Apple II
File Type Notes
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                                                  Developer Technical Support


File Type:         $B5 (181)
Auxiliary Type:    All

Full Name:     ProDOS 16 or GS/OS Shell application file
Short Name:    GS/OS Shell application

Written by:    Dave Lyons & Matt Deatherage                    September 1989

Files of this type and auxiliary type contain application programs intended 
for use within a shell environment for the Apple IIGS.
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Files of type $B5 contains GS/OS shell application programs.  These files 
contain program code in Object Module Format (OMF) that is loaded by the 
System Loader or ExpressLoad at an address and is then executed under the 
control of a command shell (such as APW, for example).

The shell may provide extra services to a shell application that are not 
available to normal GS/OS applications (files of type $B3).  A shell 
application can identify which shell it is running under by examining the 
shell identifier.

Information about the shell identifier and other shell application environment 
issues may be found in GS/OS Reference and APW Reference, where the shell 
application environment is completely documented.  OMF is documented those 
manuals as well.  All developers creating files of type $B5 should be familiar 
with this material.

The auxiliary type for $B5 files is now defined to indicate properties of the 
program contained within the file.  Other parts of the system may use this 
information to properly control the environment for the program:

            bits 31-16       reserved--must be 0
            bits 15-8        signature byte.  $DB means bits 7-0 are valid
            bits 7-3         reserved--must be 0
            bit 2            Message Aware:
                             1 = uses Message Center message #1 
                             0 = ignores Message Center message #1
            bit 1            Desktop Application:
                             1 = uses desktop tools such as (at least) 
                                 QuickDraw II, Event Manager, Window 
                                 Manager, Control Manager, and Menu Manager
                             0 = doesn't use desktop tools
            bit 0            GS/OS Aware:
                             1 = uses long prefixes (for example, prefix 9 
                                 instead of prefix 1)
                             0 = uses short prefixes (less than 63 
                                 characters)