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Basic structure of a PC
A computer is an electronic device, operating under the control of instructions stored in its own memory unit that can accept data (input), process data arithmetically and logically, produce output from the processing, and save the results for future use (storage).
The most basic of all computers must have at least three parts:
- an input device – as simple as a keyboard
- a processing device – this is a microprocessor chip or a CPU
- an output device – as simple as a printer
The heart of every computer is the microprocessor chip (or integrated circuit) called the Central Processing Unit (CPU). The purpose of the microprocessor is to manipulate the data it receives by using a written set of instructions. Attached to the processor there must be at least one input device and one output device.
The input device accepts data from the operator, or the machine, using the computer and transmits it to the processing device.
The output device accepts the processed data from the processing device and presents it to the operator or machine in a usable form.
A computer has six basic functions:
- Storing whatever data is entered, so the data can be saved and used in future.
- Retrieving the stored data, this can then be used many times.
- Displaying the data you're working with on a screen or monitor, so you can see the actions that are taking place.
- Editing the data, allowing the user to change or alter data they are working on.
- Printing the data, allowing the user to obtain hard copy of the printed output.
- Sending and receiving data, allowing the user to transmit the information to another person anywhere in the world.
Hardware
The main component of any computer system is the hardware, that is, the parts of the computer that you can touch, including the:
- case (and the components inside the case)
- monitor
- keyboard
- mouse
- any other 'hard' devices attached to the system
The hardware heart of the computer is the microprocessor or CPU (Central Processing Unit). This silicon chip or integrated circuit is the part that does all the real work; this is the brains of the system.
Another very important hardware component is Random Access Memory (RAM). This is temporary storage space for the software currently being used and the data you are currently working with.
The six functions of the information processing cycle require specialised hardware devices:
- input devices
- output devices
- storage devices
- communication devices
Common input devices
The most common input device for a computer is the keyboard. Some other input devices include: the mouse, scanners, digital cameras and microphones.
Common output devices
The most common output devices for PCs are: monitors, printers, web cams and speakers.
In addition to input, processing, and output devices, most computers have several other important parts. One of the most important devices are storage devices - these hold data on a permanent basis.
Common storage devices
The most common storage devices are USB sticks, removable hard disk drives, floppy disks, CDs and DVDs.
Other storage devices include magnetic tape drives, zip drives, magneto optical devices, juke boxes and RAID arrays.
Common communication devices
Communication devices also help to share data with other computer systems, allowing connection to the internet and sharing of data across networks. The most common communication devices are wireless (such as Bluetooth and WiFi interfaces), modems and satellites.
Software
Software is the term used to refer to the programs which the computer needs to process data. A computer program is nothing more than a set of instructions that tell the computer what to do and how to do it.
The hardware is built to perform many different tasks; the software tells the hardware how to do each different task.
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