Apple II File Type Notes _____________________________________________________________________________ Developer Technical Support File Type: $B3 (179) Auxiliary Type: All Full Name: ProDOS 16 or GS/OS Application Short Name: GS/OS Application Revised by: Dave Lyons May 1992 Written by: Dave Lyons & Matt Deatherage September 1989 Files of this type and auxiliary type contain application programs for the Apple IIgs. CHANGES SINCE DECEMBER 1991: Broadened the definition auxiliary type bit 1 to mean the application can handle getting control with the Super Hi-Res screen on. _____________________________________________________________________________ Files of type $B3 contain 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 = application can handle the Super Hi-Res screen already being on when it first gets control, so the system can provide a smooth visual transition into the application 0 = application is not prepared for the Super Hi-Res screen to be on 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) NOTE: If an application has the Desktop Application bit set, it should be prepared to get control with either the text or the Super Hi-Res screen visible. For example, if some error prevents the application from using the desktop tools, it may be necessary to call GrafOff before the user can read error messages displayed on the text screen (although GrafOff is a QuickDraw II call, it's OK to call GrafOff even if QuickDraw II is not active). If an application does not have the Desktop Application bit set (or does not even have a $DBxx auxiliary type), the system software reserves the right to force the text screen to be visible if QuickDraw II is not started. Do not assume that a Quit call from one application to another (with QuickDraw II not started) will leave the Super Hi-Res screen visible.