What does this numbers in bracket mean?

Question

I don't have 14 firefox opened but task managers showing "14":

What does this numbers in brackets mean?

Answer 1

Many modern applications can use multiple "processes" to separate and segregate tasks that they need to perform.

The do this for multiple reasons

• Performance. They can achieve more work than a single process. For example one process can be rendering the page on screen while another is decoding images, downloading things, or generally handling network communications. All of these can happen independently and at the same time rather than using a single process that can only do one thing at a time.
• Reliability. If something goes wrong in one process then only that process might crash. The "host" process can then simply reload that one process and start it again. A single tab crashing won't take down the whole browser.
• Security. Processes can be sandboxed from each other and sensitive information in one process is kept away from all other processes, only information like images and network data is shared when needed.

The "(14)" is how many processes Firefox is using.

If you want to learn more about how Firefox does it you can see their Electrolysis Web page which describes their efforts to convert their browser engine to using multiple processes.

Answer 2

Firefox (like any program, but especially browsers) do a lot of stuff in the background for a webpage to load, so each process going on inside of Firefox is a separate process showing in Task Manager.

For a specific breakdown of the 14 processes, you can open Firefox's own Task Manager (Menu > More Tools > Task Manager, or the Shift+Esc keyboard shortcut), and it will list you each process and what it is: