4.2 Using Software Systems

Reading Sequence:

• Parsons/Oja, Chapter 3-Sections B and C. Remark: Application software is a broad term applied to any software that is oriented toward helping a user to solve a problem. Learn about the major categories of application software that are available for computer systems. 

• 4.2.1. Lab: DOS Commands. Remark: DOS commands are an example of a command-line interface. Command-line interfaces are cryptic but powerful; computer experts often prefer them more than the GUI "point and click" interface preferred by novice users. This section of the course provides some additional information and practice related to the DOS command-line interface. 

• 4.2.2 Lab: Macros. Remark: "Macros" are predefined sequences of user commands and inputs that can be used repeatedly. They provide a faster way for accomplishing some repetitive tasks, and they can reduce the chance of errors due to typos or mouse-related mistakes.

• 4.2.3 Lab: Embedding Application Objects. Remark: Importing data objects such as a graphic or spreadsheet from one application into another is an increasingly common operation. This facilitates the creation of complex documents that can easily be updated using whichever application created the imported object.

Assessments:

• Multiple-Choice Quiz 13

Learning Exercise:

Perform the "DOS User Interface" lab on the CD that accompanies Parsons/Oja to practice using the DOS command-line interface. Do some additional exploring by trying the following:

Note: The help command is not available on all versions of DOS. If it is not available, you can view the help information for any command by including a slash-question mark switch ( /? ) on the command line after the command—like so, dir /?—and pressing ENTER.

• Type the help command on the DOS command line to see a list of all DOS commands. Then type help rmdir to see the Help entry for a particular command.

• The command color e9 changes the background and foreground text colors of the command window. Its argument is a hexadecimal number. Try it. Then try color 5b. For a list of colors, type help color. How can you set the color back to white-on-black?

• Some commands, such as dir, have Help entries that do not fit on a single screen. Type help dir | more to view the Help entry one screen at a time.

• The vertical bar ( | ) is pronounced "pipe." It is used to direct the output of one command (such as help) to the input of another (more, for example). The more command displays output one screen at a time; you must press the SPACEBAR to proceed to the next screen. However, with DOS systems, once you proceed to the next screen, there is no way to return to a preceding screen. (Modern applications with a GUI interface use a text window with a scroll bar to solve this problem.)

• If you are in the middle of a listing and you want to stop it, you can type CTRL+C. Example: type help; you will see the first screen of the Help entry. Then hold down the CTRL key and press the C key. Doing so will halt the display of the Help entry and will return you to the DOS command prompt.

• The assoc command (available in versions of Windows since Windows NT/2000 only) displays associations between file extensions and applications. Type assoc .doc and then assoc .txt. Be sure to include the period at the beginning of the extension.

• The set command is used to set environment variables, which provide additional parameters to programs. Typeset to see a list of the current variables and their values.

• Type exit to close the DOS interface window.