What is processes?

A process is an instance of a computer program that is being executed. It includes the program’s code, its current activity (like which instructions are being run), the data it’s working with, and the resources it needs (such as memory, files, and CPU time). Think of it as a “living” version of a program that the operating system manages.

Let's break it down

  • Executable code: the actual instructions that tell the CPU what to do.
  • Memory space: a private area where the process stores its variables, stack, and heap.
  • Process ID (PID): a unique number the OS assigns so it can keep track of the process.
  • Resources: handles to files, network sockets, and other system objects the process uses.
  • Lifecycle stages: created → ready (waiting for CPU) → running (executing) → blocked (waiting for I/O) → terminated (finished).

Why does it matter?

Processes let a computer run many programs at once without them interfering with each other. They provide isolation, so if one program crashes, it doesn’t take the whole system down. They also enable multitasking, better use of CPU time, and help enforce security boundaries between applications.

Where is it used?

Every modern operating system-Windows, macOS, Linux, Android, iOS-uses processes. They appear in desktop apps, web browsers, server software, mobile apps, video games, and even tiny embedded devices that need to run more than one task at a time.

Good things about it

  • Isolation: each process has its own memory, protecting others from accidental or malicious changes.
  • Stability: a crash in one process usually doesn’t affect the rest of the system.
  • Security: permissions can be set per process, limiting what it can access.
  • Concurrency: multiple processes can run simultaneously, improving performance on multi‑core CPUs.
  • Resource control: the OS can limit CPU, memory, and I/O usage per process.

Not-so-good things

  • Overhead: each process consumes memory and system resources, which can add up quickly.
  • Context switching cost: switching the CPU between processes takes time, reducing efficiency.
  • Complexity: managing many processes (communication, synchronization) can be harder for developers.
  • Limited scalability: creating too many processes can exhaust system limits, leading to performance degradation.