Hard Drives That Require VirtualHDIrq=off Switch in SYSTEM.INI (68725)


The information in this article applies to:

  • Microsoft Windows 3.0
  • Microsoft Windows 3.0a
This article was previously published under Q68725

SUMMARY

Microsoft Windows 3.0 may have problems operating in 386 enhanced mode with some nonstandard hard disks and hard disk controllers. It may be necessary to use the

VirtualHDIrq=

switch in the SYSTEM.INI file to enable Windows to run in 386 enhanced mode.

MORE INFORMATION

The VirtualHDIrq=<Boolean> switch allows Windows in 386 enhanced mode to terminate interrupts from the hard disk controller, bypassing the ROM routine that handles these interrupts. Some hard drives might require that this setting be disabled in order for interrupts to be processed correctly. If this setting is disabled, the ROM routine handles the interrupts.

To disable Windows from handling the hard disk termination interrupt routines, place the following line in the SYSTEM.INI file under the [386Enh] section:

VirtualHDIRQ=off

The following is a list of hard drives that are known to require the VirtualHDIrq=off switch in the SYSTEM.INI file: 
   Drive                              Size          Type
   -----                              ----          ----

   Seagate Wren Swift 94354                         ESDI
   Microscience HH-1090               80 MB         MFM
   Western Digital (WD) Caviar 280    80 MB         IDE
In addition, Ontrack's Disk Manager partitioning utility may need this switch.

REFERENCES

SYSINI3.TXT, Windows 3.00, directory where Windows is installed (generally the WINDOWS directory).
Modification Type:MinorLast Reviewed:7/7/2005
Keywords:KB68725
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