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 | TIP: A computer without a program is useless, as is an orchestra without music to play. |
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Programs are what programs do. In fact, unless you use a program to do something, it is just another file taking up space on your computer disk. What any program does is to carry out instructions. Precisely what any particular program does depends upon the instructions that have been designed into it.
Programs accomplish what they do by doing such things as these:
acting as a messenger, translator, and negotiator between you and the operating system and the system processing unit
solving one particular problem—or a group of related problems—in ways that save you time and effort
taking information from somewhere
saving or storing information
sending information from one place to another
recalling (remember) information
carrying out instructions
manipulating information to produce new results
In general, programs (such as HP Easytime/iX) relieve you of the need to understand the workings of the operating system. They take information from you and do some of the needed processing. They make direct contact with the operating system to move your information where you want it, in the form you want it. In this sense, programs are your agents. Acting on your behalf, they draw up and execute "contracts" for the services provided by the operating system and the system processing unit.
The most sophisticated programs allow you to solve a problem, or to accomplish a task, in ways that are already familiar—or at least in ways that are less mysterious than the workings of the operating system.
A spreadsheet mimics the appearance and function of an accounting ledger. You may enter numbers (and words) in positions that define their relation to each other. You may define one number as being the sum (or difference, or product) of other numbers. If you later change one of the component numbers, the number you defined as being the sum (or difference, or product) changes with it automatically, almost instantly.
The most sophisticated programs do something else, as well. They protect you from—at the very least, they alert you to—impending problems. Using a spreadsheet in which you have entered numbers and words, it is surprisingly easy to tell the program to add a number and a word. In a moment of haste, you might tell the program to give " NDATA TIFF> Fix ESC characters.> you the result of 236.5+"January Sales". The system processing unit cannot perform this operation, and it would interpret the attempt as an error. An "alert" spreadsheet will <!— attempt the addition, —>recognize the problem and give you some message pointing out the problem and perhaps even suggest a resolution.
The rules for using any program are unique to that program. The documentation that comes with a program is your best source of information. Some programs actually suggest how to use them; some provide tutorials to help you learn how to use them; others provide helpful information that you can display on your terminal by pressing one or more keys.
Whenever possible, draw on the experience of others who have used a particular program.
