Re: system error $0027

[dempson@actrix.gen.nz (David Empson)]

Rubywand <rubywand@swbell.net> wrote:

> David Empson writes ...
> > 
> > Michael Wicklund <tbogard1@MYhome.com> wrote:
> > 
> > > Supertimer:
> > > "Can someone tell me what system error $0027 means?  Thanks."
> > >
> > > System Failure- File map destroyed
> > 
> > Rubbish.
> 
>      Alas, that is the description supplied in the Apple IIgs Toolbox
> Reference Vol 2.

Ah, _that_ list.  I strongly suggest that any information derived from
the "system failure codes" list in table B-1 in Toolbox Ref volume 2 be
expunged from the FAQ.

These numbers are almost completely meaningless.  Some of them don't
even make sense on a IIgs, and may have been copied from Macintosh
documentation.

For example, all the errors referring to "Can't load a package" make no
sense - the IIgs doesn't have any such thing as a package (but early
Macintosh system software does, e.g. the Standard File toolset on the
Mac is actually a package loaded from the System file, not in the ROM).

Here is another big clue: error $30 is allegedly "Please insert disk
(File Manager alert)".  There is no such thing as the "File Manager" on
the IIgs, but there is on the Mac.

How about this for proof: Inside Macintosh, Volume III, page 176
(summary of the System Error Handler, in a table entitled "User
Alerts"):

Errors 1-3 and 5-14 have different meanings from the IIgs list, but the
following are identical:

4  Division by 0

Oh, this gets even better.  :-)

Error 15 in _decimal_ is "Segment loader error".
Errors 16 through 24 (decimal) are "Can't load a package".
Error 25 (decimal) is "Can't allocate requested memory block".
Error 26 (decimal) is "Segment loader error".
Error 27 (decimal) is "File map destroyed".
Error 28 (decmial) is "Stack overflow".
Error 30 (decimal) is "Please insert disk".
Error 100 (decimal) is "Can't mount startup volume".

These correspond exactly to the values listed in the IIgs toolbox
reference, except the IIgs values have been written as if they were hex
values.

Summary: most of the values in this table are copied verbatim
(incorrectly) from Macintosh documentation, and I strongly suspect none
of them have the slightest relevance to the IIgs.


The first few errors in the table (ProDOS-16 codes) may have some
meaning, but in any case they would only apply to a screen which shows a
"System failure" message, _not_ to error codes returned from OS calls.

There is a similar mechanism in ProDOS-8, e.g. used to report a system
failure due to an unclaimed interrupt.


Now, having said all that, the remaining sections of table B-1 are
reasonably OK.  There are bound to be a few errors in there, but none as
blatant as the so-called "system failure codes" list.


-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand