CS1005 UNIX Internals B.E Question Bank : sriengg.com
Name of the College : Srinivasan Engineering College
University : Anna University
Department : Computer Science & Engineering
Degree : B.E
Subject Code/Name : CS1005 UNIX Internals
Year : 4th
Semester : 7th
Document Type : Question Bank
Website : sriengg.com
Download Model/Sample Question Paper :https://www.pdfquestion.in/uploads/sriengg.com/3231-Unix-internal-2marks-16marks.pdf
Srinivasan UNIX Internals Question Paper
UNIX Internals :
Unit – I
1. Define shell :
A shell is a program that provides the traditional, text-only user interface for Linux and other Unix-like operating systems. Its primary function is to read commands that are typed into a console.
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2. Mention the properties of UNIX OS :
** It has a simple user interface that has the power to provide the services that users want.
** It provides primitives that permit complex programs to be built from simpler programs.
** It uses a hierarchical file system that allows easy maintenance and efficient implementation.
** It uses a consistent format for files, the byte stream, making application programs easier to write.
** It provides a simple, consistent interface to peripheral devices.
** It is a multi-user, multiprocess system; each user can execute several processes simultaneously.
** It hides the machine architecture from the user, making it easier to write programs that run on different hardware implementations.
3. Mention the use of the fork System call :
The ‘fork()’ call is used to create a new process from an existing process. The new process is called the child process, and the existing process is called the parent. We can tell which is which by checking the return value from ‘fork()’
4. Mention the use of command “Passwd” :
The passwd command sets and changes passwords for users. Use this command to change your own password .
5. Define Exceptions :
An exception is a runtime error or warning condition, which can be predefined or user-defined. Predefined exceptions are raised implicitly (automatically) by the runtime system.
Unit – II
6. Define interrupt :
Interrupt is a signal sent or given to the processor in order to interrupt or to stop the current process/execution and transfer the control to the specified process in order to perform particular task.
7. List the building block primitives of UNIX with Examples :
Unix enables to write small modular program that can be used as building block to build more complex programs.
8. Define Swapping :
Swapping is a useful technique that enables a computer to execute programs and manipulate data files larger than main memory.
9. Define paging :
paging is one of the memory-management schemes by which a computer can store and retrieve data from secondary storage for use in main memory. In the paging memory-management scheme, the operating system retrieves data from secondary storage in same-size blocks called pages. The main advantage of paging over memory segmentation is that it allows the physical address space of a process to be noncontiguous.
10. Characterization of unix file system :
** Hierarchical structure
** Consistent treatment of file data.
** Ability to create and delete files.
** Dynamic growth of files.
Unit – III
11. Define user mode :
It is a non-privileged mode in which each process starts out. It is non-privileged in that it is forbidden for processes in this mode to access those portions of memory that have been allocated to the kernel or to other programs.
12. Define kernel mode :
When the CPU is in kernel mode, it is assumed to be executing trusted software, and thus it can execute any instructions and reference any memory addresses.
13. Define buffer :
A buffer is a region of a physical memory storage used to temporarily hold data while it is being moved from one place to another.
14. Define system call :
A system call is the mechanism used by an application program to request service from the operating system. Operating systems contain sets of routines for performing various low-level operations.
15. What are the important fields in u area :
** Pointer to the process table
** Parameters of the current system call
** File descriptors for all open file
** Internal I/O parameters
16. Define various lifetime of a process :
** The process is currently executing in user mode.
** The process is currently executing in kernel mode.
** The process is not executing, but it is ready to run as soon as the scheduler chooses it.
** The process is sleeping.
17. Define sleep :
Process are said to sleep on a event, meaning that they are in the sleep state until the event occurs.
18.Define the fields in process table :
** A process table.
** Identifiers indicating the user who owns the process.
** An event descriptor set when a process is suspended.