Mac OS 8 and 9 Developer Documentation: Operating System Services

PATH Mac OS 8 and 9 Developer Documentation > Operating System Services

The following technologies provide low-level operating system support for applications and device drivers. These services, ranging from memory management to process management are generally devoid of a user interface.

Event Manager
The Toolbox Event Manager provides routines that communicate information about actions performed by the user and give notice of changes in the processing status of your application. The Event Manager also provides routines that your application can use to communicate with other applications.

Gestalt Manager
The Gestalt Manager provides a simple, efficient way for your application to determine the user’s hardware and software configuration at runtime so that you can fully exploit the available features or inform the user if a necessary feature is missing.

Memory Management Utilities
The Memory Management Utilities provide specialized routines you can use to examine or control certain aspects of the memory environment. Many of these routines are 68K-specific, and most are unnecessary or unsupported in Carbon.

Memory Manager
The Memory Manager is the part of the operating system that controls the dynamic allocation of memory space.

Multiprocessing Services
Multiprocessing Services provide routines that allow your application to create separate threads of execution called tasks. Tasks are preemptively scheduled on the available processors in the system, even if there is only one processor.

Notification Manager
The Notification Manager provides routines that allow software running in the background (or otherwise unseen by the user) to communicate information to the user.

Process Manager
The Process Manager controls access to shared resources and manages the scheduling and execution of applications. It allows multiple applications to share CPU time and system resources.

Queue Utilities
The Queue Utilities provide routines that let you manipulate queue data structures maintained by the Mac OS. You can also use the Queue Utilities to create and manipulate your own queues.

Shutdown Manager
The Shutdown Manager gives applications and other software a chance to perform any necessary processing before the computer is turned off or restarted.

Start Manager
The Start Manager controls the system startup process and provides routines that let you specify the default startup device, default video device, and other settings. You should read about the Start Manager if you are developing a device driver or system extension that must be loaded during the startup process.

System Error Handler
The System Error Handler assumes control of the system when an error occurs and handles displaying any error messages to the user.

Thread Manager
The Thread Manager provides a programming interface to create cooperative execution threads in your application. These threads are cooperatively scheduled in a manner similar to the way the Mac OS 8 Process Manager schedules applications.

Time Manager
The Time Manager allows applications and other software to schedule routines for execution at a later time. It provides a hardware-independent method of performing time-related tasks.

Vertical Retrace Manager
The Vertical Retrace Manager schedules and executes tasks during vertical retrace interrupts. You can use the Vertical Retrace Manager to execute simple, repetitive tasks and avoid having to execute those tasks repeatedly in your application's main event loop.

Virtual Memory Manager
The Virtual Memory Manager is the part of the Mac OS that allows memory to be extended beyond the limits of the physical address space provided by the available RAM.