On 31 Mar 98 at 19:26, JMB wrote:

> The special test equipment software uses a DAC circuit card (Digital to
> Analog) which is added to an ISA slot in the computer.  It requires
> IRQ's 10 and 11 for use.
>
> The problem:  After the test equipment software was loaded, whenever an
> attempt was made to run it, Windows 95 (OSR2) came back with a blue
> screen with a fatal exception message on it.
>
> "A fatal exception OE has occurred at 0028:C003028C in VXD  VPICD ()L) +
> 00001AC8.... the application will be terminated ....."
>
> I tried to reserve a video memory area (is this a throwback to win 3.1x
> features??) in the SYSTEM.INI file under 386ENH by adding EMMEXCLUDE=
> A000-CFFF.  This did not seem to help at all.

  ISA D/A or A/D cards often included a buffer area to be mapped into
the top half of conventional memory; C800 is a pretty typical start
address.  Since the 386, it has been possible for CPUs to map system
memory into this region, and to work with such a card, that must be
prevented.
  In the project I currently work on, we are using an ISA telephony
card that requires that such a buffer be set aside.  Checking with
our motherboard manufacturer, we learned that this is a standard
feature of AMI (and probably also Award) BIOS frameworks, but that
they had chosen not to include it in their product fearing that it
would confuse most users.  They were able to supply us with a flash
BIOS upgrade to restore this function to the CMOS setup.

David G