Program and process

Why this matters

A terminal can ask the operating system to start a program. Security tools inspect processes. Both ideas are confusing if “program” and “process” are treated as synonyms.

Stored instructions versus running work

A program can exist as files on storage. It is passive until something starts it. A process is a running instance managed by the operating system.

When a program starts, the operating system can give the process:

• a process identifier;
• working memory;
• access to files and devices;
• an identity and permissions;
• processor time.

Two processes can run the same program while keeping separate state. Ending one process stops that running instance; it does not delete the program files.

Real example

Your browser is stored as a program. When opened, one or more browser processes run. They may keep tabs isolated, use memory and access files or the network under your user identity.

Mini challenge

Choose one application. Identify what is stored before it starts, what exists only while it runs and what would remain after you close it.

Next stepContinue to Terminal and commands

You now know what stored files and running work are; next you will request observable actions through a shell.