TUGASAN 1
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 paging or swapping to secondary storage. The quality of the virtual memory manager can have a big impact on overall system performance.
Objectives Memory Management
- To provide a detailed description of various ways of
- Memory management allows you to make sure that precious memory space isn't taken up by objects that no longer have a purpose in your application, and that objects that are still needed continue to exist. After an object has been created and you finish using it, it will need to be disposed of so that memory isn't taken up needlessly.
- When an object becomes detached from an application's control without being "de-allocated," memory is wasted.
- including paging and segmentation.
Concept Memory Management
- Protection of memory required to ensure correct operation.
- Memory is central to the operation of a modern computer System. Memory consists of a large array of words or bytes each with its own address. The CPU fetches instructions from memory according to the value of the program counter. These instructions may cause additional loading from and storing to specific memory addresses. I have discussed a typical instruction-execution cycle in the previous article. In this article I will discuss on basic hardware issues, the binding of symbolic memory addresses to actual physical addresses and distinguishing between logical and physical addresses.
virtual memory implementation
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage (such as random-access memory and disk storage), allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which behaves like directly addressable read/write memory (RAM).
- use hardware memory more efficiently than do systems without virtual memory
- the program has, by default, sole access to this virtual RAM module as the basis for a contiguous working memory.
Segmentation
- Memory-management scheme that supports user view of memory
- A program is a collection of segments. A segment is a logical unitsuch as:
- procedure
- function
- method
PAGING
- · Logical address space of a process can be noncontiguous; process is allocated physical memory whenever the latter is available
- · Divide logical memory into blocks of same size called pages
- · Keep track of all free frames
- · To run a program of size n pages, need to find n free frames and load program
- · The main advantage of paging is that it allows the physical address space of a process to be noncontiguous
Explain memory relocation of paging system
In computer operating systems, paging is one of the memory-management schemes by which a computer can store and retrieve data from secondary storage for use in main memory. In the paging memory-management scheme, the operating system retrieves data from secondary storage in same-size blocks called pages. The main advantage of paging is that it allows the physical address space of a process to be noncontiguous. Before the time paging was used, systems had to fit whole programs into storage contiguously, which caused various storage and fragmentation problems.
TUGASAN 2
INPUT & OUTPUT MANAGEMENT
- Management Data Input/Output (MDIO), or also Media Independent Interface Management (MIIM), is a serial bus defined for the Ethernet family of IEEE 802.3 standards for Media Independent Interface, or MII. The MII connects Media Access Control (MAC) devices with Ethernet physical layer (PHY) circuits.
- 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.
- input output management also becomes one of the primary responsibilities of an operating system. In this chapter we shall examine the role of operating systems in managing IO devices.
Elaborate the concept of buffering
- The program is so complex, sehinnga programmers themselves do not know the weaknesses of the program
- The paradigm of "buffering" is used increasingly for the description of diverse "systemic" phenomena encountered in evolutionary genetics, ecology, integrative physiology, and other areas.
- The units allow either the time-independent, "static" buffering properties or the time-dependent, "dynamic" ones to be measured. Analogous to this "resistance to change", one can define and measure the "conductance to change"; this quantity corresponds to "set-point tracking" in feedback-control systems.
- Relies on external data to control the program
Recognize spooling technique
- 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.
- 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.
- This temporary working area would normally be a file or storage device.
-
Also referred to as simply a file system or file system.
- For example, a hierarchical file system is one that uses directories to organize files into a tree structure.
- A file system (filesystem) is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device(s) which contain it. A file system organizes data in an efficient manner and is tuned to the specific characteristics of the device.
- There is usually a tight coupling between the operating system and the file system. Some filesystems provide mechanisms to control access to the data and metadata. Ensuring reliability is a major responsibility of a filesystem. Some filesystems provide a means for multiple programs to update data in the same file at nearly the same time.
- These systems interact smoothly with the operating system but provide more features, such as improved backup procedures and stricter file protection.
- File sharing is the practice of distributing or providing access to digitally stored information, such as computer programs, multimedia (audio, images, and video), documents, or electronic books. It may be implemented through a variety of ways
- Network File System (NFS) is a common distributed file-sharing method
- file sharing include manual sharing using removable media
- Directory structure is the way an operating system's file system and its files are displayed to the user.
- Backups of these two structures are kept on tapes
- A collection of nodes containing information about all files.
- Files are typically displayed in a Hierarchical tree structure
- These mapping files were created for converting data to Unicode.
- A file view is the portion of virtual address space that a process uses to access the file's contents.
- The first step in mapping a file is to open the file by calling the CreateFile function. To ensure that other processes cannot write to the portion of the file that is mapped, you should open the file with exclusive access.
- Processes can also manipulate the file view with the Virtual Protect function.
TUGASAN 4
Recognize security policy and mechanism.
- In computer science, protection mechanisms are built into a computer architecture to support the enforcement of security policies. A simple definition of a security policyset who may use what information in a computer system.Mechanism for controlling theaccess of programs, processes, or users the resources defined by the computersystem. the protentation mechanism ensures the enforcement of a certain policy.Password
- · A password is a secret word or string of characters that is used for authentication, to prove identity or gain access to a resource (example: an access code is a type of password). The password should be kept secret from those not allowed access.
- A completely different approach to authorization is to check to see
if the user has some item, normally a plastic card with a magnetic stripe on it.The card is inserted into the terminal, which then checks to see whose card it is.- Another technique is signature analysis. The user sign his name with a special
pen connected to the terminal and the computer compares it to a knownspecimen stored online
Biometric Technique
- Yet another approach is to measure physical characteristic that are hard to forge. For example a finger print or a voiceprint reader in the terminal could verify the users identity (it make the search go faster if the user tells the computer who he is, rather then making the computer compare the given fingerprint to the entire database) Finger length analysis is surprisingly practical. When this is used each terminal has a device. The user inserts his hand into it and the length of all his finger is measured and check against the database.
Elaborate protection concept and access control.
- For your PC security suite is now available a variety of programs that promise more often than full protection from malware, with acontrol virus and malware, but also with some research andcomplex in real time.
- Major challenge for all manufacturers areoffering solutions that are effective yet easy to use, and if you do not require excessive resources to the system.
- At the time all the leading manufacturers of security software suite that provides a guide as well as the traditional functions of malwaredetection and protect your PC also features accessories forprotection of data and optimization of the operating system.
- The concept of security was also extended to the area where this malware is not in the strict sense. But, in a sense, a proper backup data fall within the concept of security
Install or Format Windows 7
- 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 ).
- 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.
- Press Install Now
- After a min you will be asked for your Product Key. Enter your product key.
- Accept the Microsoft Windows User License Terms and press Next
- Dialog – “Which type of installation do you want ?”
- If you already have another operating system installed (ex. Windows XP) you will have the Upgrade option enabled.But if you want to format your drive, deleting the old system and installing fresh Windows Vista copy.
- Select the drive you want to install and click next
- The installation process will begin.
- After Windows Vista Setup finishes, the computer will reboot.
- Windows Vista files are copied , and now setup will configure Windows Vista for your PC.
- Insert your User Name and Password for user account
- Select your preferred security settings. If this computer is not behind a firewall, the best option is the ” Use Recommended settings”.
- Select your time zone and location.
- Network Configuration – Select your computer location. This settings sets your network permissions.
- The installation of Windows Vista has completely finished
