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SCSI Setup & Basic SCSI Troubleshooting in Windows

This article was previously published under Q133285
If this article does not describe the error message that you are receiving, view the following Microsoft Knowledge Base article to view more articles that describe error messages:
315854 Windows 98 and Windows Me Error Message Resource Center
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This article describes setup and troubleshooting tips that you can use forSCSI controllers in Windows.

Setting Up SCSI Adapters in Windows 95 and Windows 98

Before installing the Windows protected-mode drivers for your SCSIadapter, make sure the adapter is working in a real-mode configuration.Verify that the drivers for the adapter are loading in the Config.sysand/or Autoexec.bat files. Once the adapter is working correctly in realmode you can set up its protected-mode drivers. NOTE: This section does not apply to Windows Millennium Edition (Me).

To install a Windows protected-mode SCSI controller driver, run the AddNew Hardware Wizard from Control Panel. Windows currently supports SCSIand SCSI 2 adapter types. If Windows cannot detect your SCSI adapter,manually select your adapter from the list of SCSI controllers in the AddNew Hardware Wizard.

If your controller card is not listed, Windows does not currentlysupport it. Windows will not load protected-mode drivers for the adapterand you must use real-mode drivers. You may want to contact the cardmanufacturer to see if a protected-mode driver is available for Windows.

Plug and Play SCSI Specifications

  • The adapter must support at least the SCAM level 1 protocol for automatic SCSI ID assignment. SCAM (SCSI Configured Automatically) refers to a proposal for the SCSI-3 interface standard.
  • Automatic termination of the SCSI bus by the SCSI controller must occur.
SCSI controllers that do not meet these requirements may be compatiblewith Windows but are not supported with Plug and Play functionality.


One of the first steps in troubleshooting is to remove a conflictingdevice driver and reinstall it in Device Manager. An exclamation point ina yellow circle or an "X" in a red circle in Device Manager indicates apotential hardware conflict or a device that has been disabled. RestartWindows in Safe mode and remove any conflicting SCSI device drivers inDevice Manager. Restart Windows normally and start the Add New HardwareWizard by double-clicking the Add New Hardware icon in Control Panel.

If you are still experiencing problems, check the following items:
  • The SCSI bus must be configured properly for Windows to load protected-mode drivers. The configuration of a SCSI bus can be separated into the two following processes:

    1. Configuring the SCSI bus itself. This includes terminating both ends of the SCSI bus, setting the Logical Unit Number (LUN), and setting the device IDs. The LUN is used to designate which SCSI controller is being accessed in a system with more than one controller being used. The SCSI device ID is similar, but is the designation for multiple devices on one controller.

      Check to make sure that termination is correct. Incorrect termination is a common problem when setting up SCSI devices. Consult the SCSI controller manual or manufacturer for details on configuring your SCSI bus.
    2. Configuring the SCSI host adapter. This includes assigning its IRQ line, DMA channel, UMB range, and so on. Consult the SCSI controller manual or manufacturer for details.
  • Most ASPI-compliant cards have an option to enable or disable their boot ROM BIOS. Enabling the BIOS makes the SCSI drive bootable. However, SCSI drives are commonly used as a secondary disk subsystems (with the traditional IDE/ATA drive serving as the boot disk subsystem). Disable the BIOS if the computer does not boot from the SCSI drive.
  • For Windows 95 and Windows 98, if the SCSI card works in MS-DOS but is not fully functional in Windows using the protected-mode drivers, look at the parameters in the real-mode driver line in the Config.sys file and modify the switches or parameters on the Settings tab in Device Manager. The Windows drivers support only the switches and parameters supported by the real-mode drivers provided by the manufacturer.
  • For Windows 95 and Windows 98, Windows may have problems switching from real-mode drivers to protected-mode drivers with untested third-party real-mode drivers. Temporarily disable the real-mode drivers in the Config.sys and/or Autoexec.bat files by placing the word "rem" (without quotation marks) at the beginning of the driver lines. Restart Windows and try accessing the SCSI drive or check Device Manager for non-functioning devices.
  • Examine the Bootlog.txt file. Check the following items:

    • Are the SCSI drivers being initialized properly?
    • Can the SCSI drive be accessed at all?
    • Is a Windows protection error (WPE) received and is a SCSI VxD/MPD/PDR the last entry in the file?
HWSCSI 98 tshoot w95hwfaq real mode

Article ID: 133285 - Last Review: 01/19/2007 13:27:22 - Revision: 2.1

  • Microsoft Windows Millennium Edition
  • Microsoft Windows 98 Second Edition
  • Microsoft Windows 98 Standard Edition
  • Microsoft Windows 95
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