SAS Companion for the OS/390 Environment

Other Considerations for Improving Performance

Leave AUTOSCROLL 0 in effect for the LOG and OUTPUT windows

The AUTOSCROLL command controls how information is scrolled as it is written to the LOG and OUTPUT windows. Specifying small scrolling increments is very expensive in terms of response time, network data traffic, and CPU time.

Under OS/390, AUTOSCROLL is preset to 0 for the LOG window. AUTOSCROLL 0 suppresses automatic scrolling and positions the LOG window at the bottom of the most recent output when a DATA step or procedure is completed. At that time, of course, you can scroll up to view the contents of the log.

To see the effect of this command, enter AUTOSCROLL 1 on the command line of the LOG window and then run PROC OPTIONS. Then enter AUTOSCROLL 0 and run PROC OPTIONS again. The CPU time ratio is more than 30 to 1.

Use the EM3179 device driver when appropriate

If you are running Attachmate or any other full-functioned 3270 emulator over a slow connection, specify the SAS system option FSDEVICE=EM3179 when you invoke SAS. Menus in applications such as SAS/ASSIST are then displayed as text menus instead of icon menus. The text menus require much less network data transfer and are considerably faster across slow lines.

Consider using the direct log-on procedure to invoke SAS

When you use the direct log-on procedure to invoke SAS instead of the TSO log-on procedure, SAS acts as your terminal monitor program. The direct log-on procedure has three potential advantages for your installation:

It eliminates the need for SAS users to know anything about TSO.
It saves a small amount of memory (approximately 50KB per user) in working-set size.
If you license TSO/E as a measured usage product, then you may be able to reduce your TSO charges significantly because CPU time for SAS applications will no longer be accumulated as TSO/E usage.

For a sample log-on procedure and other information about configuring it into the environment at your site, see the installation instructions for the SAS System in the OS/390 environment.

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