Operating Systems & RTOS

Operating Systems & RTOS

Use this page to revise OS vocabulary as it applies to MCUs and SBCs.

Why an OS

An OS multiplexes CPU, memory, and I/O. On a laptop that is obvious. On an MCU you may have no OS (super-loop), a scheduler/RTOS, or Linux on a larger SoC.

Processes, threads, tasks

A process has its own address space (Linux). A thread shares it. An RTOS task is usually closer to a thread. Context switch costs time. Priority decides who runs.

RTOS objects

Mutex for mutual exclusion, queue for messages, semaphore for signalling. Priority inversion is when a low-priority task holds a lock a high-priority task needs. Watchdog resets a stuck system.

Starting Points

• Real-time systems
• RTOS application development
• FreeRTOS. RTOS fundamentals.

Key Points

• You can explain when bare metal vs. RTOS vs. Linux is the usual fit.
• You can contrast a Linux process with an RTOS task at a high level.
• You can explain mutex vs. queue in one sentence each.
• You can explain priority inversion in plain language.
• You can explain what a watchdog is for.