Chapter 2: Running Programs

What Are Programs and Windows?

A program is a sequence of computer instructions that perform a task. Programs are stored in program files, which have the filename extension .exe or .com. When you run a program, your computer executes the instructions in the program file.

Programs can do several things at once; for example, a word processing program may be able to print one document while you edit another. One program can run several tasks or processes at the same time. Windows itself runs many tasks at the same time, including tasks that monitor the hard disk, screen, and keyboard; update the onscreen clock; and run programs on a schedule, for example. The heart of Windows is its capability to multitask, that is, to run many processes at the same time.

An application is a program that does real-world-oriented work. Word processors, spreadsheets, and databases are widely used types of applications. A systems program does computer-oriented work--an operating system like Windows itself is the most important systems program you use. Printer drivers (which control the actions of a printer) or disk scanners (which check disks for errors) are other examples of system programs. A utility is a small, simple, useful program (either a small application or a small systems program). Windows comes with many utilities, like Calculator and Notepad.

If you have user accounts on your system, you can run a program as if you logged in as another user, assuming that you know the user account's password.

Each program displays information in one or more windows--rectangular areas on the screen that display information from a running program.. Some windows are divided into sections called panes. To run more than one program at the same time, go ahead and run one program, then another, then another. The first program you run continues to run when the second program starts. Each program's window(s) can be minimized, maximized, or restored. A button appears on the taskbar for each program.

One window is always on top, which means it is the active window. The title bar of the active window is a different color than the title bars of all the other windows on your screen; in the default Windows desktop color scheme, the title bar of the active window is blue, while the other title bars are gray. Where the active window overlaps with another window, the active window obscures the other window.

Whatever you type on the keyboard is directed to the program in the active window. The programs in the other windows continue to run, but they don't receive input from your keyboard. To type information into a program, you switch the active window to a window displayed by that program.

16-Bit Versus 32-Bit Applications Older personal computers process data 16 bits at a time. These 16-bit computers are based on older CPUs (central processing units), like the Intel 8088 and 80286. Newer personal computers process data 32 bits at a time. These 32-bit computers are based on newer CPU chips, like the Intel 80386, 80486, Pentium, and Pentium Pro. DOS and Windows 3.1 run on both 16-bit and 32-bit computers. Windows 9x, Me, NT, 2000, and XP, as well as Linux and OS/2, all require 32-bit computers. Some programs are designed to run with DOS and Windows 3.1; these programs are called 16-bit applications. Other programs are designed to work with later versions of Windows and are called 32-bit applications. As a Windows XP user, you can run both 16-bit and 32-bit applications. (If you have Windows XP 64-Bit Edition running on a computer with an Intel Itanium processor, you can even run 64-bit programs!) When you have a choice, run the 32-bit version of a program, though; it takes better advantage of your 32-bit computer, and it usually runs faster and has more capabilities than the 16-bit version. If you have to run an older program, you can use compatibility mode to simulate an older version of Windows.

What Do the Parts of Windows Do?

Figure 2-1 shows a program (this example shows WordPad, a simple word processor that comes with Windows) running in a window. Although what's inside the window frame changes from program to program, most windows you see in Windows include the following components:

Figure 2-1: The parts of a window

• System Menu button Displays a menu of commands you can use to move and resize your window.
• Title bar Displays the title of the window and provides a way to move the window around within the screen.
• Minimize button Shrinks the window to an icon on the taskbar.
• Maximize or Restore button When you click the Maximize button, the window expands to cover the whole screen. Once a window has been maximized, the Maximize button disappears and is replaced by the Restore button. When you click the Restore button (with two overlapping rectangles), the window shrinks to its previous size and the Maximize button reappears.
• Close button Closes the window and exits the program.
• Menu bar Provides a row of menus you can use to choose commands.
• Toolbar Provides a row of buttons you can click to give commands.
• Status bar Displays information about the program. Some programs enable you to give commands by clicking parts of the status bar.
• Scroll bar Provides a way to "pan" your window up and down, or left and right to show information that doesn't fit in the window. Scroll bars may be horizontal (running along the bottom edge of a window) or vertical (running down the right edge of a window). All scroll bars have arrow buttons at each end and a sliding gray box somewhere in the scroll bar; some programs display scroll bars with additional buttons (for example, to scroll one page of a document at a time). The length or width of a scroll bar represents the entire length or width of the document you are viewing, and the sliding box represents the part of the document you can currently see. To change which part of the document you can see, click the arrow button at one end of the scroll bar, or click-and-drag the sliding gray box along the scroll bar.
• Window borders Provide a way to drag around the edges of the window to change the size and shape of the window.

What Is the System Menu?

You can also display the System menu by pressing ALT-SPACEBAR or by right-clicking the title bar of the window.

The commands on the System menu do the following:

• Restore Resizes the window to its previous size, the same as the Restore button.
• Move Enables you to move the window around on your screen by using the cursor (arrow) keys. This command does the same thing as dragging the window's title bar with the mouse. Press ENTER to finish moving the window.
• Size Enables you to change the size of the window by using the cursor keys. This command does the same thing as dragging the window borders with the mouse.
• Minimize Minimizes the window, shrinking it to a small icon, the same as the Minimize button.
• Maximize Maximizes the window to cover the whole screen, the same as the Maximize button.
• Close Closes the window, the same as the Close button.

Some applications also add their own commands to the System menu.