Stage 3 · Lesson 9 of 9
Processes and the operating system
The (OS) sits between your program and the hardware. When you run a program, the OS creates a process: a running instance of the program with its own memory, open files and at least one thread of execution. The OS shares time between hundreds of processes by switching between them very quickly.
Your code asks the OS for anything outside its own memory, such as reading a file, opening a network connection or printing. It does this through . Threads are separate paths of execution inside one process, and they share its memory.
That is powerful, and also a source of hard bugs. This is what makes task managers, kill, and "permission denied" errors make sense.
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Resources for this stage
Start with· follow one of these
- CourseFreeCS50: Introduction to Computer Science
Harvard University · Beginner
Weeks 0, 1, 2 and 4 teach C, arrays and memory; the difficulty is the point
- VideoFreeCrash Course Computer Science
CrashCourse · Beginner
Short free videos from logic gates to operating systems; episodes 1 to 20
Keep handy
Also worth your time
- What Happens WhenGo deeper
Everything from a key press to a rendered page; read it after this stage