VESA Local Bus Device Conflicts in Windows NT

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

SUMMARY

When you use VESA local bus devices in a Windows NT computer with a fast processor, one of the following STOP error messages may appear:

   STOP 0x0000000A
   IRQL_NOT_LESS_OR_EQUAL

   STOP 0x0000007F
   UNEXPECTED_KERNEL_MODE_TRAP

   STOP 0x00000050
   PAGE_FAULT_IN_NONPAGED_AREA

RESOLUTION

To correct this problem, do one of the following:

• Disable the external cache on the computer. Some BIOS manufacturers include tuning parameters in the CMOS setup.

  -or-

• Add wait states to the L2 cache in the computer CMOS setup. This adjustment may compensate for slower devices.

MORE INFORMATION

A maximum of three VESA local (VL) bus connections can reside on a motherboard. Each slot contains up to one VL-bus device. For example, if a VL-bus device such as a video controller physically resides on the motherboard, only two VL-bus slots are then allowed in the system. The following table lists recommended maximum number of slots at various buffered or unbuffered speeds:

   CPU Speed                    Unbuffered        Buffered
   --------------------------------------------------------------

   Less or Equal to 33 MHz      2 slot/2 device   3 slot/3 device
   At 40 MHz                    1 slot/2 device   not recommended
   Greater or Equal to 50 MHz   0 slot/2 device   not recommended