Windows XP Kernel Architecture Mike Karlsven James Farrer Jason Smith

Introduction Modeled on a microkernel architecture –Modified microkernel architecture Components execute in kernel mode rather than user mode Layered operating system

Executive HAL (Hardware Abstraction Layer) MicrokernelDevice Drivers Configuration Manager Cache ManagerObject Manager Virtual Memory Manager Security Reference Monitor Power Manager Plug and Play Manager I/O Manager Native API Interface Hardware Kernel Space Physical Hardware User Space Environment Subsystems User ProcessDLLUser Process

Hardware Abstraction Layer (HAL) Interacts directly with the hardware Handles device components on mainboard –Cache, system timers, etc Interacts with the microkernel HAL and Microkernel combine to make Windows XP portable allowing it to run in many different hardware environments

Windows Kernel Source Code #include char make_prog_look_big[ ]; main() { if (detect_cache()) disable_cache(); if (fast_cpu()) set_wait_states(lots); set_mouse(speed, very_slow); set_mouse(action, jumpy); set_mouse(reaction, sometimes); printf("Welcome to Windoze (we might get it right \ or just call it Chicargo)\n"); if (system_ok()) crash(to_dos_prompt); else system_memory = open("a:\swp0001.swp", O_CREATE); while(1) { sleep(5); get_user_input(); sleep(5); act_on_user_input(); sleep(5); if (rand() < 0.9) crash(complete_system); } return(unrecoverable_system); }

Microkernel Provides base services for the other components residing in kernel space Forms only small part of kernel space Provides basic system mechanisms –Thread scheduling Handles thread synchronization Dispatches interrupts Handles exceptions

Device Drivers Interacts with the microkernel and the HAL Interacts with Executive portion of the kernel space Inside kernel space

Executive Contains kernel-mode components responsible for administering the operating system subsystems –I/O Manager –Plug and Play Manager –Power Management –Security Reference Monitor –Virtual Memory Manager –Object Manager –Cache Manager –Configuration Manager Interacts with microkernel, device drivers, and native API interface

Native API Interface The interface directly to the executive’s services from the user level. Environment Subsystem The standard environment (e.g. win32). A layer of abstraction to translate the standard environment calls to system calls. Processes preferred method of interaction.

Example

Registry Database accessible to all process and Kernel-mode components Managed by the configuration manager (Executive Component) All drivers, components and applications communicate with the configuration manager to access the registry

Object Manager Executive Component that manages objects (physical and logical resources) Objects are access through object handles Kernel-mode components can access objects directly through pointers and through kernel handles (handles only accessible through kernel-mode)

Conclusion Designed to offer –Stability –Security –Scalability While still providing –Multimedia support –Networking –User friendly interface