Wednesday, February 3, 2016

Printer Computing

The world's first computer printer was a 19th-century mechanically driven apparatus invented by Charles Babbage for his difference engine.This system used a series of metal rods with characters printed on them and stuck a roll of paper against the rods to print the characters. The first commercial printers generally used mechanisms from electric typewriters and Teletype machines, which operated in a similar fashion. The demand for higher speed led to the development of new systems specifically for computer use. Among the systems widely used through the 1980 were daisy wheel systems similar to typewriters, line printers that produced similar output but at much higher speed, and dot matrix systems that could mix text and graphics but produced relatively low-quality output. The plotter was used for those requiring high quality line art like blueprints.The introduction of the low-cost laser printer in 1984 with the first HP Laser Jet, and the addition of PostScript in next year's Apple Laser Writer, set off a revolution in printing known as desktop publishing. Laser printers using PostScript mixed text and graphics, like dot-matrix printers, but at quality levels formerly available only from commercial typesetting systems. By 1990, most simple printing tasks like fliers and brochures were now created on personal computers and then laser printed; expensive offset printing systems were being dumped as scrap. The HP Desk jet of 1988 offered the same advantages as laser printer in terms of flexibility, but produced somewhat lower quality output (depending on the paper) from much less expensive mechanisms.

Monday, February 1, 2016

Computer Network

What is a Computer Network? 

A computer network is a set of computers connected together for the purpose of sharing resources. The most common resource shared today is connection to the Internet. Other shared resources can include a printer or a file server. The Internet itself can be considered as a computer network.
Computer Network Defined a computer network is a set of connected computers. Computers on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wireless through radio waves. Connected computers can share resources, like access to the Internet, printers, file servers, and others. 

Types of Network Connections
Computer networks can be broken down historically into  is a technique of connecting computers. The most common topology today is a collapsed ring. This is due to the success of a network protocol called the Ethernet. This protocol, or a network language, supports the Internet, Local Area Networks, and Wide Area Networks.

Star Topology
A star topology is a design of a network where a central node extends a cable to each computer on the network. On a star network, computers are connected independently to the center of the network. If a cable is broken, the other computers can operate without problems. A star topology requires a lot of cabling.

Bus Topology
A bus topology is another type of design where a single cable connects all computers and the information intended for the last node on the network must run through each connected computer. If a cable is broken, all computers connected down the line cannot reach the network. The benefit of a bus topology is a minimal use of cabling.

Collapsed Ring Topology
A similar topology is called a ring. In this design, computers are connected via a single cable, but the end nodes also are connected to each other. In this design, the signal circulates through the network until it finds the intended recipient. If a network node is not configured properly, or it is down temporarily for another reason, the signal will make a number of attempts to find its destination.

About mouse

PC Mouse with Miniature White Figures : Stock Photo
Mouse is a national youth development nonprofit that believes in technology as a force for good. We empower all students to create with technology to solve real problems and make meaningful change in our world.Mouse opens opportunities for youth from under served communities and helps all students realize their full potential and the potential of technology to make a positive impact in their schools and communities.We are committed to increasing diversity in STEM and believe it is critical to support a diverse pool of talent to fuel the nation's future.


Computer keyboard

A computer keyboard is a typewriter-style device which uses an arrangement of buttons or keys to act as a mechanical lever or electronic switch. Following the decline of punch cards and paper tape, interaction via teleprinter style keyboards became the main input device for computers.
Computer Keyboard with Miniature White Figures : Stock Photo
A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs characters, other keys or simultaneous key presses can produce actions or execute computer commands.

Sunday, January 31, 2016

What is Computer Graphics?

The term computer graphics includes almost everything on computers that is not text or sound. Today almost every computer can do some graphics, and people have even come to expect to control their computer through icons and pictures rather than just by typing.Here in our lab at the Program of Computer Graphics, we think of computer graphics as drawing pictures on computers, also called rendering. The pictures can be photographs, drawings, movies, or simulations -- pictures of things which do not yet exist and maybe could never exist. Or they may be pictures from places we cannot see directly, such as medical images from inside your body.We spend much of our time improving the way computer pictures can simulate real world scenes. We want images on computers to not just look more realistic, but also to BE more realistic in their colors, the way objects and rooms are lighted, and the way different materials appear. We call this work "realistic image synthesis", and the following series of pictures will show some of our techniques in stages from very simple pictures through very realistic ones.

Statements in QBASIC

Statements in QBASIC

A statement (for the QBASIC) is a set of instructions written by using keywords or commands of QBASIC. Every programming language uses keywords as a statement with certain syntax. The keywords have specific meaning in the QBASIC programming. The statements are the first stored in the memory and executed only when the RUN command is given.

Different statements used in QBASIC are as follows:
CLS Statement

The CLS statement clears the screen. If you write CLS statement in the middle of the program then you cannot see the outputs generated before execution of CLS because it clears the screen.
Syntax: CLS

LET Statement

LET is an assignment statement. It is used to assign the value to a variable. LET is an optional statement i.e. without using LET statement one can assign the value to a variable. The data type must match with the variable type otherwise type mismatch error will occur.

Saturday, January 30, 2016

THE FIVE TYPES OF COMPUTERS

   TYPES OF COMPUTERS
* Mainframe  
-      first type of computer used by government and businesses
-      multiple tasks for many users simultaneously
-      Large corporations
-      Climate controlled rooms
-      Hook-up to it through personal computer
-      Examples  government agencies accessing social security numbers/info
-      National car rental company access info on anytime/where you have ever rented a car
-      Credit card companies customer service

* Supercomputer
-       Processes trillions of calculations per second
-       Weather forecasting
-       Crash testing
-       Special effects in movies
-       $100 million
-       Why do people spend this much on a computer? save lives or will make more than it cost

* Minicomputers
-        Popular in the 70 and 80
-        Small to medium size companies
-        Schools and small office companies (less than 100 people)
-        Less than $100,000
-       Now that PCs are so powerful, these are becoming OBSO.

* Personal Computers
-        Exploded in the early 80
-        Cost is always decreasing
-        Use to have a lot of types now Apple and IBM  compatible (Apple good for media)
-        Rapid processing and relatively low cost
-        Scientist, graphics, financial analyst, architects
-        $2000-$9000