The main families.
WINDOWS
Dominant on business desktops.
Extensive application support, centralised management, familiar to most users.
MACOS
Common in design and creative work, and increasingly general use.
Unix-based underneath.
LINUX
Dominant on servers and in hosting.
Free, highly configurable, available in many distributions.
WHAT A DISTRIBUTION IS
A packaging of the Linux kernel with system software and tools, differing in defaults, package management and support.
MOBILE SYSTEMS
Android and iOS, with different application and management models.
WHAT DIFFERS BETWEEN THEM
File system layout and conventions Package and software installation Permission models Management tooling Command-line environments
WHAT IS COMMON
Processes, permissions, file systems, networking.
WHAT TO LEARN
Concepts first, then the specifics of whichever you support.
WHY
Concepts transfer. Specifics do not, and change anyway.
WHAT DETERMINES CHOICE IN AN ORGANISATION
Application requirements, management capability, cost and skills available.
