Java Development Kit And Java Runtime Environment Computer Science Essay

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Today, it is widely recognized computer is really essential for the entire world. During the 21th century, many people were realize using computer could help them successful a lot of things with easier, either thats for calculation or management. Of course, besides the hardware and software component, there has a most important thing to keep a computer system working smoothly, which is the operating system. Even though many people are using computer, but most of them doesnt know how it actually work and why we need operating system to work for, therefore in the assignment, we would discuss about the operating system.

In this assignment, it had been recognized in four sections, which are introduction, content conclusion and references. Each section we would go in to details. For the first question in this assignment, we would discuss about the several kind of operating system which is available in market today and it performances as well. Therefore, based on this section we will create and explain some comparison and contrast with every type of operating system. After that, we would talk about some detail of Virtual Memory with Paging and Virtual Memory with Segmentation within second question. In this part, we would also make some comparison with these two kinds of Virtual Memory, and some detail about interrupt process.

As a conclusion, the purpose of this assignment is to present as possible as clearly and completely, the characteristics and nature of modern-day operating system. Although most of the resources of this assignment are taken from internet and reference book, the objective is to present the material in a fashion that keeps new material in a clear context to those readers.

2.0 Definition of Question 1

To understand an operating system how does it work, mostly is like to understand the entire computer system. A computer system has consists a lot of software and hardware, typically which have included the program and physical machine or its electronic component as well. In addition, as known as the operating system software mostly is like a chief piece of the software, which is the portion of the component system for manage the entire hardware and software. Generally, it has been use to control every file, device, the section of main memory, and the nanosecond of processing time. Therefore, as we can say operating system is like a boss, because it was control the entire system that who could be use. For describe the process of operating system, the operating system would make sure the command is executed while user was send a command, if that is not executed, it would arrange for the user to get a message and explain the error. In this condition, the one thing important to remember is the operating system has not necessary for executed the command or sends the error message, but it was the main of does control the part of the system.

3.0 The Comparison of Operating System

During the 21th century, the technology of operating system was become more popular. Based on the market today, there have many different types of competing operating system are available in use. Those are the types of operating system have amassed its popularity for the different reasons. Typically, most of the people while choosing the operating system is depend on their different usage. Therefore, based on this section, we would make some comparison between Microsoft Window and Macintosh.

3.1 Microsoft Windows

Windows is a software operating system and graphic user interface which was developed by Microsoft. During its introduction in 1985, Windows are immensely popular than other brands of personal computer. Typically, there have two parallel routs for its development, which are personal and professional use. The different of its rout is the personal use greater multimedia support but lacked networking capability. Compare to professional version, it offer greater networking and security feature but lacked of multimedia support. Besides that, to compare all versions of Windows, the Windows XP was a greater success and the relatively recent the Windows Vista is nevertheless popular.

3.2 Macintosh

Macintosh as we known as Mac, Macintosh could be refers to a brand name that covers a series of personal computers developed by Apple Inc. In fact, the Apple was produces all of the hardware of Mac and it also provide its own operating system for comes package with Mac. Typically, Mac operating system could be classified in two families of the operating system. Classic Mac OS is one of the versions which had shipped with the Mac until the creation of Mac OS 9. The second is Mac OS X, which was deriving its feature from the Mac OS 9. The Mac OS X is one of the operating system that was currently in use and successor of Mac OS, those are this was a line of graphical user interface-based in operating system.

3.3 Customizability & Hardware

First of all, there one of the reason why Windows computer have many people prefer to use, because it can easy allow user to be customize, although their hardware is designed, the user can replace the graphic card, RAM chip, CD driver, motherboard or another internet hardware at their direction. Compare to Mac models, it was difficult to upgrade apart from RAM to a few basic hardware components. Therefore, most of Apple customer should visit to an Apple store, while they have any change require.

3.4 Operating System Design

For the Windows system design, in the lower left-hand corner of the Windows screen, almost has its main-menu Start button, though this could be altered by the user. In fact, this is where from the programs list, folder and setting that could straight away to accesses, which purpose to allow user easier to make a use of Windows Explorer, and it also a file browsing system. Although the Macs utilize the Finder is much like a Windows Explorer, but it except this basic for all the file are almost on its system. Instead of a My Document folder or All Program list, the document folders and its application were place in the sidebar to the left, apart from this, the way of their folders and file were access on the similar that between both systems.

3.5 Price

Since most of the hardware components of Windows computer are constructed from various manufactures, the end price of it is rather inexpensive. Just because of Mac computer having a greater hardware restriction and less customizable, its price is higher than many model of Windows computers. In fact, the Windows computer could be customized down to a very finite detail, while the Mac was built by choosing a base model, after selected a few upgrades within the various categories.

3.6 Software Availability

For the comparison between these two operating system, there have much more software was available for the Windows than for Mac, and that why Windows is much widely used than the Mac operating system. One of the common reason is there have many would choosing Windows, because since the gamer developer dont choose the Mac operating system to make a separate version, there have many titles werent available for Mac. However, since there have many utility and program were design exclusively for the Mac operating system, the Mac user also could install Windows on their Mac PC or either dual-boot between the both systems within the computer. But on contrary, when install the Mac operating system onto the Windows machine, it doesnt support by either that is Microsoft or Apple.

3.7 Security

The one of the security issue to make Windows popularity become shortfall, the Windows has been suffer the most with the virus, adware, spyware and the other malicious software. It also is the most viruses suffer operating system than the other. In fact, there also have some malicious program made for the Mac operating system as well, but in Mac there is not infected nearly as often. Therefore, most of the people said Mac would never get virus is the false. In addition, both of these two operating system are also have its antispyware program, but Mac user are experience less variety, most of the antispyware program are made for the Windows system.

3.8 Operations

On the part of operation, the Windows and Mac have a rather different style of its operation apart from the basic function, such as copy and paste. For example, while install any program onto the Windows program, it should be follow a number of step of the installation process, but depend on the process of Mac application installation, it just need to clicking and dragging the icon of which application that you would need to install into the Applications folder. Likewise, the program which needs to uninstall in Windows, it should via the Add or Remove Program utility to success. While the Mac user is just only delete its icon inside the Application folder.

4.0 Definition of Question 2

The virtual memory is the feature develops which for the kernel of the operating system that used to simulate the additional main memory, such as random access memory (RAM) or the others disc storage. This technique has involving some management and manipulation of memory which allowing the execution and loading of the larger program or some else the multiple program simultaneously. Besides that, the virtual memory are also allowing each program to operate while it had an infinite memory, and it was able to consider more cost effective than the purchasing additional RAM.

However, the virtual memory was permitting much more software to using the additional memory by the hard disc drive (HDD) as a temporary storage. Most of the central processing unit (CPU) has been providing some memory management unit (MMU) that use to support virtual memory. In fact, the MMU are support the page table which was be used to transform the virtual and the real address located within the memory and onto the HDD.

Most of the operating system was using the virtual memory to free up the space, which was transferring the data from the HDD and its not an immediately required. Therefore, when those of the data were needed to be use, it would copy back to the HDD. Otherwise, when the entire RAM is being to use, the virtual memory would swaps the data to HDD and again turn back. So, the virtual memory could allow the larger total system memory, anyway the complicated code should be required.

5.0 Demand Paging

Demand paging introduce the concept of only loading a part of the program which into the memory for its processing. The demand paging was the first and widely used the scheme that removed the restriction of having the entire job within the memory, from the beginning until the end of its processing. With the demand paging, the jobs were still divide to an equally size page, which was initially reside into the secondary storage. However, when the jobs are beginning to run, its page would bring into the memory which the only as they are needed.

6.0 Segmented Memory Allocation

The concept of segmentation mostly is base on the common practice by the programmer of structuring their program within the modules, such as logical grouping of the code. With the segmented memory allocation, each job would be divide into several segment with the different size, one for each of the module would contain a pieces to perform the related function. The purpose of segmented memory allocation design is use to reduce some page fault that has been resulted from having the segment loop split that over two or else much more pages. For the example, the subroutine is the one of the logical group. This was a fundamentally different with the paging scheme, which divided the job into the several page with all of the same size and it often to contain a piece from more than one program module.

7.0 The Comparison

Since the demand paging would make it possible for the entire program to execute, even though there just have an only part of the program would loaded into the main memory. During the second generation, the programmer may started divide their program into the section for resemble working set, a really segment, originally called roll in or roll out and now is called overlays. Most of the program could begin with the only first overlay load into the memory. As the first section was nearing completion, it could use to instruct the system to lay the second section of the coding, and its much over the first section which already in the memory. Then, the second section will be processed. After the section has been finished, it would call in the third section for overlay within the main memory.

Although the swapping of the overlay is between the main memory and the second storage is done by the system, the tedious tasks of dividing the program in section are done by the programmer. However, it was the overlay concept that has been suggested the paging and segmentation and led to the virtual memory, which is the implementation though the demand paging and segmentation scheme. Below table would show the comparison of virtual memory of paging with segmentation.

Virtual Memory with Paging

Virtual Memory with Segmentation

Allow internal fragmentation within page frames.

Doesnt allow internal fragmentation.

Doesnt allow external fragmentation.

Allow external fragmentation.

Program was divided into equal-sized page.

Program was divided into unequal-sized segment that contain a logical grouping of code.

The absolute address is calculated using page number and displacement.

The absolute address is calculated using segment number and displacement.

Requires PMT.

Requires SMT.

The segmentation would allow for sharing the program code that among the user. Which means that the shared segment have contains an area where has an unchangeable code (also call as reentrant code) was stored, and