ID Number: Q78639
1.00 1.10 1.11 4.20
OS/2
Summary:
SYMPTOMS
This information applies to versions 1.x and 4.2 of SQL Server.
A trap 2 error may occur periodically on SQL Server, halting all
processing and causing the machine to be rebooted.
CAUSE
Trap 2, also known as a nonmaskable interrupt, is a hardware
problem.
There is parity logic that monitors each memory reference on the
memory subsystem of all PCs. If a parity error is encountered, the
NMI (nonmaskable interrupt) pin of the Intel processor is asserted.
This immediately causes control to be transferred to a short
routine that prints out register information, and then halts the
CPU.
There is an ISA bus signal called IOCHCK (I/O channel check) that
can be asserted by any adapter card. IOCHCK is intended for use by
adapter cards as a means of notifying the CPU that an
off-motherboard memory parity error has occurred. IOCHCK is gated
to NMI, and results in essentially the same outcome. The interrupt
service routine can query a register and determine whether the
parity error is from the motherboard or adapter card.
The IOCHCK signal is sometimes incorrectly used by certain video
cards to trigger a desired software routine. If the software
routine is not loaded correctly, the system will halt with a trap
2 error.
A variety of hardware configuration problems can also create a trap
2 condition, either by incorrectly asserting IOCHCK, or by fooling
the motherboard parity logic into thinking a true parity error
occurred. For example, if adapter cards containing RAM are
configured with conflicting memory footprints with respect to each
other or to the motherboard, a trap 2 parity error can result.
Running memory diagnostics for a period of time without failure
does not indicate a properly functioning system.
PC memory subsystem design virtually guarantees any OS/2 trap 2 is
a hardware problem. Resolution of this condition should center on
replacing the failing memory, or resolving a possible hardware
configuration problem.
STATUS
Trap 2 is an OS/2 fatal error caused by a hardware problem. It is
not a SQL Server, OS/2, or application software error.
Additional reference words: 1.00 1.10 1.11 4.20