What Is the SAS System?

Ways to Run SAS Programs

There are several ways to run SAS programs. They differ in the speed with which they run, the amount of computer resources that are required, and the amount of interaction that you have with the program (that is, the kinds of changes you can make while the program is running).

The examples in this documentation produce the same results, regardless of the way you run the programs. However, in a few cases, the way that you run a program determines the appearance of output. The following sections briefly introduce different ways to run SAS programs.

SAS Windowing Environment

The SAS windowing environment enables you to interact with SAS directly through a series of windows. You can use these windows to perform common tasks, such as locating and organizing files, entering and editing programs, reviewing log information, viewing procedure output, setting options, and more. If needed, you can issue operating system commands from within this environment. Or, you can suspend the current SAS windowing environment session, enter operating system commands, and then resume the SAS windowing environment session at a later time.

Using the SAS windowing environment is a quick and convenient way to program in SAS. It is especially useful for learning SAS and developing programs on small test files. Although it uses more computer resources than other techniques, using the SAS windowing environment can save a lot of program development time.

For more information about the SAS windowing environment, see Using the SAS Windowing Environment.

SAS/ASSIST Software

One important feature of SAS is the availability of SAS/ASSIST software. SAS/ASSIST provides a point-and-click interface that enables you to select the tasks that you want to perform. SAS then submits the SAS statements to accomplish those tasks. You do not need to know how to program in the SAS language in order to use SAS/ASSIST.

SAS/ASSIST works by submitting SAS statements just like the ones shown earlier in this section. In that way, it provides a number of features, but it does not represent the total functionality of SAS software. If you want to perform tasks other than those that are available in SAS/ASSIST, you need to learn to program in SAS as described in this documentation.

Noninteractive Mode

In noninteractive mode, you prepare a file that contains SAS statements and any system statements that are required by your operating environment, and submit the program. The program runs immediately and occupies your current workstation session. You cannot continue to work in that session while the program is running,(footnote 1) and you usually cannot interact with the program.(footnote 2) The log and procedure output go to prespecified destinations, and you usually do not see them until the program ends. To modify the program or correct errors, you must edit and resubmit the program.

Noninteractive execution may be faster than batch execution because the computer system runs the program immediately rather than waiting to schedule your program among other programs.

Batch Mode

To run a program in batch mode, you prepare a file that contains SAS statements and any system statements that are required by your operating environment, and then you submit the program.

You can then work on another task at your workstation. While you are working, the operating environment schedules your job for execution (along with jobs submitted by other people) and runs it. When execution is complete, you can look at the log and the procedure output.

The central feature of batch execution is that it is completely separate from other activities at your workstation. You do not see the program while it is running, and you cannot correct errors at the time they occur. The log and procedure output go to prespecified destinations; you can look at them only after the program has finished running. To modify the SAS program, you edit the program with the editor that is supported by your operating environment and submit a new batch job.

When sites charge for computer resources, batch processing is a relatively inexpensive way to execute programs. It is particularly useful for large programs or when you need to use your workstation for other tasks while the program is executing. However, for learning SAS or developing and testing new programs, using batch mode might not be efficient.

Interactive Line Mode

In an interactive line-mode session, you enter one line of a SAS program at a time, and SAS executes each DATA or PROC step automatically as soon as it recognizes the end of the step. You usually see procedure output immediately on your display monitor. Depending on your site's computer system and on your workstation, you may be able to scroll backward and forward to see different parts of your log and procedure output, or you may lose them when they scroll off the top of your screen. There are limited facilities for modifying programs and correcting errors.

Interactive line-mode sessions use fewer computer resources than a windowing environment. If you use line mode, you should familiarize yourself with the %INCLUDE, %LIST, and RUN statements in SAS Language Reference: Dictionary.

FOOTNOTE 1: In a workstation environment, you can switch to another window and continue working.

FOOTNOTE 2: Limited ways of interaction are available. You can, for example, use the asterisk (*) option in a %INCLUDE statement in your program.

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