Total Price

External

$1434

Internal

$1667

Total $3101

A Description of the different PC and Macintosh Operating Systems

A description of the different PC and Macintosh Operating System

Mac computers run on the operating system OS X. You can run Windows or Linux on a Mac, but OS X is the default operating system of Mac computers. Legally, OS X is only supposed to be used on Mac computers. Apple has gone to great lengths to make sure of this. Macs OS X uses distinct programs and applications. For example, DMG is an extension used by Mac computers. A BMW is factory tuned to be a performance car, and BMW wheels will only work with a BMW.

PCs are best known for running on the operating system Windows. However, Windows has nothing to do with a PC being a PC. Many people prefer the open source operating system Linux. You cannot legally install OS X on a PC. PC operating systems, such as Windows, use distinct programs and applications. For example, EXE is an extension used by Windows based PCs. When restoring a Chevy Camaro, you can choose whether or not you want blue or black gauges in it.

The Relationship between an Application Program, the Operating System and Hardware

The relationship between an Application Program, the OS, and Hardware

The Relationship between an Application Program, the Operating System and Hardware

COmputer software can be divided into two main categories: application software and system software. According to Brookshear [1997], "application software consists of the programs for performing tasks particular to the machine's utilization. Examples of application software include spreadsheets, database systems, desktop publishing systems, program development software, and games." Application software is generally what we think of when someone speaks of computer programs. This software is designed to solve a particular problem for users.
On the other hand, system software is more transparent and less noticed by the typical computer user. This software "provides a general programming environment in which programmers can create specific applications to suit their needs. This environment provides new functions that are not available at the hardware level and performs tasks related to executing the application program" [Nutt 1997]. System software acts as an interface between the hardware of the computer and the application software that users need to run on the computer. The diagram below illustrates the relationship between application software and system software.

The most important type of system software is the operating system. According to Webopedia [2000], an operating system has three main responsibilities:
Perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.
Ensure that different programs and users running at the same time do not interfere with each other.
Provide a software platform on top of which other programs (i.e., application software) can run.
The first two responsibilities address the need for managing the computer hardware and the application programs that use the hardware. The third responsibility focuses on providing an interface between application software and hardware so that application software can be efficiently developed. Since the operating system is already responsible for managing the hardware, it should provide a programming interface for application developers.
Nutt [1997] identifies four common types of operating system strategies on which modern operating systems are built: batch, timesharing, personal computing, and dedicated. According to Nutt, "the favored strategy for any given computer depends on how the computer is to be used, the cost-effectiveness of the strategy implementation in the application environment, and the general state of the technology at the time the operating system is developed." The table below summarizes the characteristics of each operating system strategy as described by Nutt [1997].
Batch

This strategy involves reading a series of jobs (called a batch) into the machine and then executing the programs for each job in the batch. This approach does not allow users to interact with programs while they operate.
Timesharing

This strategy supports multiple interactive users. Rather than preparing a job for execution ahead of time, users establish an interactive session with the computer and then provide commands, programs and data as they are needed during the session.
PersonalComputing

This strategy supports a single user running multiple programs on a dedicated machine. Since only one person is using the machine, more attention is given to establishing predictable response times from the system. This strategy is quite common today because of the popularity of personal computers.
Dedicated

This strategy supports real-time and process control systems. These are the types of systems which control satellites, robots, and air-traffic control. The dedicated strategy must guarantee certain response times for particular computing tasks or the application is useless.

A Description of the Boot Process

In computing, booting is a process that starts operating systems when the user turns on a computer system. a boot sequence is the initial set of operations that the computer performs when power is switched on. The boot loader typically loads the main OS for the computer.

When we press the computer power to make the computer starts, and Windows XP Professional operating system to start, we call this period the pre-boot (Pre-Boot) stage, at this stage, the computer first run Power On Self Test (POST ), POST test the system’s total memory and other hardware equipment, the status quo. If the computer system BIOS (basic input / output system) is a plug and play, then the computer hardware equipment will be tested, as well as complete the configuration. The computer’s basic input / output system (BIOS) to locate the computer’s boot device, and then MBR (Master Boot Record) is loaded and run. In the pre-boot phase, the computer to load Windows XP, NTLDR file.

b) guided phase

Windows XP Professional boot phase consisted of four small stage.

First of all, the computer has to go through the initial boot loader phase (Initial Boot Loader), in this phase, NTLDR computer microprocessors from real mode to 32-bit flat memory model. In real mode, the system for MS-DOS reserved 640kb of memory, the remaining memory as extended memory, and in the 32-bit flat memory mode, the system (Windows XP Professional) depends on all the memory available memory. Then, NTLDR starts the built-in mini-file system drivers, through this step, so that NTLDR can identify each of a file system using NTFS or FAT formatted partition in order to detect and load the Windows XP Professional, here, the initial boot loader phase is over.

Then the system came to the operating system selection phase, if the computer is installed on more than one operating system (that is, multi-system), and the boot.ini is set correctly so that system under the conditions of the operating system of choice, the computer monitor will show an operating system menu, This is the NTLDR reads the boot.ini results.

In the boot.ini, mainly includes the following:

　　[boot loader]

　　timeout=30

　　default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS

　　[operating systems]

　　multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=”Microsoft Windows XP Professional” /fastdetect

　　multi(0)disk(0)rdisk(0)partition(2)\WINNT=”Windows Windows 2000 Professional”

In it, multi (0) mean disk controller, disk (0) rdisk (0) mean disk, partition (x) is partition. from here NTLDR will find the location of Windows XP Professional system files.If the boot.ini is only one operating system option, or the timeout value is set to 0, then the system does not appear the operating system selection menu and directly into the system or the default system. When start Windows XP Professional, the operating system selection phase is completed.

In hardware detection phase,ntdetect.com will collect information about computer hardware list and return it to the NTLDR, the purpose of doing this is to add the hardware information into the registry under the HKEY_LOCAL_MACHINE.

Hardware detection is complete, enter the configuration options stage. If the computer contains multiple hardware profiles list, you can press the down button to select. If there is only one hardware profile, the computer does not display this screen but directly using the default configuration file to load Windows XP Professional.

End of the guide period. In the boot stage, the system should use those file: NTLDR, Boot.ini, ntdetect.com, ntokrnl.exe, Ntbootdd.sys, bootsect.dos (optional).

c) loaded the kernel stage

Loaded kernel stage, ntldr load known as the Windows XP kernel ntokrnl.exe. System loaded Windows XP kernel but did not initialize it. Then ntldr loads the hardware abstraction layer (HAL, hal.dll), then the system continues to load HKEY_LOCAL_MACHINE \ system keys, NTLDR reads the select button to determine which Control Set will be loaded. Control set that contains the device drivers and the need to load the service. NTLDR loads HKEY_LOCAL_MACHINE \ system \ service \ … Next start key value is 0 the lowest device driver. When a Control Set the Current Control Set the mirror is loaded, ntldr to pass control to the kernel, the kernel initialization phase begins.

In the kernel initialization stage,the color logo of Windows XP as well as the progress bar displayed in the center of the screen, at this stage, the system completed its start four tasks:

The kernel used in the hardware detection data collected to create the HKEY_LOCAL_MACHINE \ HARDWARE key.

Kernel by reference HKEY_LOCAL_MACHINE \ system \ Current Copy Control Set the default values to create a Clone Control Set. Clone Control Set configuration backup of computer data, not including the initiation of the changed and will not be modified.

System complete initialization, and loading device drivers, kernel initialization phase of those who load the kernel is loaded the bottom of the driver, and then the kernel scanner HKEY_LOCAL_MACHINE \ system \ CurrentControlSet \ service \ … device driver which key value is 1. These device drivers are loaded when the initialization has completed, if an error occurs, the kernel used ErrorControl key to determine how to deal with a value of 3, the error flag for the crisis / critical,at first time the system will restart encountered LastKnownGood Control if there is an error, if you are using LastKnownGood Control Set to start is still an error, the system fails to start,it will report the error message and the system stop start; a value of 2 as a serious error condition, the system fails to start and to restart the LastKnownGood Control Set , if the system starts already in use LastKnownGood value, it will ignore the error and continue to start;.

Session Manager start Windows XP Advanced Subsystem and services, Session Manager control all input and output devices, and access to display screen as well as the Win32 subsystem Winlogon process, initialize the kernel is completed.

d) landing

Winlogon.exe start Local Security Authority, while Windows XP Professional visit the Welcome Screen and dialog box is displayed, at this time,the system may continue deal with driver which has not completed in the background.

Prompted to enter a valid user name or password.
Service Controller finally scan HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Servives to check whether there are service needs loads, Service Controller check start key 2 or more of service, service will loading in accordance with start values and the values of DependOnGroup and DepandOnService.

Only after the user successfully logged on to the computer, Windows XP startup can be considered complete, after a successful landing, the system copies Clone Control Set to LastKnownGood Control Set, complete this step, the system has been successfully guided.

When you hit the power button on your computer a whole lot of stuff happens. We call this the boot process. In the days when I first started using computers there was literally a "boot disk", a floppy (5.25" not a 3.5") disk that told the system where to go and what to do so that the operating system would start up. Since then the boot sequence has become somewhat more complicated. So let me take you thru the steps the computer takes to get started. For my example I'm going to use a Windows XP system.

1. First is the POST, this stands for Power On Self Test, for the computer. This process tests memory as well as a number of other subsystems. You can usually monitor this as it runs each test. After that is complete the system will run POST for any device that has a BIOS (Basic Input-Output System). An AGP has its own BIOS, as do some network cards and various other devices.
2. Once the POST is complete and the BIOS is sure that everything is working properly, the BIOS will then attempt to read the MBR (Master Boot Record). This is the first sector of the first hard drive (called the Master or HD0). When the MBR takes over it means that Windows is now in control.
3. The MBR looks at the BOOT SECTOR (the first sector of the active partition). That is where NTLDR is located, NTLDR is the BOOT LOADER for Windows XP. NTLDR will allow memory addressing, initiate the file system, read the boot.ini and load the boot menu. NTLDR has to be in the root of the active partition as do NTDETECT.COM, BOOT.INI, BOOTSECT.DOS (for multi-OS booting) and NTBOOTDD.SYS (if you have SCSI adapters)
4. Once XP is selected from the Boot Menu, NTLDR will run NTDETECT.COM, BOOT.INI and BOOTSECT.DOS to get the proper OS selected and loaded. The system starts in 16-bit real mode and then moves into 32-bit protected mode.
5. NTLDR will then load NTOSKRNL.EXE and HAL.DLL. Effectively, these two files are windows XP. They must be located in %SystemRoot%System32.
6. NTLDR reads the registry, chooses a hardware profile and authorizes device drivers, in that exact order.
7. At this point NTOSKRNL.EXE takes over. It starts WINLOGON.EXE that in turn starts LSASS.EXE, this is the program that display the Logon screen so that you can logon.

The Functions of a Computer Operating System

The Functions of a Computer Operating System

Operating System Functions What is an Operating System An operating system is software, consisting of programs and data, that runs on computers, manages computer hardware, and provides common services for execution of various application software. What does a driver do? A driver is a specially written program which understands the operation of the device it interfaces to, such as a printer, video card, sound card or CD ROM drive. It translates commands from the operating system or user into commands understood by the the component computer part it interfaces with. It also translates responses from the component computer part back to responses that can be understood by the operating system, application program, or user. The below diagram gives a graphical depiction of the interfaces between the operating system and the computer component.

Other Operating System Functions

The operating system provides for several other functions including:

• System tools (programs) used to monitor computer performance, debug problems, or maintain parts of the system.
• A set of libraries or functions which programs may use to perform specific tasks especially relating to interfacing with computer system components.

The operating system makes these interfacing functions along with its other functions operate smoothly and these functions are mostly transparent to the user.

Operating System Concerns

As mentioned previously, an operating system is a computer program. Operating systems are written by human programmers who make mistakes. Therefore there can be errors in the code even though there may be some testing before the product is released. Some companies have better software quality control and testing than others so you may notice varying levels of quality from operating system to operating system. Errors in operating systems cause three main types of problems:

• System crashes and instabilities - These can happen due to a software bug typically in the operating system, although computer programs being run on the operating system can make the system more unstable or may even crash the system by themselves. This varies depending on the type of operating system. A system crash is the act of a system freezing and becoming unresponsive which would cause the user to need to reboot.
• Security flaws - Some software errors leave a door open for the system to be broken into by unauthorized intruders. As these flaws are discovered, unauthorized intruders may try to use these to gain illegal access to your system. Patching these flaws often will help keep your computer system secure. How this is done will be explained later.
• Sometimes errors in the operating system will cause the computer not to work correctly with some peripheral devices such as printers.

Operating System Types

There are many types of operating systems. The most common is the Microsoft suite of operating systems. They include from most recent to the oldest:

• Windows XP Professional Edition - A version used by many businesses on workstations. It has the ability to become a member of a corporate domain.
• Windows XP Home Edition - A lower cost version of Windows XP which is for home use only and should not be used at a business.
• Windows 2000 - A better version of the Windows NT operating system which works well both at home and as a workstation at a business. It includes technologies which allow hardware to be automatically detected and other enhancements over Windows NT.
• Windows ME - A upgraded version from windows 98 but it has been historically plagued with programming errors which may be frustrating for home users.
• Windows 98 - This was produced in two main versions. The first Windows 98 version was plagued with programming errors but the Windows 98 Second Edition which came out later was much better with many errors resolved.
• Windows NT - A version of Windows made specifically for businesses offering better control over workstation capabilities to help network administrators.
• Windows 95 - The first version of Windows after the older Windows 3.x versions offering a better interface and better library functions for programs.

There are other worthwhile types of operating systems not made by Microsoft. The greatest problem with these operating systems lies in the fact that not as many application programs are written for them. However if you can get the type of application programs you are looking for, one of the systems listed below may be a good choice.

• Unix - A system that has been around for many years and it is very stable. It is primary used to be a server rather than a workstation and should not be used by anyone who does not understand the system. It can be difficult to learn. Unix must normally run an a computer made by the same company that produces the software.
• Linux - Linux is similar to Unix in operation but it is free. It also should not be used by anyone who does not understand the system and can be difficult to learn.
• Apple MacIntosh - Most recent versions are based on Unix but it has a good graphical interface so it is both stable (does not crash often or have as many software problems as other systems may have) and easy to learn. One drawback to this system is that it can only be run on Apple produced hardware.

The Environment Consideration of Computer Hardware and OH+S Considerations in the Use of Computer Equipment

Old Hardware May Contain Dangerous Elements

Used computer hardware or monitors are a source of some useful elements like copper and lead: but other harmful substances reside in your old hardware that, improperly discarded, pose serious problems for environmental and human health. Some of the worst parts of discarded computer hardware include:

* Mercury in flourescent tubes

* Cadmium and other potential toxins in laptop batteries and energy sources

* Lead in circuitry

In addition to these known dangers, it's important to point out that there are also more subtle elements in computer hardware that could be getting into our environment and even our bodies! Conflicts like this one reported in U.S.A. Today show that some are concerned about plastics in consumer devices that can get into our bodies in traceable amounts that can build up over time. Issues like these add to the need for responsible use of old hardware and appliances.

SETTING UP YOUR WORKSTATION

With the increasing availability of computers within the work place it is important for all members of staff to be aware of their working environment and how best to set it up. The following guide provides general advice for users of screen-based equipment.

The information is designed to assist the majority of users without pre-existing back, neck or shoulder problems.

This Guide should be used in conjunction with the Workstation Checklist. The purpose of this checklist is to provide the tool for members of staff to undertake an initial assessment of the set up of their workstation to help assist in achieving and maintaining good ergonomic work practices.

If after having carried out the self-assessment you have a concern regarding your workstation or you are not comfortable carrying out a self-assessment then a request for a formal work station assessment may be made to the Occupational Health and Safety Consultant via your manager.

This Guide includes information contained in the Victorian Workcover Authority(VWA) publication Officewise - A guide to health and safety in the office.

YOUR WORKSTATION - THE CHAIR
SEAT: Height: Raise/lower the seat to enable the desk height to be at your elbow height. If you are a "touch typist", you may sit slightly higher. Adjust chair height so the feet are comfortably flat on the floor, the thighs are approximately horizontal and the lower legs approximately vertical. Tilt (if available) Set to horizontal initially, although you may wish to adjust the tilt slightly forward to suit your comfort.
BACK REST: Height: Move the backrest to locate the lumbar support to the curve of your lower back. Lock the backrest into place. Angle: Use your body weight to lean back against the backrest. Depress the control lever to enable the back rest to change the angle. Frequent posture changes encourages blood flow to different muscle groups which helps minimize back fatigue when sitting for prolonged periods.
ARM RESTS: Armrests are usually not recommended unless they are well out of the way of the desk. However, if your chair has arm rests make sure that they do not prevent you from getting as close to the desk as you require or that they impinge on your elbows while you are working FOOT RESTS: Use a foot rest if you feel pressure under your thighs from the front edge of your seat. A foot rest is also useful to address lower back fatigue when sitting for long periods. Pushing your feet into the foot rest helps to push your back into the angled back rest of the chair.

YOUR WORKSTATION - THE DESK
POSITION ON THE DESK Place the keyboard as close to the front edge of the desk as is comfortable. Do not place documents between the keyboard and the front edge of the desk, as this increases the reach distance to the keyboard and may result in excessive bending of the neck to look at the documents. Where possible, layout should be reorganised to bring frequently used objects closer to the user
POSITION OF YOUR MOUSE AND KEYBOARD Both these items are used frequently and should be located on the desk in the primary reach area. Keyboards: Touch typist should locate the keyboard close to the desk edge. Non touch typists should locate the keyboard around 10 cm in from the desk edge. This enables Desk space to rest the hands when not typing. Reduce the neck angle when looking between the keyboard and monitor.
Mouse: The elbow should remain bent when reaching for the mouse. The mouse should be located in the primary area. Your forearm should rest on the desk when you hand is on the mouse. It should glide over the desk when using the mouse. Train yourself to use a mouse with either hand. Learn keyboard short cuts for frequent mouse activities and reduced the use of the mouse When mainly using the mouse, locate it directly in front of you and use your other hand for minor keyboard corrections. Do not continue to grip the mouse, when it is not in use. Do not hover your hand over the mouse, rest it on the mouse or desk. Telephone: Consider locating the telephone on your non-dominate side of the computer. However do not reach across your body to answer the phone to use your non-dominant hand. If it is frequently used, locate it in the primary reach area. If you have frequent or prolonged calls, consider using a headset when accessing computer data. DO NOT cradle the phone between your shoulder and your ear.

YOUR WORKSTATION - THE COMPUTER SCREEN
The computer screen The screen should be positioned once the chair and desk heights have been established. Height The screen should be positioned so that the top of the screen is level with, or slightly lower than, your eyes when you are sitting upright. Either raise or lower the screen to achieve the desired height. Distance from the eye The monitor should be at least a full arms length away from your seated position.
NOTEBOOK COMPUTERS Laptop computers are increasingly being used in place of a desktop computer. Laptops were designed for short term or mobile use. This can result in the work height being unsuitable plus as a general rule the keyboards are not designed for long-term use. If you are regularly using a laptop computer the screen should be raised to the correct height, as detailed above, and a standard keyboard utilized in place of the laptop keyboard.
CLUTTER Power leads, boxes and files rubbish bins and general clutter stored underneath your desk decrease or interferes with space required for your legs. This may force you to adopt a twisted or an awkward posture of the spine.
REST AND EXERCISE FOR THE FIT & UNFIT Our bodies are not designed to sit in one position for extended periods, even with a correctly designed workstation. If we were, we would've been born with casters on our feet and cushions permanently attached to the appropriate part of our body. Rest and Exercise Breaks If appropriate, rest pauses should be taken prior to the onset of fatigue (every 20-30 minutes if a change of activity is not imminent). Exercise breaks may be necessary where task variety is not available and restricted postures are prolonged. The aim is to provide dynamic movement when static postures are maintained.

External hardware components and peripherals, cost, image and function

1. Monitor

The monitor I have chosen is an HP LP2475w 24-inch Widescreen LCD Monitor, the cost is $999. This is used to display output created from the use of various computer programs.

2. Printer (Multi Function Device)

The printer I have chosen is HP LaserJet Pro M1212nf All in One Laser Printer the cost is $140. This is used to print, scan, and copy files.produces a text and/or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies.

3. Modem

The modem I have chosen is Billion BiPac 7800N Wireless the cost is $175. This is used to connect the computer to the internet through wireless connection.

4. Keyboard

The keyboard I have chosen is Microsoft Natural Ergonomic Keyboard 400 the cost is $60. This is used to type letters, number, and symbols in the computer. It can act as a mechanical levers or electronic switches.

5. Mouse

The mouse I have chosen is LOGITECH Wireless Mouse M305 Black and the cost is $60. This is used as pointing device that functions by detecting two-dimensional motion relative to its supporting surface.