install fedora

Install fedora
1.change bios system  If you are using a live USB, you might need to go into your BIOS and change the boot priority in order to boot from your USB. You can access your computer's BIOS by pressing ‘F2’ or ‘Delete’ on most computers when the computer is booting up. If you are using a CD or DVD, ignore this step as generally CDs are first in boot priority.
2. Be sure to select "Live Drive" when the option screen first appears. If you select to install it, it can potentially delete everything from your system.
3.Explore the system. The most notable thing about you should toy with is the window manager which allows you to see pretty cool effects. You should also explore around the applications already installed in the OS and see what else is available with their package manager.

4. Install the live image to your hard drive .If you have made the decision to install Linux on your system, click on the "Install to Hard drive" icon on the workspace.
5.Click on next when the installer starts and then select your keyboard layout.

6.Choose the host name. It can be left as is or you can enter in the name you desire. That is going to be the name for the computer. Then click on next.

7.Choose the mode of installation. You could:

• Use entire drive. As the title says, Fedora would clear off all the data on your hard drive and use the complete space for its installation. But beware that you could lose all data on your drive .
• Use free space. If you have unallotted space on your hard drive, all that space is used for Fedora installation .
• Replace existing Linux System. If you are sure that you are running another Linux distribution and are quite keen to remove it, use this option and click next.
• Shrink current system. This option allows you to shrink any of the partitions so as to install Fedora.
• Create Custom Layout. Allows you to create and delete partitions manually.(Experienced users only.)

8.Choose one which suits you the most and click next. Confirm by clicking on ‘write changes to disk’.

 9.Wait for it to complete the install . After this installation starts, it will take approximately take 5-10 minutes (depending on your system) for it to be complete .

10.Re-boot the computer when the installation is done. Go to System > Shut Down and make sure to remove your live CD from the CD drive or your USB drive from the USB port.

11.Click on ‘forward’ on the first boot wizard and read and accept the license agreement.

12.Click on forward again. At the Create User prompt, enter the user name you desire, your full name, and your password.
13.set your date and time, then click on the ‘Network Time Protocol’ tab. With the network time protocol (NTP), your computer can fetch the current time from a time server over the internet, so you do not have to adjust the time every time DST goes into or out of effect. Select enable network time protocol and click ‘forward’.
14. Optional: Send details about your hardware to the Fedora Project to further help them develop the software according to hardware specifications.
15.Log-in and enter your password and you can now call yourself a Fedora user. This is how your Fedora desktop will look.

Input Output Management

Input Output Management

·        Managing input & output in Windows XP involves many operating system components.

·        User-mode processes interact with an environment subsystem and not directly with kernel-mode components.

·        The environment subsystem pass input & output request to the input & output manager, which interacts with devices drivers to handle such request.

·         Several device drivers, organized into a driver stack, cooperate to fulfill an input & output request.

·        The plug and play manager dynamically recognizes when new devices are added to the system and allocates and deallocates  resources, such as input & output ports or DMA channels, to them.

·        The power manger administers the operating system’s power management policy.

BUFFERING

·        Buffer overflow weakness is one of the many disadvantages of this type of security computer.

·        Buffer overflow attacks occur when the excessive Attacker provide input on the plan on the run.

·        Buffer overflow results from the weakness of the programming language c, c + +, fortran, and assembly, which does not automatically check the limit input when the program is executed.

·        The program is so complex, until programmers themselves do not know the weaknesses of the program.

·        Relies on external data to control the program.

·        Buffer is provided at the memory allocation, such as arrays or pointers in C. in the language C and C + +, there is no automatic restrictions on buffer, where users can write through the input buffer. For example:

int main () {

int buffer [10];

buffer [20] = 10;

}

·        Program in C above is a valid program, and each compiler to compile without error.

·        A process is a program in execution.

Spoiling Techniques

·        In computer science, spooling refers to a process of transferring data by placing it in a temporary working area where another program may access it for processing at a later point in time.

·        The normal English verb "spool" can refer to the action of a storage device that incorporates a physical spool or reel, such as a tape drive.

·        Spooling refers to copying files in parallel with other work.

·     The most common use is in reading files used by a job into or writing them from a   buffer on a magnetic tape or a disk.

·      Spooling is useful because devices access data at different rates. The buffer provides a waiting station where data can rest while the slower device catches up.

 FILE SYSTEM MANAGEMENT

Also referred to as simply a file system or file system.
  -The system that an operating system or program uses to organize and keep track of files.
-For example, a hierarchical file system is one that uses directories to organize files into a tree structure.
-Although the operating system provides its own file management system, you can buy separate file management systems.

 -These systems interact smoothly with the operating system but provide more features, such as improved backup procedures and stricter file protection.

File Sharing

  -Sharing of files on multi-user systems is desirable
  -Sharing may be done through a protection scheme
  -On distributed systems, files may be shared across a network
  -Network File System (NFS) is a common distributed file-sharing method

Directory Structure

- A collection of nodes containing information about all files.

-Both the directory structure and the files reside on disk.
 -Backups of these two structures are kept on tapes

File Mapping
- File mapping is the association of a file's contents with a portion of the virtual address space of a process.
- The system creates a file mapping object (also known as a section object) to maintain this association.
- A file view is the portion of virtual address space that a process uses to access the file's contents.
- File mapping allows the process to use both random input and output (I/O) and sequential I/O.
- It also allows the process to work efficiently with a large data file, such as a database, without having to map the whole file into memory.
- Multiple processes can also use memory-mapped files to share data.
- Processes read from and write to the file view using pointers, just as they would with dynamically allocated memory.
- The use of file mapping improves efficiency because the file resides on disk, but the file view resides in memory.
- Processes can also manipulate the file view with the Virtual Protect function.

protection and security consept

I.            protection and security concept.
security

Security software is available in many forms. For users who intend to surf the Internet, antivirus software is the basic software should be owned. This antivirus software will scan every file sent and received from the internet to check the probability of a virus. Two major antivirus software suppliers are Norton and McAfee. both the supplier has a good reputation in the international market. To remain effective, antivirus software should be updated often because many viruses are created every day. The virus enters the operating system when it successfully invades undetected.

protection

Addition of firewall system is a personal choice. This system will provide another layer of added protection when users on the Internet. Each program must obtain permission from the firewall to the computer to send and receive any information that comes from the Internet. Computer firewall can be modified, allowing users to allow any program that they can trust. For programs that do not know the origin, Firewall will block any action by any of these programs to seek permission from the user.

protection and security concept.

Protection concepts
The aim of the concept of computer virus protection is to create suitable safeguards with which the occurrence of computer viruses in the IT systems of an organisation can be prevented or detected as early as possible. In this way, countermeasures can be taken and possible damage can be minimised. In the protection against computer viruses it is essential that the safeguards are consistently adhered to and that technical countermeasures are constantly updated. This requirement is due to the continual occurrence of new computer viruses or variants of viruses. The development of operating systems, programming languages and application software may also provide opportunities for computer viruses to attack. This should therefore be taken into account and suitable countermeasures should be taken.



Security concepts
Certain concepts recur throughout different fields of security:
Assurance - assurance is the level of guarantee that a security system will behave as expected
Countermeasure - a countermeasure is a way to stop a threat from triggering a risk event
Defense in depth - never rely on one single security measure alone
Exploit - a vulnerability that has been triggered by a threat - a risk of 1.0 (100%)
Risk - a risk is a possible event which could cause a loss
Threat - a threat is a method of triggering a risk event that is dangerous
Vulnerability - a weakness in a target that can potentially be exploited by a threat security


Recognize security policy and mechanism.
Protection mechanisms

In computer science, protection mechanisms are built into a computer architecture to support the enforcement of security policies. A simple definition of a security policy is "to set who may use what information in a computer system.

- a mechannism for controlling the access of programs, processes, or users the resources defined by the computer system.

- the protention mechanism ensures the enforcement of a certain policy.

- policy is established in several ways:

i. system design.

ii. system management.

 iii user defined.



Security in computer system

- security is an enternal operating systems problem-providing controlled access to programs and data stored in the computer
- security is mainly focused on malicious behavior of entities external to the system,affecting computer assets:

i. software

      ii. data
      iii.Hardware

Memory management

Memory management

Memory management is the act of managing computer memory. In its simpler forms, this involves providing ways to allocate portions of memory to programs at their request, and freeing it for reuse when no longer needed. The management of main memory is critical to the computer system.

Virtual memory systems separate the memory addresses used by a process from actual physical addresses, allowing separation of processes and increasing the effectively available amount of RAM using disk swapping. The quality of the virtual memory manager can have a big impact on overall system performance.


Memory management systems on multi-tasking operating systems usually deal with the following issues.

ProtectionMain article: Memory protection
Processes should not be able to reference the memory for another process without permission. This is called memory protection, and prevents malicious or malfunctioning code in one program from interfering with the operation of other running programs.

SharingMain article: Shared memory
Even though the memory for different processes is normally protected from each other, different processes sometimes need to be able to share information and therefore access the same part of memory. Shared memory is one of the fastest techniques for Inter-process communication.

Logical organizationPrograms
are often organized in modules. Some of these modules could be shared between different programs, some are read only and some contain data that can be modified. The memory management is responsible for handling this logical organization that is different from the physical linear address space. One way to arrange this organization is segmentation.

Physical OrganizationMemory
is usually divided into fast primary storage and slow secondary storage. Memory management in the operating system handles moving information between these two levels of memory.