Apple II File Type Notes _____________________________________________________________________________ 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 Revised by: Dave Lyons March 1991 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. Changes since September 1989: Added a note about the state of the Super Hi-Res screen. _____________________________________________________________________________ Files of type $B5 contain 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 in 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) Note: If a Shell 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 make the QuickDraw II call GrafOff before the user can read error messages displayed on the text screen (it's OK to call GrafOff even if QuickDraw II is not active).