Interview Questions on OS - Basics

1. What is an Operating System?

An operating system is set of programs that acts as an interface between the user and the hardware

2. What is Clustered System?

Clustered computers share the storage and are linked via a local-area network (LAN). Clustering is usually used to provide high-availability service.(even if one fails another one will manage the storage)

3. What is Dual Mode Operation?

In order to ensure the proper execution of the operating system, we must be able to distinguish between the execution of OS code and user code. we need two separate modes of operation:
1. user mode.
2. kernel mode.

4. What is Timer?

We must prevent a user program from getting stuck in an infinite loop. To accomplish this goal, we can use a timer.

5. What is cache?

Information is normally kept in some storage system . When it is used, it is copied into a faster storage system called the cache. When we need a particular piece of information, we first check whether it is in the cache. If it is, we use the information directly from the cache; if it is not,we use the information from the source, putting a copy in the cache under the assumption that we will need it again soon.

6. What is System Call?

System calls are routines to perform a particular operation and provides interface to the services. These calls are generally written in C and C++ .

7. What is kernel?

Kernel is the core of the operating system which acts as an interface between hardware and software.