Computer hardware basics notes pdf

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If so, these are likely culprits. This could be a cause of soTware problems. The Device Manager will list all of the hardware devices installed on a PC. Any device with a problem will have a warning symbol next to it, and double clicking on that device would give d e t a i l s a n d s u g g e s t e d remedies for the problem.

Some possible. This op on will check the applica ons may fail outright if the Hard disk for errors. Some mes this is desirable, some mes not. Either way, this prac ce may slow your computer down to various degrees, and with the program running all the me, may slow down the performance of your computer. Note: Please use cau on when uninstalling socware.

These cyber-threats can cause huge dilemmas to your computer. Note: Modern computers have safeguards that shut down the system if a component is overhea ng. The performance will be slow. This problem is most likely if the computer is rather old and has had a newer and more memory demanding opera ng system installed. It will reduce the performance of the computer. Check to be sure if the computer is plugged in to an AC outlet properly. It ensures that all of the system's hardware is working properly before trying to load the opera ng system.

If the computer does not pass POST, it will not boot. Tip: Make sure the computer turns on. If nothing happens no lights, no sound, no fans, etc. Check to see that all of the cards are fully pressed down into the bus connec ons, that any socketed chips are fully pressed into their sockets, and that all cable connec ons are fully a]ached. Make sure that the drive cables are a]ached correctly. Dust can cause overhea ng problems and electrical shorts. Some mes, insects will nest inside the case as well.

All of this needs to be cleaned out before you close up the case. Take precau ons to avoid inhaling excess dust, and consider using protec ve eyeware if necessary.

Some mes the hard disk will become corrupted by a user, or by a virus. Look for recent changes in your system's opera on. You may need to run an uninstaller program to remedy socware-related problems. The computer is unable to start up — If the computer does not turn on when you press the power bu]on, the following sugges ons may help you to determine why the computer will not start up.

A surge protector can be used in this case, because voltage surges can be very damaging to computers and other electrical components. Then put on the system to perform a POST. Make sure that it is connected to a power source, and also that the VGA cable is connected to the computer. The computer screen is blank If the screen is blank, the computer may not be set to display the image on the computer screen. Fixing the power outlet in such cases should help solve the issue. The function each button depends on the program.

Clicking the mouse results in selecting an option. Positioning a cursor with the mouse is easier for non-typists than pressing various key combinations. With an appropriate software, a mouse can also be used to draw pictures. The Computer mouse is of three types and two classifications. SCANNER There are a number of situations when some information picture or text is available on paper and is needed on the computer disk for further manipulation.

A scanner is used for this purpose. A scanner scans an image and transforms it into graphics. These can be edited, manipulated and combined, and then printed. Scanners are used to reproduce photographs on the computer screen.

These can be employed in training programs and in desktop publishing. Types of scanner a Flat-bed scanner or desktop scanner b Optic scanner, looks like a camera c Hand held scanner PRINTER In order to get a copy of the output for later reference, you would require a printer. Printers are capable of printing at a very high speed. Two commonly used printers are the dot-matrix printer and the laser printer.

Printers are classified on the basis of a number of parameters like, the mechanism used for printing, speed of printing, quality of output, direction of printing, and the kind of interface they have with the computer.

Printers can be broadly classified as impact and non-impact printers. Let us understand this in detail. Impact Printers Impact printers work like typewriters. The characters are printed by striking the paper i. Impact printers can again be classified as Character printers and Line printers. Character Printers Character printers print one character at a time. Examples of character printers are. In a DMP, tiny hammers or pins strike the ribbon to produce the desired characters.

The print head consists of 9x7 arrays of pins. Characters to be printed are sent one at a time to the printer. The characters printed are a series of dots. Dot- matrix printers are inexpensive but noisy. They can print both text and graphics. They can print in any language without additional hardware change. They can also be made to print in colour by changing ribbons. These printers are used everywhere to produce internal reports and memos needed by organizations.

Daisy Wheel Printer In a daisy wheel printer, each petal has a character embossed on it. A motor spins the wheel along with it. When the desired character spins to the correct position, a print hammer strikes it to produce a character. Line printers Line printers print one line at a time. Hence, line printers are generally faster than character printers. Printing speed varies from lines to lines per minute. Some of the line printers are drum printers and chain printers.

These can continuously print for a few hours. Drum printers A drum printer consists of a cylindrical drum. The characters to be printed are embossed on it. A set of print hammers one for each character in a line, are mounted in front of the drum.

A character is printed by striking the appropriate hammer against the embossed character on the surface. The drum completes one revolution to print one line. The movement of the drum and the striking of the hammer must synchronize. Otherwise, the printing will not be uniform.

As printer drums are costly they cannot be changed often. Chain Printer A chain printer has a steel band on which the characters are embossed. The band is rotated at a high speed. As the band rotates, a hammer is activated when the desired character comes in front of it. For every character there will be a hammer. Here also, the hammer movement and the chain movement must be synchronized. The main advantage of the chain printer is that its chain can be easily changed.

Thus, different fonts and scripts can be used with the same printer. Some examples of the non-impact are laser printer, thermal printer, and inkjet printer. Laser Printer Laser printers print one page at a time. Laser printers use a light beam to form images on the paper using a toner ink as the medium. Laser printers are quiet workers.

They produce very high quality output both text and graphics. They are typically used publishing. Other Non-impact printers The other types of non-impact printers are thermal printers which use heat to print characters on paper and inkjet printers which use jets of ink to print characters on paper.

These printers are not in use as much as the laser printers. It can be used to create presentation-charts, graphics, tables and high quality technical drawings. There are two types of plotters: Drum and Flat Bed plotter. Drum Plotter The paper is placed over the drum that rotates back and forth.

A carriage holding one or more pens is mounted horizontally across the drum. The carriage with the pens moves horizontally over the paper. Each pen could be filled with different colours.

This plotter has the ability to produce colour pictures. Flat Bed Plotter In flat bed plotter, the paper does not move. The carriage holding the pens should provide all motions. Inkjet plotters can also produce large drawings with different colours. The system unit consists of primary storage, arithmetic-logic unit, and the control unit. The CPU interprets instructions to the computer, performs the logical and arithmetic processing operations, and causes the input and output operations to occur.

It acts like the central nervous system for all the components though; it does not process any data. These separate areas are not fixed. The size of each area varies from application to application. ON state is represented by 1 and OFF state is represented by 0.

A collection of 8 bits is known as a byte. One Kilobyte represents bytes and one Megabyte represents Kilobytes. Ram Random Access Memory RAM is the area that is used for holding the programs and their data while the computer is working with them. RAM means the memory can be read from and written to randomly. These sets of programs perform the most basic control and supervisory operations for the computer.

But the storage devices are not as fast as the CPU. Most of the time the CPU has to slow down because of these devices. A small section of the high speed RAM is used to keep frequently needed information. So, one need some storage device to store data and other information.

It should be cheap and should not lose the content when power is switched off. This storage is called as the secondary storage. All secondary storage devices act both as input and output devices. Magnetic storage media fulfils these requirements and most common storage devices are disks and tapes. Floppy Disk It is the most common storage media and it helps transferring the data from one computer to another.

Data is stored in these sectors. Each piece of data that is stored, has a track number, a sector number and side number as an address. So data can be accessed randomly from anywhere on the disk. Hence, it is also called as Random Access storage. The most significant difference between a floppy disk and a hard disk is that the hard-disk is completely sealed and is protected from dust and airborne particles. The name hard disk comes from the rigid platter that is inside the drive.

This is, often called by different names like fixed disk or Winchester disk. The hard disk comes in different shapes. Most hard disks nowadays store something close to MB. Magnetic Tapes Apart from using disks for external storage purposes, magnetic tapes are also used for storing large amount data. The magnetic tape could be a large reel or a small cassette. The tape is essentially a plastic ribbon coated with some material that can be magnetized. The data is recorded on these magnetic spots.

The data on the tape can however be read or written sequentially only. Hence, it is called as sequential access storage. The computer bus consists of two parts, the address bus and a data bus.

The data bus transfers actual data, whereas the address bus transfers information about where the data should go. VDUs can work in two different modes viz. Text mode and graphic mode. In text mode, the screen is divided into a matrix of rows and columns; each cell of the matrix is used for one character.

A typical screen has 80 character positions per line and 25 lines across the screen. In graphic mode, the screen is treated as an array of tiny dots called pixels.

The characters and pictures that appear on the screen are shown by making a drawing of these pixels. The number of dots on the screen is called as resolution. The higher the resolution the better the picture. A typical high resolution monitor has x pixels across the screen. The formation of images on the screen is handled by the Video Controller. The Video Controller along with the memory that holds the display- data are together referred to as display adaptors.

Though these details do not affect you as an end user, it completes your knowledge of the computer. System Unit It is a box like structure of the computer.

Inside this box you can find the power supply, storage device, hard disk and floppy drives, and the motherboard containing CPU and memory. It can also contain optional cards like the modem card, mouse card, video card, sound card. System unit or Main unit or Console comes in two styles.

Desktop model and Tower model. Hard disk activity indicator: this gives the information as to whether the hard disk is being accessed read from or written to or not. Power switch Depending on the model of the computer, power switch can be anywhere.

Reset switch Pressing this switch restarts your computer, your power supply. The entire design of the PC is based on this chip. The performance of CPU depends on the model, version and speed. Model Each CPU has a specific model number assigned to it.

Given below is the list of common CPUs produced by Intel Company in an increasing order of their power, speed and performance.

Speed The speed is measured in Megahertz. Higher the value, faster is the information processed by CPU. The clock provides the timing signals in the form of pulses that are used by the computer components to synchronize their work. The clock chip uses a quartz crystal. The speed of the clock is measured in MHz. Speed of Operation Speed of a computer can be assessed either in terms of the processing capacity of the microprocessor or by the speed of the computer which is measured in MIPS Million Instructions Per Second.

The Memory The internal memory of the PC is in the form of chips. The Bus Communication between the microprocessor, the memory chips, and another chips found on the motherboard is accomplished a set of wires running between them.

This set of wires is called the bus. The Ports As in human terminology, ports are used to receive and send goods. These ports could be serial or parallel. A serial port, is one where eight bits queued up and sent bit.

In the parallel port all the eight bits are transferred simultaneously. The Storage System The hard disk drive and floppy diskette drive are also mounted in the system unit. The Start-Up Process Every time a computer is switched on, it goes through a series before the user is permitted to interact with it.