[comp.sys.ibm.pc.hardware] Exception #13

Brian.Chan@samba.acs.unc.edu (Brian Chan) (03/21/91)

I have a Gateway 386 w/16Megs of RAM and I will  get an error exception
#13 once in awhile running apps. If I choose `c` to continue, 9/10 times the
machine will require hardare reset. Can someone kindly tell me what exp
#13 is?

Thx,

Brian Chan
Stuttgart, FRG


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jtw@cbnewsh.att.com (jui-tai.wang) (03/22/91)

In article <3026@beguine.UUCP>, Brian.Chan@samba.acs.unc.edu (Brian Chan) writes:
> I have a Gateway 386 w/16Megs of RAM and I will  get an error exception
> #13 once in awhile running apps. If I choose `c` to continue, 9/10 times the

Quote from "80386 System Software Writer's Guide" bu Intel, pg 3-11 (Section
about Interrupts and Exceptions):

"3.3.8 General Protection Fault, Number 13

The 80386 raises this fault when a task attempts an operation that is
inconsistent with a segment descriptor. Many such conditions exist, including
writing to a read-only segment, loading a null selector, and accessing a more
privileged segment....In priatice, however, a general protection fault in a
protected mode task indicates a serious program bug and the task should
usually be terminated. V86 tasks, on the other hand, can legitimately raise
this exception to signal the virtual machine monitor to simulate an
instruction...."

I guess you have to find out what program cause you this, can maybe check
with Gateway to see if this has anything to do with your BIOS/DOS also

Richard Wang
ATT-Bl
att!corona!jtw
standard disclaimer follow.

vcl@mimas.UUCP (Victor C. Limary) (03/22/91)

Brian.Chan@samba.acs.unc.edu (Brian Chan) writes:

> I have a Gateway 386 w/16Megs of RAM and I will  get an error exception
> #13 once in awhile running apps. If I choose `c` to continue, 9/10 times the
> machine will require hardare reset. Can someone kindly tell me what exp
> #13 is?
> 
> Thx,
> 
> Brian Chan
> Stuttgart, FRG

I get it sometimes too.  I would assume that you're using QEMM.  Am I 
correct?  I'm not sure what it means, but it's better than just having 
the computer lock up without you knowing!

       _______
      /       \
     |  O   O  |         Victor Limary
    <|    <    |>        mimas!vcl@bbx.basis.com
     |  _____  |
      \   U   /
       "-----"

ewadams@netcom.COM (Ernest Adams) (03/23/91)

If you *are* running QEMM, Exception 13 is occurring because some process
is trying to write to an area that QEMM believes belongs to someone else.
QEMM puts the processor in protected mode, which means that programs
which try to write outside their own space get caught.  The usual offenders
are games, which often hack areas in the BIOS for their own nasty reasons.

Ernest

dgil@pa.reuter.COM (Dave Gillett) (03/26/91)

In <3026@beguine.UUCP> Brian.Chan@samba.acs.unc.edu (Brian Chan) writes:

>I have a Gateway 386 w/16Megs of RAM and I will  get an error exception
>#13 once in awhile running apps. If I choose `c` to continue, 9/10 times the
>machine will require hardare reset. Can someone kindly tell me what exp
>#13 is?


     The only "Exception #13" message I've ever seen is from QEMM, and
clearly identifies itself as such.  Are we to infer that you are running
QEMM on the machine?

     Exception #13 is (very briefly) described in the QEMM manual; it means
that QEMM has detected the effect of an invalid address operation, usually due
to a corrupted or uninitialized pointer.  It's roughly equivalent to Windows'
"This app has violated system integrity" message; odds that the system can 
continue to run are extremely poor, and re-boot is the safest choice.
                                                Dave

mikel@teda.UUCP (Mikel Lechner) (03/28/91)

dgil@pa.reuter.COM (Dave Gillett) writes:

>In <3026@beguine.UUCP> Brian.Chan@samba.acs.unc.edu (Brian Chan) writes:

>>[. . .] Can someone kindly tell me what exp #13 is?

Quoted from Intel's 80386 "System Software Writer's Guide":

The 80386 raises this fault when a task attempts an operation that is
inconsistent with a segment descriptor.  Many such conditions exist,
including writing to a read-only segment, loading a null selector, and
accessing a more privileged segment. [. . .]  In practice, however,
a general protection fault is a protected mode task indicates a serious
program bug and the task should normally be terminated. [. . .]

>     the only "exception #13" message i've ever seen is from qemm, and
>clearly identifies itself as such.  are we to infer that you are running
>qemm on the machine?

qemm is not the only software that runs protected mode.  ergo's os28/386
dos extender will also print and exception #13 message when a program
running in protected mode gets an exception #13.

-- 
Mikel Lechner			UUCP:  teda!mikel
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