IBM Computer, Laptops and Servers

• that someone else has already written that tells the computer what to do. laptop battery

Ultimately, to get a computer to do something useful, you (or somebody else) must write a program. A program does nothing more than tell the computer how to accept some type of input, manipulate that input, and spit it back out again in some form that humans find useful. Table 1 lists some common types of programs, the types of input that they accept, and the output that they produce. Table 1 Input and Output for Various Programs thinkpad

Type of Program Input What the Program Does Output

Word processor Characters you type from the keyboard Formats the text; corrects spelling Displays and prints neatly organized text Game Keystrokes or joystick movements Calculates how fast and far to move a cartoon figure on-screen Moves a cartoon figure on-screen microsoft

Stock-market predictor Current and past prices for stocks Tries to recognize trends in a stock s price fluctuations Predicts the future price of a stock Missile guidance program Current location of the missile and the target Calculates how to make the missile s location and the target s location coincide Corrects the trajectory so that it stays aimed at the target Optical character recognition (OCR) laptop computers

Text from a scanner Recognizes shapes of characters Converts scanned text into a text file that a word processor can edit Web browser HyperText Markup Language (HTML) codes on other computers Converts the HTML codes into text and graphics Displays Web pages on-screen laptop computer

Programming is problem-solving

Essentially, a program tells the computer how to solve a specific problem. Because the world is full of problems, the number and variety of programs that people can write for computers is practically endless. desktop computer

But to tell a computer how to solve one big problem, you usually must tell the computer how to solve a bunch of little problems that make up the bigger problem. If you want to make your own video game, for example, you need to solve some of the following problems: notebooks

• Determine how far to move a cartoon figure (such as a car, a spaceship, or a man) on-screen as the user moves a joystick. lenovo

• Detect whether the cartoon figure bumps into a wall, falls off a cliff, or runs into another cartoon figure on-screen. hard drive

• Make sure that the cartoon figure doesn t make any illegal moves, such as walking through a wall. travelstar

• Draw the terrain surrounding the cartoon figure and make sure that if the cartoon figure walks behind an object such as a tree, the tree realistically blocks the figure from sight. gateway

• Determine whether bullets that another cartoon figure fires are hitting the player s cartoon figure. If so, determine the amount of damage, how it affects the movement of the damaged cartoon figure, and how the damage appears on-screen. laptop parts

The simpler the problem is that you need to solve, the more easily you can write a program that tells the computer how to work. A program that displays a simple Ping-Pong game with two stick paddles and a ball is much easier to write than a program that displays World War II fighter airplanes firing machine guns and dropping bombs on moving tanks while dodging anti-aircraft fire. software

Programming isn t difficult; it s just time-consuming

Programming really isn t that difficult or mysterious. If you can write step-by-step instructions directing someone to your house, you can write a program. The hardest part about programming is identifying all the little problems that make up the big problem that you re trying to solve. Because computers are completely stupid, you need to tell them how to do everything. If you re giving a friend instructions to get to your house, for example, you may write down the following information: hard drives

1. Go south on Highway I-5. 2. Get off at the Sweetwater Road exit. 3. Turn right at the light. 4. Turn left into the second driveway. Of course, if you try giving these instructions to a computer, the computer will get confused and wants to know the following additional information: 1. Where do I start and exactly how far south do I drive down Highway I-5 2. How do I recognize the Sweetwater Road exit, and how do I get off at this exit electronics

3. After I turn right at the light, how far to the right do I turn, and do you mean the traffic light or the streetlight on the corner 4. After I turn left into the second driveway, what do I do next Park the car Honk the horn Gun the engine and accelerate through your garage door You need to tell computers how to do everything, which can make giving them instructions as aggravating and frustrating as telling children what to do. Unless you specify everything that you want the computer to do and exactly how to do it, the computer just plain won t do what you want it to do. canon

Related Articles Polishing Your Development Tools for Cocoa Programming Before You Write Your Program The Technical Details of Writing a Program The Life Cycle of a Typical Computer Program Enhancing iLife with AppleScript Related Titles PHP MySQL Web Development All-in-One Desk Reference For Dummies desktop pc

Before You Write Your Program - For Dummies Beginning Programming For Dummies, 4th Edition Before You Write Your Program Adapted From: Beginning Programming For Dummies, 4th Edition Printer-ready version

Design your program before you start writing it. That way you don t waste time writing a program that doesn t work or that solves the wrong problem and isn t worth trying to salvage afterward. By planning ahead of time, you increase the odds that your program actually works and performs the task that you want. desktop computers

The following four items are crucial to consider in designing any program: think pad

• The problem:

  What problem does your program solve If you can t clearly state what your program does, you won t know how to design it. repair

• The user:

  Who s going to use your program data recovery

• The target computer:

  Which computer do people need to run your program Is it a Windows computer, a Macintosh, a mainframe, a computer running Linux, a handheld Palm or Pocket PC, or a supercomputer cisco

• You:

  Are you going to write the entire thing yourself or get help from others If you re going to get others to help you, which parts of the program are they going to write keyboard

Every program solves a problem. A tax return program solves the problem of organizing and filing your taxes. A word processor solves the problem of writing, editing, formatting, and printing text. Even a video game solves the problem of keeping people amused. monitor

A program is only as useful as the problem it solves. Most programs simplify and automate an existing problem, such as a money management program that simplifies organizing and paying bills instead of using paper and an adding machine. The goal of any program is to make a specific task faster, easier, and more convenient. The only way reach that goal is to identify what task your program is trying to solve in the first place. desktop

The program s users

If you re the only person who s going to use your program, you can pretty much make your program look and act any way you want, just as long as you know how to make it work. But if you plan to give or sell your program to others, you need to know who s going to use it. infosys

Knowing your program s typical user is critical. If users don t like your program for any reason, they re unlikely to use it. Whether the program actually works is often irrelevant. By designing your program with the user in mind, you increase the odds that people use your program and (you hope) buy a copy for themselves. Even if you write a program that works perfectly, users still may ignore it because they don t like the way it looks, they don t understand how to give it commands, it doesn t work the same way as the old program they currently use, the colors don t look right to them, and so on. The goal is to make your program meet your users needs, no matter how weird, bizarre, or illogical they may seem (the needs not the users). refurbished laptops

The target computer

After you identify the user, you need to know what type of computer the user intends to run the program on. The type of computer that your program runs on can determine which computer languages you can use, the hardware that your program can expect to find, and even the maximum size of your program. wipro

If you re writing a program to run on a Macintosh, for example, your program can take advantage of sound, color graphics, a large hard drive, and plenty of memory. You may need to rewrite that same program drastically, however, to run it on a smart phone with its limited sound capability, much simpler color graphics, and limited amount of memory and storage space. lap top

If you can copy and run your program on another computer with little or no modification, your program is considered portable. The computer language that you use to write your program can determine its portability. That s why so many people use C/C++ C and C++ programs tend to be more portable than other programming languages. refurbished

Your programming skill

When designing any program, consider your programming skill. You may get a great idea for a program, but if you re a beginner with little experience, writing your program may take a long time if you don t give up out of frustration first. memory

Your programming skill and experience also determine the programming language that you choose. Experienced programmers may think nothing about writing entire programs in C or C++. But novices may need to spend a long time studying C and C++ before writing their programs, or they may choose an easier programming language, such as BASIC. intel

Some novices take the time to learn difficult languages, such as C/C++, and then go off and write their program. Others take an easier approach and choose a simpler language such as Visual Basic so they can create (and market) their programs right away. Don t be afraid to tackle a heavy-duty language such as C/C++, but don t be afraid to use a simpler language such as Visual Basic either. The important goal is to finish your program so you can start using it and (possibly) start selling it to others. as400

Many programmers create their programs by using a language such as Visual Basic and then later hire more experienced programmers to rewrite their programs in a more complex language such as C/C++, which can make the program faster and more efficient. averatec

The Technical Details of Writing a Program - For Dummies Beginning Programming For Dummies, 4th Edition The Technical Details of Writing a Program Adapted From: Beginning Programming For Dummies, 4th Edition Printer-ready version

Few people create programs overnight. Instead, most programs evolve over time. Because the process of actually typing programming commands can prove so tedious, time-consuming, and error-prone, programmers try to avoid actually writing their programs until they re absolutely sure that they know what they re doing. hardware

Prototyping

To make sure that they don t spend months (or years) writing a program that doesn t work right or that solves the wrong problem, programmers often prototype their programs first. Just as architects often build cardboard or plastic models of skyscrapers before a construction crew starts welding I-beams together, programmers create mock-ups (prototypes) of their programs first. dual xeon

A prototype usually shows the user interface of the program, such as windows, pull-down menus, and dialog boxes. The prototype may look like an actual program, but clicking menus doesn t do anything. The whole idea of the prototype is to show what the program looks like and how it acts, without taking the time to write commands to make the program actually work. storage

After the programmer is happy with the way the prototype looks, he or she can proceed, using the prototype as a guideline toward completing the final program. Many programmers use RAD languages like Visual Basic to create prototypes quickly. After you use Visual Basic to create a prototype that shows how your user interface works, you can start adding actual commands to later turn your prototype into an honest-to-goodness working program. seagate

Choosing a programming language

After you refine your prototype until it shows you exactly how your program will look and act, the next step is choosing a programming language to use. You can write any program by using any programming language. The trick is that some languages make writing certain types of programs easier than others. The choice of a programming language to use can pit people against one another in much the same way that religion and politics do. Although you can t find a single perfect programming language to use for all occasions, you may want to consider a variety of programming languages. Ultimately, no one cares what language you use as long as your program works. computer sales

Defining how the program should work

After choosing a specific programming language, don t start typing commands into your computer just yet. Just as programmers create mock-ups (prototypes) of their program s user interface, they often create mock-up instructions that describe exactly how a program works. These mock-up instructions are known as pseudocode. computer hardware

If you need to write a program that guides a nuclear missile to another city to wipe out all signs of life within a 100-mile radius, your pseudocode may look as follows: 1. Get the target s coordinates. 2. Get the missile s current coordinates. 3. Calculate a trajectory so the missile hits the target. 4. Detonate the nuclear warhead. By using pseudocode, you can detect flaws in your logic before you start writing your program places where the logic behind your program gets buried beneath the complexity of a specific programming language s syntax. printers

In the preceding example, you can see that each pseudocode instruction needs further refining before you can start writing your program. You can t just tell a computer, Get the target s coordinates, because the computer wants to know, Exactly how do I get the target s coordinates So rewriting the preceding pseudocode may look as follows: technology

Have a missile technician type the target coordinates. Make sure that the target coordinates are valid. Store the target coordinates in memory. You can refine the instructions even further to specify how the computer works in more detail, as follows: a. Have a missile technician type the target coordinates. b. Make sure that the target coordinates are valid: 1) Make sure that the target coordinates are complete. 2) Check to make sure that the target coordinates are within the missile s range. 3) Make sure that the target coordinates don t accidentally aim the missile at friendly territories. mainframe

c. Store the target coordinates in memory. When programmers define the general tasks that a program needs to accomplish and then refine each step in greater detail, they say that they re doing a top-down design. In other words, they start at the top (with the general tasks that the program needs to do) and then work their way down, defining each task in greater detail until the pseudocode describes every possible step that the computer must go through. samsung

Writing pseudocode can prove to be time-consuming. But the alternative is to start writing a program with no planning whatsoever, which is like hopping in your car and driving north and then wondering why you never seem to wind up in Florida. computer repair

Pseudocode is a tool that you can use to outline the structure of your program so that you can see all the possible data that the computer needs to accomplish a given task. The idea is to use English (or whatever language you understand best) to describe the computer s step-by-step actions so that you can use the pseudocode as a map for writing the actual program in whatever language (C/C++, FORTRAN, Pascal, Java, and so on) that you choose. used computers

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Choosing Your Wireless Access Point - For Dummies Wi-Fi Home Networking Just the Steps For Dummies Choosing Your Wireless Access Point Adapted From: Wi-Fi Home Networking Just the Steps For Dummies Printer-ready version

If you want to do wireless networking, your first step is to install a wireless access point. A wireless access point (WAP) gives wireless devices such as laptops, cameras, PDAs, and printers access to a network. The network may include other devices that are connected by Ethernet cables, or the network may consist entirely of wireless connections. Whatever type of network you need, your first step in setting up a wireless network is to buy and configure a WAP. digital cameras

4. Determine which Wi-Fi standards your WAP needs to support. The 802.11g standard is faster than 802.11b, and 802.11g wireless access points are backwards-compatible with 802.11b devices. If you also have 802.11a gear, you ll need a wireless access point that supports the 802.11a standard. Related Articles Logging into Your Access Point the First Time Setting Up the DHCP Server in Your Router desktops

Configuring a DHCP Client on a Windows PC or Mac Installing an Internal Wi-Fi Card Installing an External Wi-Fi Adapter

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Choosing a Network Access Mode and Finding a Wireless Network - For Dummies Wi-Fi Home Networking Just the Steps For Dummies Choosing a Network Access Mode and Finding a Wireless Network Adapted From: Wi-Fi Home Networking Just the Steps For Dummies Printer-ready version

You can choose between three network access modes when locating available Wi-Fi networks within range of your computer. Each network access mode offers a different level of security. hosting

After you ve connected to a network, the Wireless Network Connection window enables you to manage your network connections. Using this window you can connect or disconnect from networks, or change the order of preferred networks when more than one is available. netfinity

Choosing a network access mode

Follow these steps to choose a network access mode: 1. Double-click the wireless connection icon in the Windows system tray (in the lower-right corner of the screen). If you don t see a wireless connection icon in the system tray, choose Start -- All Programs -- Accessories -- Communications -- Network Connections. Right-click your wireless connection and choose Properties. Select the Show Icon in Notification Area When Connected check box and click OK. internet

2. In the Wireless Network Connection Status dialog box, click the Properties button. 3. In the Wireless Network Connection Properties dialog box, click the Wireless Networks tab. 4. Click the Advanced button to open the Advanced dialog box. 5. Choose a network access mode: Any Available Network (Access Point Preferred): The computer tries to connect to any wireless network that is detected. cheap computer

Access Point (Infrastructure) Networks Only: The computer tries to connect to networks using a wireless access point. This setting gives you more security, especially at Wi-Fi hotspots. Computer-to-Computer (Ad Hoc) Networks Only: The computer tries to connect to other computers, called ad hoc networking. 6. If you want to automatically log on to any available wireless network, select the Automatically Connect to Non-Preferred Networks check box. digital camera

Automatically logging on to any available network could leave your computer vulnerable to unknown and untrusted networks. Do not enable this option if your computer contains sensitive or personal information. printer

7. Click Close to close the Advanced dialog box and click OK to close all remaining dialog boxes. xseries

Searching for wireless networks

Use these steps to search for a wireless network within range of your computer: 1. Double-click the wireless connection icon in the Windows system tray. 2. In the Wireless Network Connection Status dialog box, click the View Wireless Networks button. maxtor

3. In the resulting Wireless Network Connection window, click Refresh Network List in the Network Tasks menu on the left side of the screen. Related Articles Sharing Folders on Wi-Fi Networks Creating a User Account on Your Wi-Fi Network Logging into a Windows PC from a Mac (and Vice Versa) Special Wi-Fi Considerations for Macs Configuring WEP or WPA Encryption on a Networked Mac data storage

Determining the Level of Wi-Fi Security You Need - For Dummies Wi-Fi Home Networking Just the Steps For Dummies Determining the Level of Wi-Fi Security You Need Adapted From: Wi-Fi Home Networking Just the Steps For Dummies Printer-ready version

The convenience of Wi-Fi (Wireless Fidelity) networks brings with it a new security threat. Anyone within broadcast range of your wireless network signal neighbors, passers-by can access your network. After they have access to the network, they can steal your Internet bandwidth, view your sensitive computer files, and even damage your software and operating system. hitachi

No matter where your network is located, you should take some basic precautions to keep it secure: 1. Decide whether or not you want others to be able to easily use your Wi-Fi network periodically. If you want to create a hotspot that friends or associates can use, you will want to use minimal security so that others can easily access it. 2. Walk around your building, property, and general area with your handheld PC or laptop to measure the range of your Wi-Fi signal in different areas (see Figure 1). rational

Figure 1:

A weak signal. 3. Evaluate the proximity of potential threats. 4. Find out what your equipment supports. This router supports several encryption technologies including: WEP (Wireless Encryption Protocol): WEP is supported by virtually all Wi-Fi devices. Unfortunately WEP is easily defeated by widely available hacking programs. WPA (Wi-Fi Protected Access): WPA is vastly superior to WEP, but it requires a special RADIUS server, which most home networks don t have. websphere

WPA-PSK (WPA Pre-Shared Key): This option is a form of WPA that does not require a RADIUS server and is the best choice for home networks. WPA-PSK is also called WPA Personal. Some older devices don t support WPA or WPA-PSK. battery

5. Routinely check for Wi-Fi intrusions. Related Articles Considering Your WEP Keys Enhancing Security with WPA-PSK Setting Up a Third-Party Firewall Performing Firewall Maintenance Blocking Unauthorized Users to Your Wi-Fi Devices Related Titles Wi-Fi Home Networking Just the Steps For Dummies Firewalls For Dummies, 2nd Edition it support

Setting Up a Third-Party Firewall - For Dummies Wi-Fi Home Networking Just the Steps For Dummies Setting Up a Third-Party Firewall Adapted From: Wi-Fi Home Networking Just the Steps For Dummies Printer-ready version

You should only run one software firewall on a computer. If you have a third-party firewall program such as Norton Internet Security, ZoneAlarm, or a similar program, you may want to disable the Windows Firewall and use the more powerful third-party program instead. western digital

Many programs now market themselves as antivirus and Internet security programs. A program that is marketed as an Internet security program should include a firewall feature. Follow these steps to set up a third-party firewall on your home network: 1. Open the Windows Firewall controls and select the Off radio button. The Windows Firewall is likely to conflict with third-party firewall programs, thus preventing you from accessing the Internet. music

2. Install the third-party firewall in accordance with the instructions provided by the program s publisher. 3. Open the firewall s control panel by double-clicking its icon in the Windows system tray. 4. In the security program s control panel, locate the firewall controls. Make sure that the firewall is enabled. The firewall controls may be labeled Personal Firewall and may be within a subcategory of general network controls. networks

5. If the program offers security profiles, choose the profile that seems to best describe your network (see Figure 1). Figure 1: Locate the Network Security controls. 6. Choose a profile and then click Edit. These steps are for the Trend Micro security program shown in Figure 1, but most security programs should let you review and edit settings for the various security profiles that are available. toner

7. In the profile settings that appear, check the security level for the profile (see Figure 2). Figure 2: Check your firewall s security level. 8. Close the firewall program and save your settings. Make sure that when you close the program, the program s icon is still in the Windows system tray. If the icon is present, the program is still running. To update the firewall, right-click the firewall program s icon in the Windows system tray and choose Update Components. Follow the on-screen instructions to download and install updates. Most firewall programs automatically check for updates on a regular basis; if it has been a couple of days since you saw an update being performed, perform a manual update. cheap laptops

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Performing Firewall Maintenance - For Dummies Wi-Fi Home Networking Just the Steps For Dummies Performing Firewall Maintenance Adapted From: Wi-Fi Home Networking Just the Steps For Dummies Printer-ready version

The risk of Internet intrusion is higher if you have an always-on broadband Internet connection, such as DSL or cable. Internet intrusion can come from down the block or halfway around the world. brother

After you ve set up a firewall for your home network, you should perform routine tasks to maintain the firewall. To update the firewall, right-click the firewall program s icon in the Windows system tray and choose Update Components. Follow the on-screen instructions to download and install updates. netvista

Halting network traffic

If your computer has a lot of hard drive activity but no programs are running, and your Internet connection is flowing a lot of data but no one is online, activate the Halt Internet Traffic command. If the hard drive activity or connection activity suddenly stops, then it is likely that your computer was being attacked. camera

Use these steps to halt network traffic: 1. Right-click the Windows system tray icon for your Internet security program. 2. In the context menu, choose Halt Internet Traffic. Traffic between your computer and the Internet should be disabled. 3. Run a complete virus and Internet security scan of your computer to identify and neutralize potential threats on your computer. 4. Choose Halt Internet Traffic again to re-enable Internet traffic. You can also disable and enable traffic from directly within your security program, as shown in Figure 1. networking

Figure 1:

Reactivate your Internet connection when you believe it s safe. The Halt Internet Traffic command only works on the computer on which it is installed. Halting Internet traffic on one computer won t prevent other computers on your network from connecting with the Internet. sharp

Reviewing the firewall logs

Most activities listed in the firewall logs are harmless network functions. However, if you are having network connection difficulties, or if you have been victimized by an attack from outside your network, these logs can help you identify and troubleshoot those problems. cheap

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