How culturally indispensable digital technology is today, it is ironic that computer generated art was attacked when it burst onto the scene in the early 1960. In fact, no other twentieth-century art form has elicited such a negative and hostile response. When the Computer Machine Made examines the cultural and critical response to computer art, or what we refer to today as digital art. Tracing the heated debates between art and science, the societal anxiety over nascent computer technology, and the myths and philosophies surrounding digital computation, Taylor is able to identify the destabilizing forces that shape and eventually fragment the computer art movement.
Wednesday, March 2, 2016
Wednesday, February 10, 2016
Father of the personal computer
Henry Edward RobertsHenry Edward Roberts coined the term "personal computer" and is considered to be the father of the modern personal computers after he released of the Altair 8800 on December 19, 1974. It was later published on the front cover of Popular Electronics in 1975 making it an overnight success. The computer was available as a kit for $439 or assembled for $621 and had several additional add-on such as a memory board and interface boards. By August 1975, over 5,000 Altair 8800 personal computers were sold; starting the personal computer revolution.
Who is the father of the computer?
Father of computing
Charles Babbage
There are hundreds of people who have major contributions to the field of computing. The following sections detail the primary founding fathers of computing, the computer, and the personal computer we all know and use today. Charles Babbage was considered to be the father of computing after his invention and concept of the Analytical Engine in 1837. The Analytical Engine contained an Arithmetic Logic Unit (ALU), basic flow control, and integrated memory; hailed as the first general-purpose computer concept. Unfortunately, because of funding issues, this computer was never built while Charles Babbage was alive.
Charles Babbage
A browser is an application program that provides a way to look at and interact with all the 
information on the World Wide Web. The word "browser" seems to have originated prior to the Web as a generic term for user interfaces that let you browse (navigate through and read) text files online.
Technically, a Web browser is a client program that uses HTTP (Hypertext Transfer Protocol) to make requests of Web servers throughout the Internet on behalf of the browser user. Most browsers support e-mail and the File Transfer Protocol but a Web browser is not required for those Internet protocols and more specialized client programs are more popular.The first Web browser, called World Wide Web, was created in 1990. That browser's name was changed to Nexus to avoid confusion with the developing information space known as the World Wide Web. The first Web browser with a graphical user interface was Mosaic, which appeared in 1993. Many of the user interface features in Mosaic went into Netscape Navigator. Microsoft followed with its Internet Explorer.
Computer software
Computer software
चित्रहरु कपिराइट हुनसक्छन।प्रतिक्रिया पठाउनुहोस्
Software is a program that enables a computer to perform a specific task, as opposed to the physical components of the system (hardware).
This includes application software such as a word processor, which enables a user to perform a task, and system software such as an operating system, which enables other software to run properly, by interfacing with hardware and with other software.Practical computer systems divide software into three major classes: system software, programming software and application software, although the distinction is arbitrary, and often blurred.Computer software has to be "loaded" into the computer's storage (such as a hard drive, memory, or RAM).
Once the software is loaded, the computer is able to execute the software.
Computers operate by executing the computer program.This involves passing instructions from the application software, through the system software, to the hardware which ultimately receives the instruction as machine code.Each instruction causes the computer to carry out an operation -- moving data, carrying out a computation, or altering the control flow of instructions.
Sunday, February 7, 2016
Microsoft Word
Microsoft Word is a word processor developed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS (1983), Apple Macintosh running Mac OS (1985), AT&T Unix PC (1985), Atari ST (1988), OS/2 (1989), Microsoft Windows (1989) and SCO Unix (1994). Commercial versions of Word are licensed as a standalone product or as a component of Microsoft Office, Windows RT or the discontinued Microsoft Works suite. Microsoft Word Viewer and Office Online are Freeware editions of Word with limited features.
Wednesday, February 3, 2016
How to play card game in computer?
A card game on your computer you can always just play the prepared downloaded games that typically come with all computers just go to start and click games or go to start open all your folders and find the folder labeled "games" and click on 1 of the card games like solitair and stuff.. otherwise you can always play card games online.online card games can be played at many sites I believe yahoo has card games, and also a site called "Kongregate" has many games, alot of which are card games.
What types of UPS are available?
There are three major types of UPS available in the market, each with their own advantages and cost.
Off-Line Units: Off-line units switch from the regular power source to an internal battery when there is a power drop. There is a brief delay between the time the power drops and the time the battery starts supplying power. However this downtime should be brief enough to avoid causing the computer to shut down. On-Line units are normally the cheapest UPS products available.
Line-Interactive Units: Line-interactive units add a transformer to minimise the need for an internal battery to be used with every power fluctuation. These units monitor the line voltage at all times and active the power transformer when the voltage falls below certain parameters. The battery is only ever activate when lower voltages are recorded. There is a brief delay between the time the power drops and the time the battery starts supplying power. However just like the Off-line units this downtime should be brief enough to avoid causing the computer to shut down.
How do UPS devices work?
UPS systems work by detecting decreases in the amount of electricity coming from the wall circuit and then boosting power to maintain a constant flow of electricity to the connected equipment. This power boost is achieved either from an internal transformer than enhances the electricity supply or from an internal battery that substitutes for the normal power source in the event of power failure.
What is the point in a UPS?
It is important to protect sensitive electronic equipment such as computers from fluctuations and cuts in the power as unexpected loss of power can cause permanent damage to components and data loss. A UPS will act as a surge protector, battery backup and generally “smooth” out the power your computer receives and ensure maximum stability. UPS devices are normally found attached to expensive mission critical workstations (such as graphical workstations or CAD machines) or servers where any downtime is unacceptable.
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
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.
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.
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
* 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
Sunday, January 10, 2016
Features of External Hardware Computer Components
External computer components connect to a computer system from OUTSIDE. They are not necessary for the system to function but make our experiences easier or better. We will discuss the following:
* Input Devices (used to get data into a computer)*Output Devices (used to get information out of a computer)
* Peripherals
Input Devices
Input devices are pieces of hardware that get raw data into the computer ready for processing.
Processing involves taking raw data and turning it into more useful information.
Input devices fall into two categories:
* Manual Input Devices - Need to be operated by a human to input information
* Automatic Input Devices - Can input information on their own.
* Output Devices
When inputted raw data has been processed it becomes usable information. Output devices are pieces of hardware that send this usable information out of the computer.
Some output devices send information out temporarily and some send information out permanently:
* Temporary Output Devices
* Permanent Output Devices
*Peripheral Devices
Almost all input and output devices are known as 'Peripheral devices'.
These are 'non-essential' hardware components that usually connect to the system externally.
Peripherals are called non-essential because the system can operate without them.
Where is the CPU located on the motherboard?
CPU/processor. The central processing unit (CPU), also called a processor, is located inside the computer case on the motherboard. It is sometimes called the brain of the computer, and its job is to carry out commands.
Tuesday, January 5, 2016
High level languages
A programming language such as C, FORTRAN, or Pascal that enables a programmer to write programs that are more or less independent of a particular type of computer. Such languages are considered high-level because they are closer to human languages and further from machine languages. In contrast, assembly languages are considered low-level because they are very close to machine languages.
The main advantage of high-level languages over low-level languages is that they are easier to read, write, and maintain. Ultimately, programs written in a high-level language must be translated into machine language by a compiler or interpreter.The first high-level programming languages were designed in the 1950s. Now there are dozens of different languages, including Ada, Algol, BASIC, COBOL, C, C++, FORTRAN, LISP, Pascal, and Prolog.
How to Burn a DVD From a computer?
Burn a DVD From a computer
Burning a video to a DVD is one of the primary reasons for owning a laptop with a DVD burner. The task can be intimidating for first-time users, but various DVD burning software can make the task a lot less daunting. Most laptops that have a built-in DVD burner will also come with software to assist in the task of creating DVDs. However, since the majority of laptops run on the Windows operating system, this article will focus on using Windows DVD Maker to create a DVD.
Locate Windows DVD Maker software from your start menu, under 'All Programs.'
Windows DVD Maker opening screenshot Click on the options link and select the options that you want for your DVD. Here is where you can decide what menu options you want for the DVD as well as the aspect ratio and format. The defaults are fine for most productions.
Windows DVD Maker opening screenshot Click on the options link and select the options that you want for your DVD. Here is where you can decide what menu options you want for the DVD as well as the aspect ratio and format. The defaults are fine for most productions.
Windows DVD Maker options menu screenshot
Click on 'Add Items' from the menu bar to select pictures and video for your DVD. You will notice a running time total in the left hand bottom of this window. The total alloted time for a DVD is 150 minutes using this method.
Selecting DVD content
Click to move to the next screen, where you will see that you are now ready to burn the files to a DVD. It is here that you can preview your DVD, make your menu selections add music to your slide show and even customize the menu if that is what you decide.
Windows DVD Maker menu options
Insert a blank DVD R/RW disk into the DVD R/RW drive. Click on the 'Burn' button from the final window left once you completed step four. If you do not already have a disk in the laptop's DVD drive, it will instruct you to put one in. Once the program completes the burn of video to the DVD, it will notify you that it is complete and eject the DVD.
Define function of the monitor of the computer?
Define function of the monitor of the computer
A computer monitor is a display adapter that displays information processed by the computer's video card. When a video card or graphics card converts binary information from is and 0S into images, these images are displayed onto the directly connected monitor. There are different types of monitors, including cathode ray tube (CRT) and liquid crystal displays (LCD). Monitors have display functions that include powering it on and off, controlling brightness, contrast and position, among others.
A liquid crystal displays or LCD is a type of flat panel monitor, meaning it's designed to be thin. This feature should not be confused with flat screen, meaning the computer monitor's screen is flat instead of curved. LCD refresh their screen differently than CRT monitors. An LCD screen is created by electric voltages hitting liquid crystal cells, allowing 64 different shades per cell. LCD have one resolution size, and, if a smaller resolution is adopted, a black border will appear around the re-sized resolution.
Useful programs
Useful programs
Here are some computer programs useful in understanding and implementing dissonance-based tuning and timbres. Since I usually program in the language MATLAB, most of these are MATLAB programs, although the dissonance calculating program is also available in Microsoft's version of BASIC. Morgan Thunder has also translated the dissonance measuring program into C, and updated by Prof. Frink while Mauricio Rodriguez has translated it into LISP -- thanks Morgan, Prof. Frink, and Mauricio!To calculate the dissonance of a sound with a given spectrum, use the following program, which should be placed in your MATLAB folder and called dismeasure.
The logical structure and the meaning of the variables are discussed in the section How to Calculate Dissonance Curves of the paper Relating Tuning and Timbre, which is available on-line for your browsing pleasure.
A pair of useful MATLAB programs converts from musical ratios into cents, and back again. The which should be named ratcent and centrat and placed in your MATLAB folder. As usual in MATLAB the input variables cents and ratios can be scalars or vector.
Different between hardware and software?
The beauty of a computer is that it can run a word-processing program one minute and then a photo-editing program five seconds later. In other words, although we don't really think of it this way, the computer can be reprogrammed as many times as you like. This is why programs are also called software. They're "soft" in the sense that they are not fixed: they can be changed easily. By contrast, a computer's hardware the bits and pieces from which it is made and the peripherals, like the mouse and printer, you plug into it is pretty much fixed when you buy it off the shelf. The hardware is what makes your computer powerful; the ability to run different software is what makes it flexible. That computers can do so many different jobs is what makes them so useful and that's why millions of us can no longer live without them.
What do you mean by operating system?
Suppose you're back in the late 1970, before off-the-shelf computer programs have really been invented. You want to program your computer to work as a word processor so you can bash out your first novel—which is relatively easy but will take you a few days of work. A few weeks later, you tire of writing things and decide to reprogram your machine so it'll play chess. Later still, you decide to program it to store your photo collection. Every one of these programs does different things, but they also do quite a lot of similar things too. For example, they all need to be able to read the keys pressed down on the keyboard, store things in memory and retrieve them, and display characters (or pictures) on the screen. If you were writing lots of different programs, you'd find yourself writing the same bits of programming to do these same basic operations every time. That's a bit of a programming chore, so why not simply collect together all the bits of program that do these basic functions and reuse them each time.
A typical computer architecture linking the hardware to the applications via the BIOS and the operating system.
That's the basic idea behind an operating system: it's the core software in a computer that (essentially) controls the basic chores of input, output, storage, and processing. You can think of an operating system as the "foundations" of the software in a computer that other programs (called applications) are built on top of. So a word processor and a chess game are two different applications that both rely on the operating system to carry out their basic input, output, and so on. The operating system relies on an even more fundamental piece of programming called the BIOS (Basic Input Output System), which is the link between the operating system software and the hardware. Unlike the operating system, which is the same from one computer to another, the BIOS does vary from machine to machine according to the precise hardware configuration and is usually written by the hardware manufacturer. The BIOS is not, strictly speaking, software: it's a program semi-permanently stored into one of the computer's main chips, so it's known as firmware, it is usually designed so it can be updated occasionally, however.
Photo: Typical computer architecture: You can think of a computer as a series of layers, with the hardware at the bottom, the BIOS connecting the hardware to the operating system, and the applications you actually use (such as word processors, Web browsers, and so on) running on top of that. Each of these layers is relatively independent so, for example, the same Windows operating system might run on laptops running a different BIOS, while a computer running Windows (or another operating system) can run any number of different applications.
Operating systems have another big benefit. Back in the 1970 and early 1980 virtually all computers were maddeningly different. They all ran in their own, idiosyncratic ways with fairly unique hardware (different processor chips, memory addresses, screen sizes and all the rest). Programs written for one machine (such as an Apple) usually wouldn't run on any other machine (such as an IBM) without quite extensive conversion. That was a big problem for programmers because it meant they had to rewrite all their programs each time they wanted to run them on different machines. How did operating systems help? If you have a standard operating system and you tweak it so it will work on any machine, all you have to do is write applications that work on the operating system. Then any application will work on any machine. The operating system that definitively made this breakthrough was, of course, Microsoft Windows, written by Bill Gates. It's important to note that there were earlier operating systems too. You can read more of that story in our article on the history of computers.
what is computer program?
As you can read in our long article on computer history, the first computers were gigantic calculating machines and all they ever really did was "crunch numbers": solve lengthy, difficult, or tedious mathematical problems. Today, computers work on a much wider variety of problems but they are all still, essentially, calculations. Everything a computer does, from helping you to edit a photograph you've taken with a digital camera to displaying a web page, involves manipulating numbers in one way or another.
Suppose you're looking at a digital photo you just taken in a paint or photo-editing program and you decide you want a mirror image of it in other words, flip it from left to right. You probably know that the photo is made up of millions of individual pixels colored squares arranged in a grid pattern. The computer stores each pixel as a number, so taking a digital photo is really like an instant, orderly exercise in painting by numbers! To flip a digital photo, the computer simply reverses the sequence of numbers so they run from right to left instead of left to right. Or suppose you want to make the photograph brighter. All you have to do is slide the little "brightness" icon. The computer then works through all the pixels, increasing the brightness value for each one by, say, 10 percent to make the entire image brighter. So, once again, the problem boils down to numbers and calculations.
What makes a computer different from a calculator is that it can work all by itself. You just give it your instructions (called a program) and off it goes, performing a long and complex series of operations all by itself. Back in the 1970s and 1980s, if you wanted a home computer to do almost anything at all, you had to write your own little program to do it. For example, before you could write a letter on a computer, you had to write a program that would read the letters you typed on the keyboard, store them in the memory, and display them on the screen. Writing the program usually took more time than doing whatever it was that you had originally wanted to do (writing the letter). Pretty soon, people started selling programs like word processors to save you the need to write programs yourself.
The Importance of the main() Function in C Programming
By Dan Gookin from C All-in-One Desk Reference For Dummies
All C language programs must have a main() function. It's the core of every program. It's required. The main() function doesn't really have to do anything other than be present inside your C source code. Eventually, it contains instructions that tell the computer to carry out whatever task your program is designed to do. But it's not officially required to do anything.
The basic main() function
When the operating system runs a program in C, it passes control of the computer over to that program. This is like the captain of a huge ocean liner handing you the wheel. Aside from any fears that may induce, the key point is that the operating system needs to know where inside your program the control needs to be passed. In the case of a C language program, it's the main() function that the operating system is looking for.
At a minimum, the main() function looks like this:
main() {}
Like all C language functions, first comes the function's name, main, then comes a set of parentheses, and finally comes a set of braces, also called curly braces.
If your C program contains only this line of code, you can run it. It won't do anything, but that's perfect because the program doesn't tell the computer to do anything. Even so, the operating system found the main() function and was able to pass control to that function — which did nothing but immediately return control right back to the operating system. It's a perfect, flawless program.
Dissecting the main() function
The set of parentheses after a C language function name is used to contain any arguments for the function — stuff for the function to digest. For example, in the sqrt() function, the parentheses hug a value; the function then discovers the square root of that value.
The main() function uses its parentheses to contain any information typed after the program name at the command prompt. This is useful for more advanced programming. Beginning programmers should keep in mind what those parentheses are there for, but you should first build up your understanding of C before you dive into that quagmire.
The braces are used for organization. They contain programming instructions that belong to the function. Those programming instructions are how the function carries out its task or does its thing.
By not specifying any contents, as was done for the main() function earlier, you have created what the C Lords call a dummy function — which is kind of appropriate, given that you're reading this at Dummies.com.
Note that the basic, simple main()function doesn't require a specific keyword or procedure for ending the program. In some programming languages, an END or EXIT command is required, but not in C. In the C language, the program ends when it encounters the last brace in the main() function. That's the sign that the program is done, after which control returns to the operating system.
All C language programs must have a main() function. It's the core of every program. It's required. The main() function doesn't really have to do anything other than be present inside your C source code. Eventually, it contains instructions that tell the computer to carry out whatever task your program is designed to do. But it's not officially required to do anything.
The basic main() function
When the operating system runs a program in C, it passes control of the computer over to that program. This is like the captain of a huge ocean liner handing you the wheel. Aside from any fears that may induce, the key point is that the operating system needs to know where inside your program the control needs to be passed. In the case of a C language program, it's the main() function that the operating system is looking for.
At a minimum, the main() function looks like this:
main() {}
Like all C language functions, first comes the function's name, main, then comes a set of parentheses, and finally comes a set of braces, also called curly braces.
If your C program contains only this line of code, you can run it. It won't do anything, but that's perfect because the program doesn't tell the computer to do anything. Even so, the operating system found the main() function and was able to pass control to that function — which did nothing but immediately return control right back to the operating system. It's a perfect, flawless program.
Dissecting the main() function
The set of parentheses after a C language function name is used to contain any arguments for the function — stuff for the function to digest. For example, in the sqrt() function, the parentheses hug a value; the function then discovers the square root of that value.
The main() function uses its parentheses to contain any information typed after the program name at the command prompt. This is useful for more advanced programming. Beginning programmers should keep in mind what those parentheses are there for, but you should first build up your understanding of C before you dive into that quagmire.
The braces are used for organization. They contain programming instructions that belong to the function. Those programming instructions are how the function carries out its task or does its thing.
By not specifying any contents, as was done for the main() function earlier, you have created what the C Lords call a dummy function — which is kind of appropriate, given that you're reading this at Dummies.com.
Note that the basic, simple main()function doesn't require a specific keyword or procedure for ending the program. In some programming languages, an END or EXIT command is required, but not in C. In the C language, the program ends when it encounters the last brace in the main() function. That's the sign that the program is done, after which control returns to the operating system.
Programming the ENIAC
Built in 1943-45 at the Moore School of the University of Pennsylvania for the War effort by John Mauchly and J. Presper Eckert (no relation to Columbia University's Wallace Eckert) but not delivered to the Army until just after the end of the war, the Electronic Numerical Integrator And Computer (ENIAC) was the first general-purpose electronic digital computer. It was 150 feet wide with 20 banks of flashing lights and about 300 times faster than the Mark 1 at addition. Wallace Eckert is cited in the histories as an influence on the designers, as he was for the Mark 1. These US Army photos from the archives of the ARL Technical Library show two early programmers (Gloria Ruth Gordon [Bolotsky] and Ester Gerston) at work on the ENIAC.
The ENIAC was not a stored-program computer; it is "better described as a collection of electronic adding machines and other arithmetic units, which were originally controlled by a web of large electrical cables" (David Alan Grier, IEEE Annals of the History of Computing, Jul-Sep 2004, p.2). It was programmed by a combination of plugboard wiring (shown at the top) and three "portable function tables", shown above (CLICK HERE and HERE for better views). Each function table has 1200 ten-way switches, used for entering tables of numbers. Note the IBM punches on the far right -- a bit hard to make out; better visible in this clearer but less atmospheric copy of the same photo. Franz Alt writes in Archaeology of Computers -- Reminiscences, 1945-47, Communications of the ACM, July 1972:
One of the peculiarities that distinguished ENIAC from all later computers was the way in which instructions were set up on the machine. It was similar to the plugboards of small punched-card machines, but here we had about 40 plugboards, each several feet in size. A number of wires had to be plugged for each single instruction of a problem, thousands of them each time a problem was to begin a run; and this took several days to do and many more days to check out. When that was finally accomplished, we would run the problem as long as possible, i.e. as long as we had input data, before changing over to another problem. Typically, changeovers occurred only once every few weeks.
Later, ENIAC's plugboards were permanently "microprogrammed" with a repertoire of 50-100 commonly used instructions that could be referenced from a "user program" entered as a sequence of instructions into the function-table switches. [40]
Herb Grosch says of this page [10 May 2003]:
I was roaming around the links and sublinks in the ENIAC story, and note with much interest that there were three or four castered twiddle boards [portable function tables A, B, and C], where I had always assumed only one.
I note the almost complete absence of Col.[then Major] Simon, and of Dick Clippinger, who should share with von Neumann the credit for moving from plugging to twiddling for program insertion.
I was pleased to see short reference to the IBM I/O units, which show in your and other copies of the most famous photo. I wonder if John McPherson knows how they were sold/rented/given to the Moore School --- never thought to ask him at the time. Unusual.
Bashe [4] says, "When the Army requested special card reading and punching units for an undisclosed project underway at the University of Pennsylvania, [IBM Chief Engineer James W.] Bryce and his staff coordinated IBM's response... In 1946, the instrument produced by the project was revealed as ENIAC..."
Not on your page, but in the Richie story and other Aberdeeneries there should have [been made] mention of the astronomer who taught them how to calculate trajectories by hand: Forest Ray Moulton, circa 1920 [my p.89].
That prolly wasn't intentional, but the elision of all references to the big punched card shop Cunningham ran, and to the two relay machines IBM built, certainly was. Those are what actually did firing tables, after desk calculators were overwhelmed and until the Bell machine arrived, and until ENIAC was moved in and later freed up.
Now, about the "I'm dubious ..." above. I don't think Wallace Eckert had any influence whatsoever on the designers of the ENIAC or the ASCC. Certainly in the hundreds and hundreds of hours he and I talked about those two machines, he never mentioned such, nor did Frank Hamilton, who was Number Two on the ASCC, ever hint at the latter.
A 1938 meeting between ASCC's Howard Aiken and Wallace Eckert is well known [9]. Gutzwiller [90] says that Presper Eckert (among other well-known pioneers of computing including Aiken and Vannevar Bush) got his first inspiration from Wallace Eckert's 1940 "orange book". I have not been able to pin down any evidence of direct contact between the two Eckerts. Since ENIAC was a war project (as was the Aberdeen Relay Calculator, with which Eckert was also ostensibly involved) it would not be surprising that records are not available.
The ENIAC was not a stored-program computer; it is "better described as a collection of electronic adding machines and other arithmetic units, which were originally controlled by a web of large electrical cables" (David Alan Grier, IEEE Annals of the History of Computing, Jul-Sep 2004, p.2). It was programmed by a combination of plugboard wiring (shown at the top) and three "portable function tables", shown above (CLICK HERE and HERE for better views). Each function table has 1200 ten-way switches, used for entering tables of numbers. Note the IBM punches on the far right -- a bit hard to make out; better visible in this clearer but less atmospheric copy of the same photo. Franz Alt writes in Archaeology of Computers -- Reminiscences, 1945-47, Communications of the ACM, July 1972:
One of the peculiarities that distinguished ENIAC from all later computers was the way in which instructions were set up on the machine. It was similar to the plugboards of small punched-card machines, but here we had about 40 plugboards, each several feet in size. A number of wires had to be plugged for each single instruction of a problem, thousands of them each time a problem was to begin a run; and this took several days to do and many more days to check out. When that was finally accomplished, we would run the problem as long as possible, i.e. as long as we had input data, before changing over to another problem. Typically, changeovers occurred only once every few weeks.
Later, ENIAC's plugboards were permanently "microprogrammed" with a repertoire of 50-100 commonly used instructions that could be referenced from a "user program" entered as a sequence of instructions into the function-table switches. [40]
Herb Grosch says of this page [10 May 2003]:
I was roaming around the links and sublinks in the ENIAC story, and note with much interest that there were three or four castered twiddle boards [portable function tables A, B, and C], where I had always assumed only one.
I note the almost complete absence of Col.[then Major] Simon, and of Dick Clippinger, who should share with von Neumann the credit for moving from plugging to twiddling for program insertion.
I was pleased to see short reference to the IBM I/O units, which show in your and other copies of the most famous photo. I wonder if John McPherson knows how they were sold/rented/given to the Moore School --- never thought to ask him at the time. Unusual.
Bashe [4] says, "When the Army requested special card reading and punching units for an undisclosed project underway at the University of Pennsylvania, [IBM Chief Engineer James W.] Bryce and his staff coordinated IBM's response... In 1946, the instrument produced by the project was revealed as ENIAC..."
Not on your page, but in the Richie story and other Aberdeeneries there should have [been made] mention of the astronomer who taught them how to calculate trajectories by hand: Forest Ray Moulton, circa 1920 [my p.89].
That prolly wasn't intentional, but the elision of all references to the big punched card shop Cunningham ran, and to the two relay machines IBM built, certainly was. Those are what actually did firing tables, after desk calculators were overwhelmed and until the Bell machine arrived, and until ENIAC was moved in and later freed up.
Now, about the "I'm dubious ..." above. I don't think Wallace Eckert had any influence whatsoever on the designers of the ENIAC or the ASCC. Certainly in the hundreds and hundreds of hours he and I talked about those two machines, he never mentioned such, nor did Frank Hamilton, who was Number Two on the ASCC, ever hint at the latter.
A 1938 meeting between ASCC's Howard Aiken and Wallace Eckert is well known [9]. Gutzwiller [90] says that Presper Eckert (among other well-known pioneers of computing including Aiken and Vannevar Bush) got his first inspiration from Wallace Eckert's 1940 "orange book". I have not been able to pin down any evidence of direct contact between the two Eckerts. Since ENIAC was a war project (as was the Aberdeen Relay Calculator, with which Eckert was also ostensibly involved) it would not be surprising that records are not available.
Multi function device (MFD)
A product or device that has multiple functions. An example of this might be a printer that also makes copies, faxes, and scans. Another example is a CD or DVD that might contain multiple applications on the same disk; this may be a Mac and PC version of the same software or media meant to be played on more than one platform. Also called multi function product (MFP), all-in-one.
Read more: http://www.businessdictionary.com/definition/multi-function-device-MFD.html#ixzz3wM5ABYwc.
Monday, January 4, 2016
Function of computer hardware components
A processor is the brains of any computer system. Also known as a CPU or central processing unit it is used to execute instructions that enable the operating system and application software to run on a system. A processor performs arithmetic and logical calculations in the ALU (arithmetic logical unit) and control instructions in the control unit. The processor communicates with storage devices such as the hard drive and RAM to process information used to control the operating system and applications that run on a computer system. Processors are being made smaller and faster all the time and this allows systems to carry out instructions faster and perform better. A processor in a mission critical system used in space or a medical device needs to be very powerful to carry out instructions quickly.
Processors are integrated into a computer system by placing them on the motherboard. A Motherboard is like the body of a computer system it contains a socket to house the processor and links a lot of internal components together such as RAM and graphics cards using communication buses. The have integrated controllers to enable the processor to communicate with storage devices such as HDDs and CD/DVD drives. A motherboard is a printed circuit board (PCB) and links the components using lines drawn on the circuit board. Motherboards contain expansion slots to insert RAM or graphics, sound and network cards to improve system performance. They allow a computer engineer to upgrade the RAM so that a machine runs faster. Motherboards also contain sockets to enable a computer system to communicate with external devices using USB ports, sound jacks and VDU outputs. A motherboard comes in different form factors (this is the shape and size) and you need to check if components are compatible with this form factor before purchasing them. A phone also has a motherboard which is much smaller than that used in a PC obviously. PC motherboards normally require them to be cooled to keep components running at optimal performance. This is done using fans and heat sinks.
BIOS or basic input/output system is firmware (firmware links hardware and software) built into a computer system. The BIOS is used to ensure that a system boots up correctly and all hardware components are configured to work correctly. It contains information about the hardware components connected to the system such as keyboard and mouse and enables applications installed on the system to be controlled by the hardware. The BIOS is stored in non-volatile ROM (read only memory) of a system and is configured to allow that motherboard and all connected components and peripherals to run correctly.
A power supply or PSU (power supply unit) is used to power all of the components in a computer system. The power supply runs from 120 or 240 volts mains supplied and provides 12v, 5v and sometimes 3.3v outputs to power different components. A hard drive needs a power supply to run and the PSU has a specific output connector that can be used to connect to different hard drive types. Standard connectors are ATX – you can find out more by researching the different type of connectors that power supplies have. They normally range from between £20 to £50 in price.
A fan is used in a computer system to suck hot air out of the system to make sure that it does not overheat. Most computer systems will have fans on the casing to suck the hot air out of the system. The fans are connected to the power supply. Most processors also have a fan connected to them to draw the heat away from them and ensure the operate at the best speed possible. You will hear a system that is getting hot become noisy as the fans increase in speed. Heat sinks are also used to keep systems cool. Heat sinks are made from materials that draw heat away such as aluminium and copper. Often a heat sink is placed on top of a processor to draw the heat away from it. A fan will be placed on top of the heat sink to continuously draw out the heat that the processor produces. This heat is then drawn away from the systems by fans placed on the casing. Sometimes water is used to cool systems that are prone to heating up – you can investigate this further to see how water cooling is used in gaming systems as an example.
For a computer system to run it needs a storage system to store information about the operating system and applications. Knowledge of hard drive configuration and controllers is an important skill to have when setting up a system. There are different ways to communication with HDDs (hard disk drives) such as SATA, IDE or EIDE. SATA or Serial ATA (Serial Advanced Technology Attachment) is a serial communications method that communicates over a serial cable. If your motherboard is configured with SATA then you need to buy a SATA compliant HDD. IDE (integrated drive electronics) that has the controller for the hard drive stored on the drive itself. Master/slave configuration is used when installing an additional HDD on your computer system. The master/slave hard drive configuration means that both drives can be controlled using a single cable. The IDE controllers in each HDD talk to each other to say when it is ok for the system to send or receive data to and from the storage device. If the master drive is in use it will send a message to the slave to tell it that. When the master drive is finished communicating with the system it will send a message to say that the communications are complete and the slave can go ahead and perform the required actions. This is normally configured using hardware jumpers to say with is the master and which is the slave drive.
Most computer systems use ports such as USB, parallel and serial to communicate with external devices. A USB (universal serial bus) port allows you to plugin in an external storage device such as a keyboard or mouse to connect to the motherboard and enable the user to control the system. The motherboard comes with a USB controller chip to enable the communication to take place. Parallell ports were initially used for printers and are not as common these days. They are used for devices that need a lot of communication such as a plotter used in sign writing. The have more communication lines than a serial port and therefore can send and receive more data.
In order to explain the function of computer hardware components in full it is important to consider the internal memory components of a computer system. The three main types of internal memory in a computer system are RAM, ROM and cache. RAM or random access memory is memory that linked to a processor on the motherboard. Data can be written to and read from random access memory at roughly the same speed. RAM chips are stored on separate printed circuit boards that can be plugged into a system motherboard. Applications write data to the RAM chips based on current operations. RAM is wiped when a systems shuts down. For example, if a large amount of data is copied on to the clipboard it would be stored in random access memory. If you do not clear the clipboard the information will still be available to paste in an hour or even week’s time but if the system shuts down the information will not be available to paste as the RAM will be cleared. RAM upgrades can increase system performance as more applications can be used at the same time with less impact on system resources. ROM or read only memory contains system information such as the BIOS (although some bios is stored directly on the motherboard itself). Although it is considered read only it can be configured in some sense like setting the BIOS password. ROM also stores information about the operating and other programs stored on the system. ROM does not get wiped when a system reboots. Cache memory is ram that can be accessed much quicker than regular RAM that is slotted into a motherboard on a computer system. Cache is normally stored within the CPU or on a separate cache memory chip located right beside the CPU. Cache has different levels high speed and ultra high speed. L1 or level 1 cache is normally stored on the CPU chip and is the fastest type of cache. Cache memory is used by the processor to carry out instructions more quickly as data can be accessed by the processor quicker due to the proximity of the cache and ultra high speed.
Specialised cards such as network and graphic cards are used to increase the functionality and performance of a computer system. Some motherboards come with integrated graphics meaning that the graphics driver is stored on the motherboard. For better graphical performance a specialised graphics card with increase the performance in terms of outputting a better quality and higher resolution picture from your computer system. Installing a specialised graphics card would be important for someone like a movie editor who wanted to see the full impact of high definition video when editing. A network card can be plugged into an expansion slot to enable a computer system to connect to a network. This can be an internal network or the world wide web. Again some motherboards come with integrated networking capability but installing a specialised NIC (network interface card) will increase performance in terms of connection speed etc.
