Microsoft KB Archive/75488

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Floppy Disk Drive Problems in 386 Enhanced Mode

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Q75488

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The information in this article applies to:


 * Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11

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SYMPTOMS
If you are experiencing errors reading, writing, or formatting floppy disk drives while running Windows in 386 enhanced mode, follow the steps listed below to troubleshoot and resolve the problem.

WORKAROUND
 Exit Windows.  To determine whether your system is reading the floppy disk directory, insert a disk in drive A, and type the following at the MS-DOS command prompt: "dir a:" NOTE: If you remove the disk from drive A and type dir a: and the directory lists again, it is an indication of an improper CMOS version or incorrect hardware setup (for example, a 3.5-inch drive on a jumper for an XT computer).   To determine whether your system writes to the floppy disk drive, type the following at the MS-DOS command prompt "copy a:" where is any valid file on your hard disk.

If the commands in steps 2 and 3 do not work, the problem is at the MS-DOS level.   Restart your computer using the minimum information in your AUTOEXEC.BAT file and CONFIG.SYS file that your computer needs to start up. For more information about how to do this, query on the following words in the Microsoft Knowledge Base: "troubleshooting and autoexec.bat and config.sys and files" NOTE: Anti-Virus software commonly causes this problem.   Does the floppy disk drive read problem go away when you run Windows in standard mode or real mode? To test this, start Windows by typing the following at the MS-DOS command prompt: "win /s" If everything works correctly in Windows, you know that the problem is related only to running Windows in 386 enhanced mode.

If the problem is specifically related to 386 enhanced mode, you may be loading SYMEVNT.386 from Norton Utilities 8.0. For more information about SYMEVNT.386, query in the Microsoft Knowledge Base on the following words: "symevnt.386 and norton" If the problem is specifically related to 386 enhanced mode but you are not loading SYMEVNT.386, using the switches below may lessen the problem. Add these switches to the SYSTEM.INI file in the [386Enh] section in the order shown. If you find one of the switches works, you can try removing previous switches that had no effect. Note that the switches listed in item (b) should be added or removed as a pair. (See the MORE INFORMATION section of this article for an explanation of these switches.)

 IRQ9GLOBAL=YES HIGHFLOPPYREADS=NO

EMMEXCLUDE=E000-EFFF VirtualHDIrq=OFF</li></ol> </li> Insert a semicolon before the Load= and Run= lines in the WIN.INI file to ensure that nothing else is being loaded that could cause a problem.</li> Check to see if you can successfully issue commands in Windows at the MS-DOS command prompt. If commands work at the MS-DOS level, it indicates a BIOS or hard disk drive/floppy controller BIOS problem.</li> Is the floppy disk drive icon displayed in File Manager? If not, check your BIOS version and contact your hardware manufacturer for an update.</li> Disable any BIOS and video shadowing. Each computer may have a different way of disabling its shadowing. You will need to check your system documentation and follow the instructions provided there to perform this task.</li> Check for third-party or external floppy disk drivers.</li> Check the type and version of MS-DOS. MS-DOS versions earlier than 3.3 do not support 1.44-MB drives.</li> Check for hardware devices that may be using the same IRQ as the floppy disk drive controller. (By default, the floppy disk drive controller uses IRQ 6.)</li> Check to see if an IDE ATIO card is in use. This is an integrated card that contains a game port, serial port, parallel port, IDE, and floppy disk drive controller. Remove this card and insert a card that has only the IDE floppy disk drive controller on it.</li></ol>

MORE INFORMATION
The following paragraphs explain the switches used in step 5 above.

IRQ9Global=
Default: No

Purpose: If enabled, this switch converts IRQ9 masks to global. Enable this setting if your system stops responding (hangs) when accessing a floppy disk drive, or make sure your system accesses the floppy disk drive before you start Windows.

HighFloppyReads=
Default: Yes

Purpose: Normally, Windows turns a DMA verify to the area E000:0000- EFFF:FFFF into a read. In rare cases, this might cause the system to fail because some software might, as a result, write over the system's shadow RAM if you have it in this area. If this happens, disable this setting and set EMMExclude to E000-EFFF.

EMMExclude=<paragraph-range>
Default: None

Purpose: Specifies a range of memory that Windows will not scan to find unused address space. This has the side effect of turning off the RAM and ROM search code for the range. The range (two paragraph values separated by a hyphen) must be between A000 and EFFF. This scanning can interfere with some adapters that use the same memory area. The starting value is rounded down and the ending value is rounded up to a multiple of 16K. For example, you could set EMMExclude=C800-CFFF to prevent Windows from scanning the addresses C800:0000 through CFFF:000F. You can specify more than one range by including more than one EMMExclude line.

VirtualHDIrq=
Default: On

Purpose: If enabled, Windows in 386 enhanced mode can terminate interrupts from the hard disk controller, bypassing the ROM routine that handles these interrupts. Some hard disk drives may require this setting to be disabled for interrupts to be processed correctly. If this setting is disabled, the ROM routine handles the interrupts, which slows down system performance.

Additional query words: tshoot 3.00 3.00a 3.10 3.11 central point norton format

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Issue type :

Technology : kbWin3xSearch kbWin300 kbWin300a kbWin310 kbWin311