DOCUMENT:Q78435 17-DEC-2000 [msdos] TITLE :What Is EGA.SYS and What Is Its Function? PRODUCT :Microsoft Disk Operating System PROD/VER:MS-DOS:5.x OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft MS-DOS operating system versions 5.0, 5.0a ------------------------------------------------------------------------------- SUMMARY ======= This article briefly describes the EGA.SYS file, why it is needed, and when it will be automatically installed by the MS-DOS 5.0 Setup program. MORE INFORMATION ================ EGA.SYS is a device driver that allows different programs to be aware of the current state of the registers on an EGA video card. It is necessary because many registers on an EGA card can be written to by an application, but there is no way to read the registers to determine the current settings. This is a problem for programs such as MS-DOS Shell that must save and restore the computer screen. The solution to this problem is to require programs to record the current state of the EGA video registers in the EGA.SYS file. A program that changes the state of the video display can determine current settings by checking EGA.SYS. If EGA.SYS is not installed on a system that has an EGA video card, the screen may be unreadable after the user switches between two different graphics-oriented programs from within Shell. The MS-DOS 5.0 Setup program installs the EGA.SYS driver in the CONFIG.SYS file on any computer that it detects as having an EGA video card. Additional query words: 5.00 dosshell kbfest newfest ====================================================================== Keywords : Technology : kbMSDOSSearch kbMSDOS500 kbMSDOS500a Version : MS-DOS:5.x ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2000.