Page 241 - DCAP103_Principle of operating system

Principles of Operating Systems

Notes True or False:
8. Direct access does not allow a user to partitioned the read/write mark before reading or
writing.
9. A disk is typically position also known as slices and minidisks.

6.13 Summary

• A file is a collection of related information defined by its creator.
• Computer can store files on the disk (secondary storage), which provide long term storage.
A file can be managed in operating systems in three ways; from within a program, by
using MY computer, and by using Windows Explorer. A file is an abstract data type, a
“thing”, which is defined and implemented by the operating system.

• The main task of the operating system is to map the logical file concept onto physical
storage devices, such as disks or tapes. A file can be accessed directly or sequentially.
• A disk is typically partitioned, also known as slices and minidisks.

• The device directory or volume table of contents records and maintains the file properties
such as name, size, type and location.

• WebSphere Portal and the directories used for storing locale-specific resources is also been
explained.
• File sharing is also a very desirable for users who want to collaborate and to reduce the
effort required to achieve a computing goal. Therefore, user oriented operating systems
must accommodate the need to share files in spite of the inherent difficulties.
• Consistency semantics is an important criterion for evaluating any file system that supports
file sharing. It is a characterization of the system that specifies the semantics of multiple
users accessing a shared file simultaneously. Allocation methods are also a required feature
for file management.

6.14 Keywords

Domain Name System (DNS): A system for converting host names and domain names into
IP addresses on the Internet or on local networks that use the TCP/IP protocol. For example,
when a Web site address is given to the DNS either by typing a URL in a browser or behind
the scenes from one application to another, DNS servers return the IP address of the server
associated with that name.
Network Information Service (NIS): A naming service from Sun that allows resources to be
easily added, deleted or relocated. Formerly known as Yellow Pages, NIS is a de facto Unix
standard. NIS+ is a redesigned NIS for Solaris 2.0 products. The combination of TCP/IP, NFS
and NIS comprises the primary networking components of Unix.
Distributed File System (DFS): Is a set of client and server services that allow an organization
using Microsoft Windows servers to organize many distributed SMB file shares into a distributed
file system. DFS provides location transparency and redundancy to improve data availability in
the face of failure or heavy load by allowing shares in multiple different locations to be logically
grouped under one folder, or DFS root.

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