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UserOperating system is a very important software that provides the computer a list of instruction on how to run the computer. A computer cannot run without an operating system, the operating system also known as OS provide the computer a list of instruction on how to run and use some function or more like 'how to do thing' explain to the computer. Operating system is a layer of software that separates the applications from the hardware. The operating system also provides an interface for the user and the computer software and hardware. Basically, the OS is a collection of software that manage the computer hardware and software. The operating system also providing a bridge between the user and the computer which as show as the diagram 1.
The Operating system provides the basic instruction for the application that allow the computer to run the application software that are installed in the computer.
The Common Features of Operating System is;
Input and output
Interrupts is a signal that emitted by software or hardware that an event need immediate attention. The OS also help the computer with the memory management; the memory management is very important feature because the system performance can be affected because of a bad memory management. Also the modern operating system contains most of the basic device driver that available on the market. The device driver is software that operates and control device that are attach to the computer. Each device have a different driver that control and manager them. For example a graphic card has its own software or driver to manager it. Drivers allow the computer to communicate with the device. Most of the operating system also comes with some basic security. Most of the security are design to protect memory form been damage. Some example of the operating system come in security; the backup and recovery is a basic security that protect memory, the system will save a copy of the main system file as a backup, we can this recovery point and user can set when the system will set a recovery point or for the advance user they can set a recovery point themselves, if anything happen to the main program file the user can use the recovery like a virus had infected the main program file the user, in this case the user can use the recovery function to restore the system and undo any changes to the system. Also ensuring unauthorized user access the system.
Operating system is a collection of software that control and manager both the hardware and software in the computer system. The OS is also providing user with an interface with the computer. A computer cannot function without an OS; OS also provide some of the basic function to the computer system. Today in the modern world, computer science had become more and more advance. Now there is much type of OS available in the market some are for home office, some for profession, and some are for general user. The most common operating system available on the market is Microsoft Window XP, Microsoft Window Vista, Microsoft Window 7, and Operating System for Apple computer Mac OS. Each of the OS has their own advantage and disadvantage, their own strength and weakness. Firstly, the Window XP develops by Microsoft. Window XP is develop after the Window 2000(2000) and Window ME (2000), Window XP is the second most popular version of Windows OS series, and the name XP is short for "eXPerience" which the window XP goal is to enhance user experience. The benefits of Microsoft window XP is the OS is very fast and have a quick response generative in nature. The window XP is design as a multitasking operating system that mean it allow the user to switch between the application and work on the other application even one of the application are stop working suddenly. Also the computer application can be open within seconds because the boot process is very fast. Another advantage of window XP is the quick delete function, before it will take a long time just to delete files because the user will have to wait until all the file is deleted. The Window XP also will make and sent a report on any error that the user encounter to the Microsoft for solution to preventing any system hangs. Also the Window XP have a universal hardware support that can support most of the hardware available on the market, even when the OS cannot support the hardware user can go online and download the driver needed for the hardware. The Window XP can run on any computer with AMD or Intel processer since 1998. However the window XP is not perfect it also have some disadvantages. One of them is that the window XP cannot install on multiple computer because the product activation key can only been use once meaning the OS can only be install on one computer. If the user have more than one computer on home or office the user have to buy a new license and new activation key which is very expensive. This is a major disadvantage if the user want to install this OS into their computer if their own more than one computer. Another disadvantage of Window XP is RAM limitation, the OS can only support up to 4GB (gigabytes) of RAM (random access memory). If the user want to run an application which require a lot of memory the computer may not able the run the application or slow down the computer. If the user wants to install more RAM he or she has to buy Windows XP Professional x64 or upgrade to newer operating system such as Window Vista or Windows 7. Also for user who using window XP in gaming, The user have to face another problem in graphic the window XP only support DirectX to version 9 as of 2010 most of the game are designed for video card than support DirectX10 and DirectX 11 of which the DirectX is a type of technology created by Microsoft to allow computer work more efficiently on Windows operating system when playing game. The only way is to upgrade the operating system to window Vista or window 7. Also disadvantages is security, as in 2010 the Window XP is one the most widely use OS in the world even with the newer Microsoft design operating system which is the Window Vista and Window 7, because of this there are a lot of virus made to target Window XP operating system so going online without an anti-virus software is dangerous. Another operating system design by Microsoft is the Windows Vista. Windows Vista is an operating system for personal computer which includes the home computer and business computer. The Windows Vista was known by its codename "Longhorn". The Windows Vista is known for its updated graphical user interface and visual style known as Aero and a new search component known as Windows search. The advantages of the windows Vista is the improved graphical user interface call Aero, which the appearance of the window and the desktop are change, the 'look' is better compare the windows XP. Below are the screen shot of both windows
XP and Windows Vista.
Another advantage is the parental control this new include feature allow parents to control how their children using he computer, it can block certain program like game and some internet site. It can set up a profile which the parent can keep track on the activity when their using the computer. Another advantage of the Window Vista is the improved search feature call windows explorer, in the explorer you can got the search result as you type in the keyword in the search box. However there are a lot of disadvantages can be find in windows Vista for one the operating system is slower than the Windows XP, as the Windows Vista is focus on graphic. Also the requirement is very high to install the operating system. The graphic card must be DirectX 10 supported and the minimum graphic memory is 128 MB. The minimum hard disk space required is 20 GB and processor speed need to be fast enough for good performance. Also the price of the Windows Vista is very high so ordinary user cannot access the full feature of the window vista. The windows vista is succeeded by Windows 7 which also design by Microsoft. When designing the windows 7 the goal is to make a more refined version of windows vista aim to correct some disadvantage that windows vista present. The windows 7 are superior to Windows XP and Windows Vista because the speed of the windows 7 is faster than Vista and XP. Windows 7 have fast boot up time and fast installation. Also the window 7 is more stable compare to window vista less chance to experience crash on the windows 7. Also window 7 have large amount of function and gadgets which is no available in other window operating system. These gadgets in sticky note, table clock and many more. However there are some disadvantage like some user having trouble when using the windows 7 because they don't have the experience the use this operating system so only advanced users are convenient with this OS. Also the hardware requirement of the computer is need for install the OS is RAM capacity at least 1 GB. Another OS is Mac OS is a of graphical user interface-based operating systems developed by Apple Inc. the advantages of the Mac OS is security. Mac OS is a two layered system which is the attractive GUI and UNIX core. UNIX is best known for its security feature. It is impossible to install Trojan or virus in the computer running Mac OS unless the users allow it. Another advantage is reliability because the Mac OS is very stable and is unlike crash, the Apple control the production from start to end so the OS is designed and tested to make sure error is at minimum. The disadvantages of Mac OS is the Price, it is expansive just to get a copy of the operating system. Another disadvantage is gaming, this operating system is a closed system it cannot work with anything that is not apple design and there is very little game that design for Mac OS. Also when it comes to software there is less choice for the Mac OS user since most of the software are not able to run on Mac OS.
Virtual memory is an imaginary memory area supported by some operating systems example windows operating system in conjunction with the hardware. Can think of virtual memory as an alternate set of memory addresses. Programs use these virtual addresses rather than real addresses to store instructions and data. When the program is actually executed, the virtual addresses are converted into real memory addresses. Virtual memory refers to the technology in which some space in hard disk is used as an extension of main memory so that a user program need not worry if its size extends the size of the main memory. If that does happen, at any time only a part of the program will reside in main memory, and other parts will otherwise remain on hard disk and may be switched into memory later if needed. Below shown a diagram about virtual memory.
Paging is one of the memory management schemes which a computer can store and retrieve data from secondary storage for use in the main memory. In paging the OS retrieve data from storage in same-size block call pages. The advantages of paging is in the each task has the same virtual address in the address translation. The fragmented physical addresses into contiguous virtual addresses by the address translation. This will provide memory protection and shared memory between tasks. Paging will also help in demand loading which prevent large load on CPU when task first running, conserver memory. Paging requires memory mapped files, Virtual memory swapping which let system degrade when memory required exceeds RAM size. The process can be run which virtual address space is larger than physical memory. The Disadvantages of paging is consuming more resource because the memory is used to store the page table. The worst cases are when page table may take up a significant portion of virtual memory, solution to this problem is to page the page table or go to a more complicated data structure for translations. Other disadvantage is translation overhead.
Segmentation is the division of computer's primary memory into segments or sections. The advantage of segmentation is to allow processes to access the particular memory location for required data. It can directly point to the exact location where the data resides, where decreases the search time and access time because it not searching the entire memory. Another advantages is it can separates the important data from the OS files, when the OS crashes, the user can still retrieve the data after reinstalling the OS in the other sector or segment. The disadvantages is when the segmentation is done, the possibility of losing contiguity in the file is increase. This will slow down the computer system.
Interrupt processing is a computer process. Its state includes the executable code and data in the main memory, the value of the program counter, and the values of all the general-purpose register. When an event or process of higher priority needs to get prompt attention from the CPU, it can interrupt the execution of the current process holding the CPU, save its key state information in memory or hard disk, do whatever interrupt processing with the CPU, then resume the original process's execution by restoring its state in memory and registers. An interrupt is a dynamic event that needs prompt attention by the CPU. After that the original process can resume its execution. There are two types interrupting events: hardware interrupts that are those issued by I/O device controllers when they need CPU to process I/O data, and software interrupts, also called traps, that are raised when the current process executes a special trap instruction to indicate that something wrong has happened or the process needs special service from the operating system (like performing some I/O operation). Only a limited number of types of interrupts are defined. For each type of I/O devices, there is a special program called an interrupt handler to serve the interrupt requests from these devices. For all software traps, there is also a special trap handler defined. Each type of interrupt has an associated priority level. A running process would only be interrupted by an interrupt source or trap of higher priority. When the CPU is executing an interrupt handler, the interrupt handler may be further interrupted by an interrupt source of even higher priority.
Operating system is a very important software that provides the computer a list of instruction on how to run the computer. A computer cannot run without an operating system, the operating system also known as OS provide the computer a list of instruction on how to run and use some function or more like 'how to do thing' explain to the computer. Operating system is a layer of software that separates the applications from the hardware. The operating system also provides an interface for the user and the computer software and hardware. Basically, the OS is a collection of software that manage the computer hardware and software. Virtual memory is an imaginary memory area supported by some operating systems example windows operating system in conjunction with the hardware. Can think of virtual memory as an alternate set of memory addresses. Programs use these virtual addresses rather than real addresses to store instructions and data. When the program is actually executed, the virtual addresses are converted into real memory addresses. Virtual memory refers to the technology in which some space in hard disk is used as an extension of main memory so that a user program need not worry if its size extends the size of the main memory. Interrupt processing is a computer process. Its state includes the executable code and data in the main memory, the value of the program counter, and the values of all the general-purpose register. When an event or process of higher priority needs to get prompt attention from the CPU, it can interrupt the execution of the current process holding the CPU, save its key state information in memory or hard disk, do whatever interrupt processing with the CPU, then resume the original process's execution by restoring its state in memory and registers. An interrupt is a dynamic event that needs prompt attention by the CPU. After that the original process can resume its execution.