Applications are software packages that you use to do your work. For example, a word processor is an application with which you create and modify documents such as business letters and mailing lists. Applications work at the highest level of computer networking. You use applications as an interface through which you can access the resources of the computer as well as resources on the network to which your computer is connected. Commonly used application software includes word processing, accounting, spreadsheet, database, and e-mail programs. You may even use customized or one-of-a-kind applications built specifically for your company.
One important issue to consider when selecting application software is its degree of network and intranetwork integration. Not all applications are designed for network use. To effectively use network and intranet services, application software must be well suited to the computer network environment. The level of network integration built into any application determines how well you are able to collaborate with others, whether you can access network services, and how easy the application is to manage across the network.
Applications cannot function by themselves: they require resources provided by the computer hardware such as memory, storage devices such as hard disks, and peripheral devices (printers, fax machines, modems, etc.). For example, while using an application you might need to store documents on the hard disk in the computer on which the application is running. However, applications do not have the capacity to run hardware. An operating system, on the other hand, is software that controls the hardware, and therefore acts as an intermediary between applications and hardware. If you need to store or "save" a document on the hard drive, you would employ the application's conventions to give the save command (such as a certain keystroke); in turn, the application would pass the command to the operating system, which would direct the hardware to record the document on the hard drive. The diagram below illustrates the interaction between the application software, the operating system, and the computer hardware.
Figure 1: The function of applications and operating systems within a computer
Once you understand how applications function in this scenario, it is easy to see the importance of the operating system through which the application gains access to network resources and services. There are two types of operating systems necessary in computer networking: the desktop operating system and the network operating system. The next section discusses how the desktop operating system creates the environment necessary for application software to do its work.Return to Primer Index | Next Section