Isnin, 21 Mac 2011

FORMAT PC USING WINDOWS OR LINUX

 Windows vista

Step 1. Insert your Windows Vista DVD. The DVD is bootable so after you restart your PC (with the DVD inside) the Windows Vista Setup will begin loading ( if the setup doesn’t start automatically, make another restart and press F2, or F8 after the boot screen and select boot from DVD ).


Step 2. The first screen of the Format Windows Vista sequence will show up. At this point you need to select your Language and Time and currency format (click the image to enlarge). Press Next.



Step 3. Press Install Now

Step 4. After a min you will be asked for your Product Key.
Scenario 1: If you don’t have your product key, you can skip this step and at the next step you will be asked to pick Vista Package that you want to install : Vista Home Basic, Home Premium, Business, Ultimate. If you install windows vista without providing product key, after 14 days you will have to enter a valid product key, or if you don’t, you’ll be forced to format windows vista again. This is good if you want to test which windows vista version is best for you, before your purchase.
Scenario 2: You enter your product key (keep it handy!), and at the next screen your purchased version will be auto-recognized.


Step 5. Accept the Microsoft Windows User License Terms and press Next


Step 6. Dialog – “Which type of installation do you want ?”
Scenario 1: If you already have another operating system installed (ex. Windows XP) you will have the Upgrade option enabled. It’s up to you to decide if you prefer “clean” install or upgrading from previous Windows Installation. Clean install is recommended for improving system performance, and Upgrade Setup is recommended if you have some files in your C: , My Documents, or Desktop folders that you don’t want deleted.
Scenario 2: You already have operating system installed but you want to format your drive, deleting the old system and installing fresh Windows Vista copy. In that case select the C: drive and press Format ( don’t format all drives! only the primary where we are installing Windows Vista – ” C: “. The setup will do the rest.


Step 7. Select Disk 0 and click Next


Step 8. The copy process will begin. This process can take some time, so relax a bit, make a coffee or something :D . Your input won’t be required here for some time.


Step 9. After Windows Vista Setup finishes, the computer will reboot.


Step 10. Windows Vista files are copied , and now setup will configure Windows Vista for your PC. This step will take some really good time.
Step 11. Installing Windows Vista finishes, insert your User Name and Password here.


Step 12. Give your PC a name! and select one of the colorful backgrounds


Step 13. Select your preferred security settings. If this computer is not behind a firewall, the best option is the ” Use Recommended settings”. If you are using firewall then you can select “Install important updates only” (Windows Update). If you want to be protected and your Windows Vista to have the latest updates from Microsoft , select the first option.


Step 14. Select your time zone and location.


Step 15. Network Configuration – Select your computer location. This settings sets your network permissions.


Step 16. This is self explanatory :) Welcome to your new Windows Vista Operating System


Step 17. After you press Start, some Windows Vista settings will be upgraded automatically.
Step 18. You now need to install some drivers that the system will not install automatically.
Finished.

















Khamis, 17 Mac 2011

SYSTEM PROTECTION AND SECURITY

Definition of policy in system security is “what is allowed and what is not allowed“. And the respective mechanisms enforces policies. There are three goals of security: to prevent attackers from violating security policies, to detect attackers who are violating security policies, and to recover which stops the violation and repairs damage. The last one also includes the ability to function after being attacked.

There are three types of mechanisms. Secure, Precise, and Broad states. In a secure state mechanism, we allow the reachable states to be within a subset of reachable state. Therefore we provide extra security in this mechanism. In a precise state, we allow reachable states to go to all the secured states. That is to say that a user is allowed to go to all secured state and the number of reachable and secured state is the same, in other words, precise. In a broad state, we allow the user to go to an unsecured state and then a set of secured state. This is the most vulnerable mechanism.

In order to ponder on these issues we take a lot of things into consideration. We should determine the cost benefit of if it is cheaper to recover or to prevent. We should also do a risk-analysisWe should also keep the law and customs in mind, we should know if certain security measures are within the law or not, or would people even use these security measures.

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.



INPUT AND OUTPUT MANAGEMENT

INPUT & OUTPUT MANAGEMENT

• Managing input & output in Windows XP involves many operating system componets.

• User-mode processes interact with an enviroment subsystem and not directly with kernel-mode componets.

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

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

• The plug and play manager dynamicaly 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 mangement policy.

• The power policy detemines whether to power down devices to conserve energy or keep them fully powered for high responsiveness.


Elaborate the concept of 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

• Buffee 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, sehinnga 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 buffernya, 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.

 Recognize spooling technique

• 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.

• This temporary working area would normally be a file or storage device.

• The most common spooling application is print spooling: documents formatted for printing are stored onto a buffer (usually an area on a disk) by a fast processor and retrieved and printed by a relatively slower printer at its own rate.

• Spooler or print management software may allow priorities to be assigned to jobs, notify users when they have printed, distribute jobs among several printers, allow stationery to be changed or select it automatically, generate banner pages to identify and separate print jobs, etc.

• The temporary storage area to which E-mail is delivered by a Mail Transfer Agent and in which it waits to be picked up by a Mail User Agent is sometimes called a mail spool


MEMORY MANAGEMENT CONCEPT

Relocatin policy
·         In systems with virtual memory, programs in memory must be able to reside in different parts of the memory at different times. This is because when the program is swapped back into memory after being swapped out for a while it can not always be placed in the same location. The virtual memory management unit must also deal with concurrency. Memory management in the operating system should therefore be able to relocate programs in memory and handle memory references and addresses in the code of the program so that they always point to the right location in memory.

Location of Outdoor System:
-         The allocator places a process in the smallest block of unallocated memory in which it will fit.

-         The memory manager places process in the largest block of unallocated memory available. The ides is that this placement will create the largest hole after the allocations, thus increasing the possibility that, compared to best fit, another process can use the hole created as a result of external fragmentation.



First Fit:
-         Another strategy is first fit, which simply scans the free list until a large enough hole is found. Despite the name, first-fit is generally better than best-fit because it leads to less fragmentation.
-         The first fit approach tends to fragment the blocks near the beginning of the list without considering blocks further down the list. Next fit is a variant of the first-fit strategy.The problem of small holes accumulating is solved with next fit algorithm, which starts each search where the last one left off, wrapping around to the beginning when the end of the list is reached (a form of one-way elevator).

Explain relocation of paging system.
Paging permits a program to be allocated noncontiguous blocks of memory. We divide programs into pages which are blocks of small, fixed size. We then divide the physical memory into frames which are blocks of size equal to page size. We use a page-table to map program pages to memory frames.

Rabu, 16 Februari 2011

INPUT & OUTPUT MANAGEMENT


• Managing input & output in Windows XP involves many operating system componets.

• User-mode processes interact with an enviroment subsystem and not directly with kernel-mode componets.

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

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

• The plug and play manager dynamicaly 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 mangement policy.

• The power policy detemines whether to power down devices to conserve energy or keep them fully powered for high responsiveness.


5.3 Elaborate the concept of 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

• Buffee 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, sehinnga 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 buffernya, 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.

























5.4 Recognize spooling technique

• 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.



• This temporary working area would normally be a file or storage device.

• The most common spooling application is print spooling: documents formatted for printing are stored onto a buffer (usually an area on a disk) by a fast processor and retrieved and printed by a relatively slower printer at its own rate.

• Spooler or print management software may allow priorities to be assigned to jobs, notify users when they have printed, distribute jobs among several printers, allow stationery to be changed or select it automatically, generate banner pages to identify and separate print jobs, etc.

• The temporary storage area to which E-mail is delivered by a Mail Transfer Agent and in which it waits to be picked up by a Mail User Agent is sometimes called a mail spool

5.1 Explain on input-output management

• In economics, an input-output model uses a matrix representation of a nation's (or a region's) economy to predict the effect of changes in one industry on others and by consumers, government, and foreign suppliers on the economy

• Input-output depicts inter-industry relations of an economy. It shows how the output of one industry is an input to each other industry

• most uses of the input-output analysis focuses on the matrix set of interindustry exchanges, the actual focus of the analysis from the perspective of most national statistical agencies, which produce the tables, is the benchmarking of gross domestic product

• The mathematics of input-output economics is straightforward, but the data requirements are enormous because the expenditures and revenues of each branch of economic activity have to be represented