What is a fail soft system? Definition and examples

A fail soft system is one that shuts down non-essential functions when something goes wrong. The system can still function at a basic level. Its basic function may help the user either fix it or take it to somebody who can. We can use the term for a machine, vehicle, or component. We can also use it for computer systems, other systems, and many types of equipment.

With a fail soft system, the computer software, for example, fails selectively. In other words, it selects specific functions to shut down.

However, it keeps the essential or primary functions going. Therefore, as in the case of a computer, the software can continue working, but at reduced capacity.

We can write the term with or without a hyphen, i.e., ‘fail soft‘ or ‘fail-soft.’

Techopedia.com has the following definition of the term:

“Used to describe systems that are designed to terminate any nonessential processing when there are hardware or software failures.”

“Systems in fail soft mode are still able to provide partial operational capability.”

Fail Soft System

Computer Hope says that people design a fail soft system so that non-essential components shut down in the event of a failure. However, the computer system and programs continue running.

Fail soft vs. fail-safe

Do not confuse the term with fail-safe.


A fail-safe is a mechanism in a system or machine that allows it to ‘fail safely.’

For example, lawnmowers have a lever that the user must hold down. If the user lets go of that lever, the lawnmower stops.

That lever is a fail-safe. It is there to protect you and other people. Let’s suppose, for example, that you are mowing your lawn and suddenly lose consciousness. Your hand lets go of the lever.

The machine will subsequently shut down. By shutting down, it is protecting you and other people.

We also call that lever a ‘dead man’s switch.’ Many trains have a dead man’s switch. If something happens to the train driver and they release the switch, the train will stop.

Fail-soft system

This is a system that continues operating at a basic level when there is a fault or malfunction.

Many vehicle spare tires (UK: tyres), for example, have this. They usually come with a speed restriction which leads to poorer fuel economy. However, the driver can get the vehicle to a workshop or home.

In the world of computers, all Windows operating systems have a ‘Safe Mode.’ In that mode, you can do very basic things.