Apple II
File Type Notes
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                                                  Developer Technical Support


File Type:         $B3 (179)
Auxiliary Type:    All

Full Name:     ProDOS 16 or GS/OS Application
Short Name:    GS/OS Application

Written by:    Dave Lyons & Matt Deatherage                    September 1989

Files of this type and auxiliary type contain application programs for the 
Apple IIGS.
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Files of type $B3 contains GS/OS 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 in a documented environment.

The environment and constraints for application programs are documented in 
GS/OS Reference; all developers creating file of type $B3 should be familiar 
with this material.  OMF is documented in GS/OS Reference and the APW 
Reference Manual.

The auxiliary type for $B3 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)