.What do you mean by best fit?
- The best fit deals with allocating the smallest free partition which meets the requirement of the requesting process. It then tries to find a hole which is close to actual process size needed.
32.Define swapping.
- Swapping is mechanisms in which a process can be swapped temporarily out of main memory (or move) to secondary storage (disk) and make that memory available to other processes.
33.Define Demand Paging.
- Demand paging is a method of virtual memory management. It follows that a process begins execution with none of its pages in physical memory, and many page faults will occur until most of a process's working set of pages are located in physical memory.
34.What is Virtual Memory?
- A computer can address more memory than the amount physically installed on the system. This extra memory is actually called virtual memory and it is a section of a hard disk that's set up to emulate the computer's RAM.
35.What do you mean by Access Right?
- Access Rights are the permissions an individual user or a computer application holds to read, write, modify, delete or otherwise access a computer file; change configurations or settings, or add or remove applications
36.What you mean by a Layered Approach?
- This approach breaks up the operating system into different layers. This allows implementers to change the inner workings, and increases modularity.
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