Files of this type contain Apple IIgs Classic Desk Accessories in OMF format.
Classic Desk Accessories are available by pressing Command-Ctrl-Esc, whether or not a desktop application is running.
Files of type $B9 in the System:Desk.Accs directory of the boot volume are automatically loaded with the Loader and installed into the system with InstallCDA at boot time. Bit 15 of the auxiliary type is the "inactive" bit -- if it's set, GS/OS does not load the CDA. All other bits in the auxiliary type are reserved and should be zero.
CDAs are stored on disk in Object Module Format, which is defined in Appendix F of GS/OS Reference. Once the Loader brings your CDA's code into memory, the format is as specified in the Desk Manager chapter of Apple IIgs Toolbox Reference, volume 1.
CDA authors should be sure to read the material listed under "Further Reference."
This and all of the other Apple II Technical Notes have been converted to HTML by Aaron Heiss as a public service to the Apple II community, with permission by Apple Computer, Inc. Any and all trademarks, registered and otherwise, are properties of their owners.