Description of the different PC and Macintosh Operating Systems.

MAC computers
manufactured by Apple
run on their own operating system
The PC which all run on the Microsoft Windows operating system  eg. Windows 98 2000 XP Vista etc.
That’s it…that’s the defining difference between the two types of computers. If you’re running a computer with a Microsoft operating system
than you have a PC or if you are using any apple operating system such as Mac Os X 10.6  then you are using Mac Pc.

The Relationship between an Application program, the operating system and hardware.

Computer Hardware consists of the physical components that make up a computer. Some examples are and Microprocessor, a Hard Drive, or a Motherboard.

Computer Software consists of applications or programs that the user runs on a computer, such as a word processor or a video game.

An Operating System is a specific piece of software that allows other software to manipulate computer hardware to achieve a desired effect. Some Operating Systems are Microsoft Windows, Unix/Linux, or Apple OS

Basically the three interact as follows:

Hardware <-> Operating System <-> Software
(<-> specifies an interaction between two components.)
In addition computer hardware deal with different devices that interact into the computer software then it show the capacity and data of the applications while the operating system it is the combination of performance which spread out to access each other components.

Description of the Boot Process.

In order for a computer to successfully boot, its BIOS, operating system and hardware components must all be working properly; failure of any one of these three elements will likely result in a failed boot sequence. When the computer's power is first turned on, the CPU initializes itself, which is triggered by a series of clock ticks generated by the system clock. Part of the CPU's initialization is to look to the system's ROM BIOS for its first instruction in the startup program. The ROM BIOS stores the first instruction, which is the instruction to run the power-on self test (POST), in a predetermined memory address. POST begins by checking the BIOS chip and then tests CMOS RAM. If the POST does not detect a battery failure, it then continues to initialize the CPU, checking the inventoried hardware devices (such as the video card), secondary storage devices, such as hard drives and floppy drives, ports and other hardware devices, such as the keyboard and mouse, to ensure they are functioning properly. Once the POST has determined that all components are functioning properly and the CPU has successfully initialized, the BIOS looks for an OS to load. The BIOS typically looks to the CMOS chip to tell it where to find the OS, and in most PCs, the OS loads from the C drive on the hard drive even though the BIOS has the capability to load the OS from a floppy disk, CD or ZIP drive. The order of drives that the CMOS looks to in order to locate the OS is called the boot sequence, which can be changed by altering the CMOS setup. Looking to the appropriate boot drive, the BIOS will first encounter the boot record, which tells it where to find the beginning of the OS and the subsequent program file that will initialize the OS. Once the OS initializes, the BIOS copies its files into memory and the OS basically takes over control of the boot process. Now in control, the OS performs another inventory of the system's memory and memory availability (which the BIOS already checked) and loads the device drivers that it needs to control the peripheral devices, such as a printer, scanner, optical drive, mouse and keyboard. This is the final stage in the boot process, after which the user can access the system’s applications to perform tasks.

Key Terms to Understanding the System Boot process: Boot sequence BIOS CPU clock ticks power-on self test CMOS RAM ports keyboard peripheral devices drivers

The Functions of a Computer Operating System.

Functions Of Operating System  are:

Today most operating systems perform the following important functions:
   1. Processor management, that is, assignment of processor to different tasks being performed by the computer system.
2. Memory management, that is, allocation of main memory and other storage areas to the system programmes as well as user programmes and data.
3. Input/output management, that is, co-ordination and assignment of the different output and input device while one or more programmes are being executed.
4. File management, that is, the storage of file of various storage devices to another. It also allows all files to be easily changed and modified through the use of text editors or some other files manipulation routines.

5. Establishment and enforcement of a priority system. That is, it determines and maintains the order in which jobs are to be executed in the computer system.
6. Automatic transition from job to job as directed by special control statements.
7. Interpretation of commands and instructions.
8. Coordination and assignment of compilers, assemblers, utility programs, and other software to the various user of the computer system.
9. Facilities easy communication between the computer system and the computer operator (human). It also establishes data security and integrity.

OH+S considerations in the use of Computer Systems.

Ergonomics is the term that refers to scitific discipline concerned with design according to human needs. It looks at what kind of work you do, what equipment you use and your entire job environment. The goal of ergonomics is to find best fit between you and your job conditions.

To setup an ergonomic computer workstation, make sure that teh computer is placed on a stable working surface with adequate room for proper arrangement. It's important to choose a comfortable chair for the user to sit in. Chair should be adjusted at a fixed height provided that its comfortable and has a good backrest that provides lumbar support.

A good workstation design will allow any computer user to work in a neutral, ideal typing posture that will minimize the risk of deveoping any injury.

A good workstation setup may include:

Ergonomics keyboards and mouse

Wrist rests

Support braces/gloves

Other considerations are the following environmental conditions where computer will be used

Lighting

Ventilation

Noise Take a break!

Make sure to practice the following to help avoid strain and injury

Eye breaks every 15 minutes

Rest breaks every 30 to 60 minutes.

Exercise break every 1-2 hours.

http://EzineArticles.com/?How-to-create-the-ideal-Ergonomic-workstation-&id=1330145

Internal hardware components, cost, image and function.

Hard disk

A magnetic disk on which you can store computer data. The term hard is used to distinguish it from a soft, or floppy, disk. Hard disks hold more data and are faster than floppy disks. A hard disk, for example, can store anywhere from 10 to more than 100 gigabytes, whereas most floppies have a maximum storage capacity of 1.4 megabytes.

A single hard disk usually consists of several platters. Each platter requires two read/write heads, one for each side. All the read/write heads are attached to a single access arm so that they cannot move independently. Each platter has the same number of tracks, and a track location that cuts across all platters is called a cylinder. For example, a typical 84 megabyte hard disk for a PC might have two platters (four sides) and 1,053 cylinders.

In general, hard disks are less portable than floppies, although it is possible to buy removable hard disks.

Cost-$100

RAM

Pronounced ramm, acronym for random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.

There are two different types of RAM: DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory). The two types differ in the technology they use to hold data, with DRAM being the more common type. In terms of speed, SRAM is faster. DRAM needs to be refreshed thousands of times per second while SRAM does not need to be refreshed, which is what makes it faster than DRAM. DRAM supports access times of about 60 nanoseconds, SRAM can give access times as low as 10 nanoseconds. Despite SRAM being faster, it's not as commonly used as DRAM because it's so much more expensive. Both types of RAM are volatile, meaning that they lose their contents when the power is turned off.

In common usage, the term RAM is synonymous with main memory, the memory available to programs. For example, a computer with 8MB RAM has approximately 8 million bytes of memory that programs can use. In contrast, ROM (read-only memory) refers to special memory used to store programs that boot the computer and perform diagnostics. Most personal computers have a small amount of ROM (a few thousand bytes). In fact, both types of memory (ROM and RAM) allow random access. To be precise, therefore, RAM should be referred to as read/write RAM and ROM as read-only RAM

Cost-$102

VIDEO CARD

The video card is an expansion card that allows the computer to send graphical information to a video display device such as a monitor or projector.

Each motherboard supports only a limited range of video card formats so always check with your motherboard manufacturer before making a purchase.

Many modern computers do not have video expansion cards but instead have GPUs integrated directly onto the motherboard. This allows for a less expensive computer but also for a less powerful graphics system. This option is wise for the average business and home user not interested in advanced graphics capabilities or the latest games.

Cost-$190

Sound Card

An expansion board that enables a computer to manipulate and output sounds. Sound cards are necessary for nearly all CD-ROMs and have become commonplace on modern personal computers. Sound cards enable the computer to output sound through speakers connected to the board, to record sound input from a microphone connected to the computer, and manipulate sound stored on a disk.

Nearly all sound cards support MIDI, a standard for representing music electronically. In addition, most sound cards are Sound Blaster-compatible, which means that they can process commands written for a Sound Blaster card, the de facto standard for PC sound.

Sound cards use two basic methods to translate digital data into analog sounds:

·  FM Synthesis mimics different musical instruments according to built-in formulas.

·  Wavetable Synthesis relies on recordings of actual instruments to produce sound. Wavetable synthesis produces more accurate sound, but is also more expensive.

Cost-$97

CPU

Pronounced as separate letters it is the abbreviation for central processing unit. The CPU is the brains of the computer. Sometimes referred to simply as the central processor, but more commonly called processor, the CPU is where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system.

On large machines, CPUs require one or more printed circuit boards. On personal computers and small workstations, the CPU is housed in a single chip called a microprocessor. Since the 1970's the microprocessor class of CPUs has almost completely overtaken all other CPU implementations.

The CPU itself is an internal component of the computer. Modern CPUs are small and square and contain multiple metallic connectors or pins on the underside. The CPU is inserted directly into a CPU socket, pin side down, on the motherboard. Each motherboard will support only a specific type or range of CPU so you must check the motherboard manufacturer's specifications before attempting to replace or upgrade a CPU. Modern CPUs also have an attached heat sink and small fan that go directly on top of the CPU to help dissipate heat.

Two typical components of a CPU are the following:

• The arithmetic logic unit (ALU), which performs arithmetic and logical operations.
• The control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.

 Cost-$150

External hardware components and peripherals, cost, image and function.

Keyboard

The set of typewriter-like keys that enables you to enter data into a computer. Computer keyboards are similar to electric-typewriter keyboards but contain additional keys. The keys on computer keyboards are often classified as follows:

·  alphanumeric keys -- letters and numbers

·  punctuation keys -- comma, period, semicolon, and so on.

·  special keys -- function keys, control keys, arrow keys, Caps Lock key, and so on.

The standard layout of letters, numbers, and punctuation is known as a QWERTY keyboard because the first six keys on the top row of letters spell QWERTY. The QWERTY keyboard was designed in the 1800s for mechanical typewriters and was actually designed to slow typists down to avoid jamming the keys. Another keyboard design, which has letters positioned for speed typing, is the Dvorak keyboard.

There is no standard computer keyboard, although many manufacturers imitate the keyboards of PCs. There are actually three different PC keyboards: the original PC keyboard, with 84 keys; the AT keyboard, also with 84 keys; and the enhanced keyboard, with 101 keys. The three differ somewhat in the placement of function keys, the Control key, the Return key, and the Shift keys.

In addition to these keys, IBM keyboards contain the following keys: Page Up, Page Down, Home, End, Insert, Pause, Num Lock, Scroll Lock, Break, Caps Lock, Print Screen.

There are several different types of keyboards for the Apple Macintosh. All of them are called ADB keyboards because they connect to the Apple Desktop bus (ADB). The two main varieties of Macintosh keyboards are the standard keyboard and the extended keyboard, which has 15 additionalspecial-function keys

Cost-$20

Mouse

 

The other most often used input device is the mouse. Once again they can some in all sorts of colours and various types of connectors. Most mice on a personal computer (PC) have two buttons, while the typical mouse on an Apple Mac has only one button.

The mouse operated simply on a small weighted ball that can move two rollers. One roller determines how much vertical movement, while the other determines the horizontal movement.

One extra feature on the mouse today, that is not traditional, is the scroll wheel. It can be used to scroll up and down a document. It can even operate as a third button.

The most common connector is a PS2, the same as the keyboard. This means it is possible to connect both the keyboard and mouse in the wrong sockets. This will not harm the computer but it will not function correctly.

As with the keyboard, it is possible to get other types of connectors such as USB (Universal Serial Bus), Infra-red and Wireless. We won’t be examining these in detail.

Cost-$29.99

Monitor

Monitors are display devices external to the computer case and connect via a cable to a port on the video card. Even though the monitor sits outside the main computer housing, it is an essential part of the complete system.

Monitors come in two major types - CRT and LCD. CRT monitors look much like traditional televisions and are very deep in size. LCD monitors are much thinner while still offering equivalent, if not better, graphics quality. LCD monitors are beginning to obsolete CRT monitors due to their smaller "footprint" on the desk and decreasing price.

Most monitors range in size from 15" to 21" or more. This size is a diagonal measurement from one corner of the screen to the other.

Cost-$170

Printers

In computers, a printer is a device that accepts text and graphic output from a computer and transfers the information to paper, usually to standard size sheets of paper. Printers are sometimes sold with computers, but more frequently are purchased separately. Printers vary in size, speed, sophistication, and cost. In general, more expensive printers are used for higher-resolution color printing.
Personal computer printers can be distinguished as impact or non-impact printers. Early impact printers worked something like an automatic typewriter, with a key striking an inked impression on paper for each printed character . The dot-matrix printer was a popular low-cost personal computer printer. It's an impact printer that strikes the paper a line at a time. The best-known non-impact printers are the inkjet printer, of which several makes of low-cost color printers are an example, and the laser printer . The inkjet sprays ink from an ink cartridge at very close range to the paper as it rolls by. The laser printer uses a laser beam reflected from a mirror to attract ink (called toner ) to selected paper areas as a sheet rolls over a drum.
The four printer qualities of most interest to most users are:

• Color: Color is important for users who need to print pages for presentations or maps and other pages where color is part of the information. Color printers can also be set to print only in black-and-white. Color printers are more expensive to operate since they use two ink cartridges (one color and one black ink) that need to be replaced after a certain number of pages. Users who don't have a specific need for color and who print a lot of pages will find a black-and-white printer cheaper to operate.
• Resolution: Printer resolution (the sharpness of text and images on paper) is usually measured in dots per inch ( dpi ). Most inexpensive printers provide sufficient resolution for most purposes at 600 dpi.
• Speed: If you do much printing, the speed of the printer becomes important. Inexpensive printers print only about 3 to 6 sheets per minute. Color printing is slower. More expensive printers are much faster.
• Memory: Most printers come with a small amount of memory (for example, one megabyte ) that can be expanded by the user. Having more than the minimum amount of memory is helpful and faster when printing out pages with large images or tables with lines around them (which the printer treats as a large image).

Cost-$150

Speakers

An electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance.

Cost-$15