PAWAN KUMAR COMPUTER LAB INSTRUCTOR GOVT. POLYTECHNIC MEHAM(ROHTAK) Computer Shop PAWAN KUMAR COMPUTER LAB INSTRUCTOR GOVT. POLYTECHNIC MEHAM(ROHTAK)

Types of Computers Supercomputers...are used to process very large amounts of information including processing information to predict hurricanes, satellite images and navigation, and process military war scenarios. Mainframes...are used by government and businesses to process very large amounts of information. Mini-Computers...are similar to mainframes...they are used by business and government to process large amounts of information. Personal Computers (PC)…

Types of Computers Personal Computers (Continued) Personal Computers...also known as PC’s...are smaller and less powerful than the others. They are used in homes, schools, and small businesses.

Types of Computers There are 3 main types of PCs Desktop Portable (Notebook/Laptop) When portable (notebook/laptop) computers were first created they were HUGE. They weighed around 100 lbs., and were carried in a large luggage suitcase. The creators of the portable (notebook/laptop) computer dreamed that one day it would be the size a notebook or pocket dictionary. With today’s technology, we have been able to accomplish this goal and more.. Hand-Held

Networks A network is a group of computers that share information and hardware. The computers are connected together using copper phone wires, fiber optic cables, or radio waves. Our computers are on a network here at school...Look under the table and see the blue wires that connect your computer to the network. The internet is many networks around the world that are all connected together to make 1 huge network.

Parts of a Computer There are two basic parts that make up a computer... Hardware Software

Hardware Hardware is basically anything that you can touch with your fingers. Computer Case CPU (central processing unit...Pentium chip) Monitor Keyboard & Mouse Disk Drive, Zip Drive, CD-ROM, DVD, Hard Drive Memory (RAM) Speakers Printer

Hardware (Continued) There are three types/categories of hardware 1. Input Devices 2. Output Devices 3. Storage Devices

Input Devices Input basically means getting data into the computer to be processed. Keyboard, Mouse, Trackball, Touch Pad Light Pen, Laser Scanner, Pointing Stick Touch Screen, Bar Code Reader, Scanner Microphone, Joystick

Output Devices Output basically means getting data out of the computer. Monitor Printer Speakers Headphones Modem Fax

Storage Devices Storage devices are both input and output devices in one. A storage device is a place to keep data that has been processed so that it can be retrieved at a later time to be used again. Hard Disk Floppy Disk CD’s, DVD’s Magnetic Tape Flash Memory, Jump Drive

Software Software is the programs and applications that tell the computer what to do and how to look. Computer programmers write the codes/instructions that make-up software applications/programs. HTML is a type of computer programming language that allows programmers to make web pages. The next 2 slides show what HTML codes look like and the web page the codes produce.

Two Types of Software Application Software Operating System Software

Operating System Software Directs all the activities and sets all the rules for how the hardware and software will work together. Examples would be: DOS, Windows 95, 98, ME, NT, XP, Vista, Windows 7 Unix, Linux, MAC system OS 6,7,8,9,10

Command Line Operating Systems DOS is an example of a command line operating system. On the next slide, Notice that there are no: Icons (pictures) Colors Mouse Pointer Buttons You have to memorize commands in order to use this text based operating system.

Operating Systems: GUI GUI stands for Graphical User Interface Uses pictures (icons) to represent files, folders, disk drives, modems, printers, etc. GUI’s were created to make using a computer easier, more interesting, non-threatening to inexperienced users. A mouse allows users to point at something and click to make it work. With command line you have to have all of the commands to make your programs work. Here is an example of a GUI

Application Software Programs that work with operating system software to help the computer to do specific types of work.

Application Software There are six basic types of application software...

Application Software 1. Business software: word processors, spreadsheets, and database programs. 2. Communication software: allows computers to communicate with other computers: fax software, Novell NetWare, AOL, Modem Software. 3. Graphics software: software that allows users to create and manipulate graphics...Photoshop, Print Shop, etc.

Application Software 4. Education and Reference software: Programs that help teach new material and ideas, and programs that can be used to find information...Encarta, Worldbook Encyclopedia, Jumpstart Kindergarten, MicroType. 5. Entertainment and Leisure software...Warcraft, Age of Empires, Barbie Design Center, Mrs. Pacman, Solitair 6. Integrated software: Combines several types of software into one program or package...Quicken (Spreadsheet/data base/communications/reference) or Print Shop (Graphics/Word processor).

Software

Printer its types, working and usefulness

Printers Impact Printers Non-Impact Printers Inkjet Laser Daisy wheel Thermal Laser Daisy wheel Dot- Matrix

What is a printer? An external hardware device responsible for taking computer data and generating a hard copy of that data. Printers are one of the most commonly used peripherals and they print text and still images on the paper.

“Factors affecting print quality” (1) DPI: It is a measurement of printer’s resolution indicating how many ink dots can be placed by the printer in one square inch. The higher the DPI, the sharper is image. (2) Type of printer: Each type of printer has its own capabilities of printing. Some types of printers produce high quality print while other produce low quality print. (3) Print Mode: The printing mode may also affect the quality. For example the draft mode increases the print rate but quality is reduced. (4) Toner: The quality and amount of toner also affects print quality.

“Impact Printer” These printers have a mechanism that touches the paper to create an image. These printers work by banging a print head containing a number of metal pins which strike an inked ribbon placed between the print head and the paper. An impact printer showing details of print head.sss

“Non-Impact Printers” These printers create an image on the print medium without the use of force. They don’t touch the paper while creating an image. Non-impact printers are much quieter than impact printers as they don’t strike the paper. A non-impact printer

“Dot Matrix Printer” The term dot matrix refers to the process of placing dots to form an image. Its speed is usually 30 to 550 characters per second (cps). This is the cheapest and the most noisy printer and has a low print quality. Dot Matrix were 1st introduced by Centronics in 1970.

“Advantages/Dis-advantages of Dot-Matrix” (1) In-expensive. (2) Low per page cost. (3) Energy efficient. Dis-advantages: (1) Noisy (2) Low resolution (3) Limited fonts flexibility (4) Poor quality graphics output.

“Daisy Wheel Printer” A daisy wheel printer is basically an impact printer consisting of a wheel and attached extensions on which molded characters are mounted. A daisy wheel printer produces letter quality print and it can’t produce graphics output.

“Ink-Jet Printer” It is a non-impact printer producing a high quality print. A standard Inkjet printer has a resolution of 300dpi. Newer models have further improved dpi. Inkjet printers were introduced in the later half of 1980s and are very popular owing to their extra-ordinary performance.

How Inkjet Printer works? (1) Print head having four ink cartridges moves . (2) Software instructs where to apply dots of ink, which color and what quantity to use. Color cartridge showing inkjet nozzles.

Advantages/ Dis-advantages (1) High resolution output. (2) Energy efficient. (3) Many options to select. Dis-advantages: (1) Expensive. (2) Special paper required for higher resolution output. (3) Time consuming in case of graphics printing.

Thermal Printer Thermal printers are in-expensive printers mostly used in fax machines. The Thermal printers are further classified into two types. (1) Electro thermal printers: (2) Thermal Wax printers: A fax machine using a thermal printer

“Laser Printer” Laser printers use very advanced technology and produce a high quality output. Laser printers can also produce high quality graphics images. Resolution is 600 to 1200dpi.

“Multi-function printer” A multi function printer abbreviated as MFP is an all purpose device that prints, faxes, copies and scans. A single multi function printer can replace several bulky devices. These printers use inkjet technology and provide high quality print but at slow speed.

“Plotter” A large scale printer which is very accurate in producing engineering drawings and architectural blueprints. Two types of plotters are flatbed and drum. Flatbed plotters are horizontally aligned while drum plotters are vertically positioned.

“Printers for different users” To choose a printer from a printer’s family following considerations are to be made. (1) What’s the budget? (2) Is color needed or just black& white? (3) What is the Volume of the output? (4) How important is the quality of the output? (5) What special features are needed? (6) Is the printer is to be used by a single user or a whole network?

“Printer for Home users” For home users, the quality of the print and the price of the printer both matter. So a better choice in such case is a portable color Inkjet printer. If the budget of the user is good enough then the best choice is a personal laser printer which enhances both the speed and quality of the print.

“Small and medium offices” For small and medium scale offices a better option is a multi-function printer which is an integrated device fulfilling various requirement of the office. For better output, a laser printer is the best choice.

“Printers for banks, large business organizations and companies” In banks, large size business environments and companies printers with networking capabilities should be preferred which can increase productivity and reduce the cost without compromising on the quality. Of course laser printer is quite suitable choice but multi-functional printer and inkjet printer can also play vital role.

Ports, Cables and Connectors

ports: Serial ports Considered to be one of the most basic external connections to a computer, the serial port has been an integral part of most computers for more than 20 years. Although many of the newer systems have done away with the serial port completely in favour of USB connections, most modems still use the serial port, as do some printers, PDAs and digital cameras. Few computers have more than two serial ports.

Ports: Ethernet ports An Ethernet port is an opening on computer network equipment that Ethernet cables plug into. These ports are alternatively called jacks or sockets. Ethernet ports accept cables with RJ-45 connectors.

Ports: USB ports Just about any computer that you buy today comes with one or more Universal Serial Bus connectors on the back. These USB connectors let you attach everything from mice to printers to your computer quickly and easily. The operating system supports USB as well, so the installation of the device drivers is quick and easy, too. Compared to other ways of connecting devices to your computer (including parallel ports, serial ports and special cards that you install inside the computer's case), USB devices are incredibly simple!

Cables ALL KINDS OF CABLES Power Cable Desktop computers typically use a universal power cord for power, while laptops use power adapters, often made to the specifications of the manufacture. VGA and DVI VGA and DVI cables use a series of pins to transfer video signals between devices, such as a monitor and the computer. VGA is analog, and DVI is digital. IDE and SATA IDE and SATA cables transfer data between the computer's internal components and the motherboard. The cables are pretty much the same as far as speed is concerned. USB and FireWire USB and FireWire cables allow peripherals to connect to your computer and transfer data at high speeds. FireWire cables can send and receive data at the same time, while USB cables cannot. Ethernet Ethernet cables are used to join two network devices. The cable contains four thin wires that allow data to be transferred at high speeds between the devices in the form of a series of electrical pulses.

Cables: power cord The power cord that connects the air conditioner to the wall outlet may become worn and fail to supply electricity to the unit. To check the cord, remove the control panel. Unscrew the cord terminals and then attach a test wire across the bare lead wires. Hook the clips of a volt-ohm-millimetre (VOM) set to the RX1 scale to the prongs of the cord's plug. If the meter reads zero, the cord is functioning. If the meter reads higher than zero, replace the cord.

Connectors The part of a cable that plugs into a port or interface to connect one device to another. Most connectors are either male (containing one or more exposed pins) or female (containing holes in which the male connector can be inserted).

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