WinNT 4.0 SP2 Atapi Claims IRQ for Unused IDE Channel (164391)


The information in this article applies to:

  • Microsoft Windows NT Workstation 4.0
  • Microsoft Windows NT Server 4.0
This article was previously published under Q164391

SYMPTOMS

After you install Windows NT 4.0 Service Pack 2, you find that you no longer have available a previously unused IRQ normally reserved for the secondary IDE controller, which is usually IRQ 15.

Another side effect may include IRQ conflicts between Atapi and another previously working adapter that was using the same IRQ prior to loading Service Pack 2.

Use Event Viewer and Microsoft Diagnostics to verify which devices are conflicting and which IRQ each adapter is claiming.

CAUSE

The device driver Atapi.sys erroneously claims the IRQ for the empty IDE secondary controller.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Modification Type:MajorLast Reviewed:8/10/2001
Keywords:kbbug kbsetup KB164391
©2002 Microsoft Corporation. All rights reserved.