Re: Defender of the World

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

Devin Reade <glyn@cs.ualberta.ca> wrote:

> Hey folks,
> 
> Aaron and I are trying to figure out why a particular program will 
> sometimes fail when launched from ProSEL-16 or GNO, but will work fine
> from the Finder or ORCA/Shell.
> 
> I seem to recall that DOTW has a similar problem (at least on the 
> surface).  With DOTW, one will get a "Fatal Error $0046" on launch.
> However this other program (call it "SB") gets bad data, as if
> I/O is not happening right.

Error $0046 is "file not found".

One possibility is that the program is assuming one of the GS/OS
numbered prefixes has been set correctly, but GNO and ProSel-16 are not
setting it.

The most likely candidate is prefix 8, which is the GS/OS default
prefix, used when a partial pathname is entered.

GNO, in particular, uses the old ProDOS-16 prefix numbers, which go from
0 to 7.  It doesn't implement prefix 8 correctly.  ORCA/Shell does
implement it correctly, and I'm pretty sure Finder does.

If this is the problem, then strictly it is a bug in the application you
are launching, because no assumptions should be made about the setting
of prefix 8.  Finder probably sets it to the directory of the
application you are launching (I haven't verified this).  ORCA/Shell
leaves it whereever the current directory is set (usually done by the
shell startup file, or by the user).  GNO doesn't set it at all, so it
will contain whatever it was last set to.

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