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Unformatted text preview: ccess to the requested resource. The three
basic approaches to user authentication are proof by knowledge, proof by
possession, and proof by property.
37. Access control mechanisms are used to prohibit a user/process from accessing
those resources/information that he/she/it is not authorized to access.
Cryptography is a means of protecting private information against
unauthorized access in those situations where it is difficult to ensure access
control. The basic idea behind this security technique is that if it is not possible to
ensure access control, it is better to prevent comprehension of information. 39. The command interpretation module (known as command interpreter) of an
operating system serves as an interface for the user to communicate with the
computer via its operating system. The two broad categories of user interfaces
supported by various operating systems are command-line interface and graphical
40. The kernel of an operating system is its central controlling part that
implements the most primitive of the system's functions. It is the only part of an
operating system that a user cannot replace or modify.
41. Those modules of an operating system that are always kept in the system's
main memory are called resident modules and those that are kept on hard disk are
called non-resident modules. The non-resident modules are loaded into the
memory on demand, that is, as and when they are needed for execution.
42. A real-time system is a system that must satisfy the requirement of producing
the desired results before a certain deadline. Operating systems that are designed
to handle the processing requirements of real-time systems are called real-time
43. Computer systems consisting of interconnected, multiple computers are called
distributed computing systems.
44. The operating systems commonly used for distributed computing systems can
be broadly classified into two types - network operating systems and distributed
operating systems. In cas...
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This document was uploaded on 04/07/2014.
- Spring '14