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Monday, January 30, 2012
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2012
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operating system
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Operating system is a software program which runs on your PC or computer, it enables computer hardware to work or operate with computer software.Operating System can be classified into multi-user, multi tasking and real time software.
Operating Systems provide a platform where all other programs (Applications) can run. As we know operating system of different types. GUI, Multi user and DOS command are few. Here are FAQ in interview for freshers.
OPERATING SYSTEM INTERVIEW QUESTIONS AND ANSWERS
(Q) What is kernel?
(A) Kernel is the core and essential part of computer operating system that provides basic services for all parts of OS.
(Q) What is difference between micro kernel and macro kernel?
(A) Micro kernel is a kernel which run services those are minimal for operating system performance. In this kernel all other operations are performed by processor.
Macro Kernel is a combination of micro and monolithic kernel. In monolithic kernel all operating system code is in single executable image.
(Q) Difference between multi tasking, multi programming and multi threading?
(A) Multi programming – By the name itself it shows that it is a technique of running several programs at same time using time sharing.
Multi tasking – It is a logical name for multi programming. Difference is the user can switch between two tasks while the program is in running state.
Multi threading – An application is generally implemented as separate process with several threads. Different application has different threads, one thread will be in wait state till other thread completes.
(Q) What is dead lock?
(A) Deadlock is a situation or condition where the two processes are waiting for each other to complete so that they can start. This result both the processes to hang.
(Q) What are the methods of handling dead locks?
(A) Ensure that the system will not enter deadlock.
Recover the dead lock if it occurs.
See that no other process has to wait for other process to complete for longer time.
(Q) What is logical and physical addresses space?
(A) Logical address space is generated from CPU; it bound to a separate physical address space is central to proper memory management. Physical address space is seen by the memory unit. Logical address space is virtual address space. Both these address space will be same at compile time but differ at execution time.
(Q) What is starvation and aging?
(A) Starvation is Resource management problem where a process does not get the resources it needs for a long time because the resources are being allocated to other processes.
(Q) Which command is used to duplicate the entire diskette?
(A) While using DOS on PC diskcopy command is used.
(Q) What is virtual memory?
(A) Virtual memory is a technique which helps to get more memory than actual system memory; this is done using time sharing.
(Q) What is semaphore?
(A) Semaphore is a variable whose status reports common resource, semaphore is of two types one is Binary semaphore and other is Counting semaphore.
(Q) What is difference between binary semaphore and mutex?
(A) Mutex is used exclusively for mutual exclusion. Both mutual exclusion and synchronization can be used by binary. Mutex is given only through the task which takes mutex. Options for making the task which takes as DELETE_SAFE are provided by Mutex, which means the task deletion is not possible when holding the mutex.
(Q) What is the state of processor when a processor is waiting for some event to occur?
(A) Waiting state
(Q) What is fragmentation? Tell about different types of fragmentation?
(A) When many of free blocks are too small to satisfy any request then fragmentation occurs. External fragmentation and internal fragmentation are two types of fragmentation. External Fragmentation happens when a dynamic memory allocation algorithm allocates some memory and a small piece is left over that cannot be effectively used. Internal fragmentation is the space wasted inside of allocated memory blocks because of restriction on the allowed sizes of allocated blocks.
(Q) What is DRAM?
(A) DRAM is cheap, it`s data resides in a cell made of a capacitor and a transistor. The capacitor tends to lose data unless it’s recharged every couple of milliseconds, and this recharging tends to slow down the performance of DRAM compared to speedier RAM types.
