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31. At What Mode The Fault Handler Executes?
Date Posted: 07/02/2012
Ans: At the Kernel Mode.
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32. What Are States That The Page Can Be In, After Causing A Page Fault?
Date Posted: 07/02/2012
Ans:
- On a swap device and not in memory,
- On the free page list in the main memory,
- In an executable file,
- Marked “demand zero”,
- Marked “demand fill”.
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33. What Is Major Difference Between The Historic Unix And The New BSD Release Of Unix System V In Terms Of Memory Management?
Date Posted: 07/02/2012
Ans: Historic UNIX uses Swapping – entire process is transferred to the main memory from the swap device, whereas the Unix System V uses Demand Paging – only the part of the process is moved to the main memory. Historic UNIX uses one Swap Device and Unix System V allow multiple Swap Devices.
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34. How Do You Execute One Program From Within Another?
Date Posted: 07/02/2012
Ans: The system calls used for low-level process creation are execlp () and execvp (). The execlp call overlays the existing program with the new one, runs that and exits. The original program gets back control only when an error occurs.
Execlp (path, file_name, arguments); //last argument must be NULL
A variant of execlp called execvp is used when the number of arguments is not known in advance.
Execvp (path, argument_array); //argument array should be terminated by NULL
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35. What Is Single Users System?
Date Posted: 07/02/2012
Ans: The personal computer (PC) is a small, general-purpose system that can execute programs to perform a wide variety of tasks. The PC, however, was designed for use by one person at a time; that is, it is Single-User oriented with MS-DOS as the de facto standard operating system for this range of machines. Single user systems became very popular due to the low cost hardware and wide range of software available for these machines.
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36. What Is The Use Of Break And Continue Statements?
Date Posted: 07/02/2012
Ans: The continue statement suspends execution of all statements following it, and switches control to the top of the loop for the next iteration. The break statement, on the other hand, causes control to break out of the loop.
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37. What Are The Features And Benefits Of UNIX?
Date Posted: 07/02/2012
Ans:
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Portability
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Machine Independent
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Multi-user operations
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Hierarchical file system
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Unix shell
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Pipes and filters
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Utilities
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Background Processing
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Software Development Tools
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Maturity
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38. What Is The Command To Send Message To All Users Who Are Logged In?
Date Posted: 07/02/2012
Ans: Wall
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39. What Does The Top Command Display?
Date Posted: 07/02/2012
Ans: Top command displays the current amount of memory occupied by the currently executing processes and the details. In addition to memory usage top command displays cpu usage and process details.
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40. What Are PIDs?
Date Posted: 07/02/2012
Ans: They are process IDs given to processes. A PID can vary from 0 to 65535.
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