Event ID 28 from 8042prt on IBM PS/2 and Some PC Servers

• Microsoft Windows NT Workstation versions 3.5 and 3.51
• Microsoft Windows NT Server versions 3.5 and 3.51

SYMPTOMS

Windows NT logs the following error in the System Log (as seen in the Event Viewer) following a reboot:

   Source:      8042prt
   Type:        Information
   Category:    None
   Description: Could not successfully write the Controller Command Byte
                for the i8042.

CAUSE

The Windows NT initialization routine reads the Controller Command Byte (CCB) from the i8042prt, changes some CCB bits, writes it back, then verifies it. If the verification does not pass, the error is posted in the System Log. The keyboard driver also logs this error when it encounters glitches in operation.

This is by design and a valuable tool to determine problems when the keyboard actually stops working.

RESOLUTION

This is an informational message only and not an indication of a problem with the keyboard port.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.5 and 3.51 We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.