DOCUMENT:Q103406  04-NOV-1993  [W_NT]
TITLE   :Full Screen MS-DOS Application Runs Slowly
PRODUCT :Windows NT
PROD/VER:3.10
OPER/SYS:WINDOWS
KEYWORDS:BUGLIST

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The information in this article applies to:
 
 - Microsoft Windows NT operating system, version 3.1
 - Microsoft Windows NT Advanced Server, version 3.1
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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 reference words: 3.10
KBCategory:
KBSubCategory: 16AP

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Copyright Microsoft Corporation 1993.