MY PROTECTION & SECURITY

MY PROTECTION & SECURITY

Security policy and mechanism

The term security and protection are often used interchangeable.

Nevertheless, it is frequently useful to make a distinction between the general

problems involved in making sure that files are not read or modified by

unauthorized persons, which include technical, managerial, legal and political

issues on the one hand, and the specific operating system mechanism used to

provide security on the other to avoid confusion, we will use the term security to

refer to the overall problem, and the term protection mechanisms to refer to the

specific operating system mechanisms used to safeguard information in the

computer. The boundary between them is not well defined

Some common categories are:

1. Casual prying by non technical users. Many people have terminals to

timesharing systems on their desks, and human nature being what it is, some of

them will read other people’s electronic mail and other files if no barriers are

placed in the way. Most UNIX systems, for example, have the default that all

files are publicly readable.

2.

Snooping by insiders. Student, systems programmers, operators, and other

technical personal often consider it to be a personal challenge to break the

security of the local computer system. They often are highly skilled and are

willing to devote a substantial amount of time to effort.

3.

Determined attempt to make money. Some bank programmers have attempted

to break into a banking system to steal from the bank. Scheme have varied from

changing the software to truncate rather than round interest, keeping the fraction

of a cent for themselves, to siphoning off accounts not used in years, to

blackmail

~FILE SYSTEM MANAGEMENT~

File system management objectives

A file management system is that set of system software that provides

services to users and applications related to the use of files.

include storage of data and the ability to perform the operations listed

earlier.

Concept and design

The operating system abstract from the physical

properties of its storage devices to define a logical storage unit, the file. File are

mapped, by the operating system, on to physical devices. This storage device are

usually non volatile, so the contents are persistent thru power failures and

systems reboots.

File directory

The directory is itself a file, owned

by the operating system and accessible by various to users and applications,

information is generally provided indirectly by system routines. Thus, users
cannot directly access the directory even in read-only mode

File Sharing 

Access Rights

The file systems provide a flexible tool for the following extensive file sharing

among users. The file system should provide a number of options so that the

way in which a particular file is accessed can be controlled.

To meet the data-management needs and requirements of the user, whichTo guarantee, the extent possible that the data in the file are valid

This relieves the user or programmer of the necessity of developing

special purpose software for each application and provide the system with a

means of controlling its most important asset.[GROS86] suggests the following

objectives for file management system: