Operating-Systems

COW lets the OS clone a process in microseconds by postponing actual copying, a technique that underpins containers, virtualization, and high‑performance servers.

Copy‑on‑write lets the kernel clone a process without copying its memory pages, deferring duplication until a write occurs, which dramatically speeds up fork.

Introduction The Journaled File System (JFS), originally developed by IBM, is a robust, high‑performance file system that has been part of the Linux ecosystem for more than two decades. While many modern Linux distributions ship with ext4 or XFS by default, JFS still holds a unique niche thanks to its low CPU overhead, excellent scalability, and reliable journaling capabilities. In this article we will explore JFS from the ground up: ...

Table of Contents Introduction What Is an IPC Unit? Fundamental IPC Mechanisms 3.1 Pipes and FIFOs 3.2 Message Queues 3.3 Shared Memory 3.4 Sockets 3.5 Signals and Semaphores Designing an IPC Unit in Software 4.1 Abstraction Layers 4.2 API Design Considerations 4.3 Error Handling & Robustness Hardware‑Accelerated IPC Units 5.1 Why Off‑load IPC to Silicon? 5.2 Typical Architecture of an IPC IP Block 5.3 Case Study: ARM CoreLink CCI‑400 & CCI‑500 Performance & Scalability 6.1 Latency vs. Throughput Trade‑offs 6.2 Benchmarking Methodologies 6.3 Optimization Techniques Security and Isolation 7.1 Namespace & Capability Models 7.2 Mitigating Common IPC Attacks Practical Examples 8.1 POSIX Shared Memory in C 8.2 ZeroMQ Pub/Sub Pattern in Python 8.3 Boost.Interprocess Message Queue in C++ Testing & Debugging IPC Units Future Directions Conclusion Resources Introduction Inter‑process communication (IPC) is the lifeblood of modern computing systems. Whether you’re building a microkernel, a high‑frequency trading platform, or an embedded sensor hub, the ability for distinct execution contexts to exchange data efficiently, safely, and predictably determines both performance and reliability. ...

Introduction The term exo‑kernel (sometimes written exo‑kernel or exokernel) refers to a radical approach to operating‑system (OS) design that pushes traditional kernel responsibilities out to user space. Unlike monolithic kernels, which bundle device drivers, file‑system logic, networking stacks, and many other services into a single privileged component, an exo‑kernel provides only the minimal abstractions required for secure resource multiplexing. All higher‑level policies—memory management strategies, file‑system semantics, scheduling algorithms, and even networking protocols—are implemented as user‑level libraries. ...