The layers.
WHAT THE LAYERS ARE
Hardware, at the bottom Firmware, initialising it The operating system, managing it Applications, using it through the operating system
WHAT THE OPERATING SYSTEM DOES
Manages processor time between programs Allocates memory Controls access to storage and devices Enforces permissions Provides services applications use
WHY APPLICATIONS DO NOT ACCESS HARDWARE DIRECTLY
So they cannot interfere with each other, and so they work across different hardware.
WHAT DRIVERS DO
Translate between the operating system and specific hardware.
WHY THEY CAUSE PROBLEMS
They run with high privilege, and a faulty one destabilises the whole system.
WHAT THAT EXPLAINS
Why many crashes trace to drivers rather than applications.
WHAT FIRMWARE DOES
Initialises hardware and starts the operating system.
WHY IT MATTERS IN SUPPORT
Settings there determine boot behaviour, and some problems can only be resolved at that level.
WHAT TO UNDERSTAND
Which layer a symptom belongs to, which directs the diagnosis.
