G:\MYDOCU~1\RTSIOC~1\OS-9\OS9_6X09\MANUALS\LEVEL2~1\TECHIN~1\HTML\CH2~1\OS-9 L-II Technical Reference Ch 2.htm

Chapter 2

The Kernel

The kernel is the core of OS-9. The kernel supervises the system

and manages system resources. Half of the kernel (called

OS9P1) resides in the boot module. The other half of the kernel

(called OS9P2) is loaded into RAM with the other OS-9 modules.

The kernel's main functions are:

System initialization after reset

Service request processing

Memory management

Multiprogramming management

Interrupt processing

I/0 functions are not included in the list because the kernel does

not directly process them. Instead, it passes I/0 system calls to

the 1/0 Manager for processing.

System Initialization

After a hardware reset, the kernel initializes the system. This

involves:

1. Locating modules loaded in memory from the OS-9 Boot file.
2. Determining the amount of available RAM.

3. Loading any required modules that were not loaded from the

OS-9 Boot file.

OS9P3 is a system module added to Version 1.2 of Level Two.

OS-9 calls the module during a cold start. This feature lets you