Apple IIgs #53
Desk Accessories and Tools

Revised by Dave "Out of Phase" Lyons (May 1992)
Written by Matt Deatherage, Jim Mensch, & Dave Lyons (March 1989)

This Technical Note discusses compatibility issues that can arise between desk accessories and applications. Where possible, it presents solutions.

Changes since March 1991: Updated information about QuickDraw Auxiliary and StartUpTools for System 6.0.

This Note presents guidelines to help applications and desk accessories work together smoothly.

Tool Sets

The greatest conflict between applications and desk accessories, especially NDAs, is the use of system tool sets. The Apple IIgs Toolbox Reference, Volume 1, defines the minimum collection of tools sets available to an NDA. The Desk Manager requires that an application start the following tool sets before calling DeskStartUp:

NDAs may assume that these tools are all present and running, so they do not need to check for their presence. NDAs can also use the following tool sets without special consideration for starting them up: Desk Manager, Scheduler, Apple Desktop Bus, and Integer Math.

In addition to the tool sets applications must start to support NDAs, Apple recommends that applications start the following tools:

These two additional tools are so widely used by desk accessories that they should be present. NDAs may not assume their presence, but it is reasonable to write an NDA that checks for them, with the assumption that they usually turn out to be available.

NDA Guidelines

Which Tool Sets Can an NDA Use?


TLStartUp AND TLShutDown

User Tool Sets Belong to the Application

Bank Zero Memory and Error $0201

QuickDraw Auxiliary

Sound Tools

Application Guidelines

For best compatibility with NDAs, applications should follow the following guidelines.

CDA Guidelines

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.