Full Screen MS-DOS Application Runs Slowly

ID: q103406

The information in this article applies to:

Microsoft Windows NT operating system version 3.1
Microsoft Windows NT Advanced Server version 3.1

SYMPTOMS

At times, your graphical, MS-DOS-based application runs very slowly in full-screen mode. You may notice this behavior is triggered by switching the application between an icon and full screen state. Also, if you press a key, the application speeds up for a short time.

CAUSE

The Windows NT virtual MS-DOS machine (VDM) enabled idle time detection while the application was in full-screen mode. Because Windows NT does not trap video activity while an MS-DOS - based application is running in full-screen mode, it assumes the application is idle and reduces its execution priority. The reason the application speeds up when you press a key is that Windows NT detects keystrokes at all times; when the activity is noted, the status of the application is changed from idle to active.

RESOLUTION

If you experience this behavior, use PIF Editor to create a program information file (PIF) for your application. In the Advanced Options dialog box, disable Detect Idle Time under Multitasking Options.

Additional query words: prodnt

Keywords          : kb3rdparty kbinterop
Version           : 3.1
Platform          : WINDOWS

Last Reviewed: August 14, 1998