I just bought a Raspberry Pi 2 B to so I can learn more about programming.

I noticed that there are a lot of questions about running real time software on the Raspberry Pi, such as this one:

Is it possible to run real time software?

My question is, why are there problems with running real time software on the Raspberry Pi in the first place? What are the implications of this?

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  • Hello and welcome to RaspberryPi SE. I think this question is quite broad and therefore hard to answer. Could you be more specific about the issues you need answered? – Ghanima May 19 '15 at 20:17
  • Sorry if you feel it is too broad. I just feel like I am missing something here and I am trying to learn. Would it help if I mention that I wanted to do a project involving sensors and data collection? – CCovey May 19 '15 at 20:42
  • If the answers you get are helpful to you I shall be fine with it ;) – Ghanima May 20 '15 at 9:25

It really depends on what you want to do. A real-time system usually means that a system's response to stimulus is guaranteed within a specific timeframe. A simplified example is an immediate response, rather than a queueing.

Most operating systems aren't designed to work in real time; there's very little reason for them to be. If you don't have a real time OS, it's very difficult (if not impossible) to run real time software. The primary way to deal with this is to use hardware that's dedicated to the task, and then have your operating system interface with it.

For the purposes of learning general programming, you shouldn't need to worry about this unless you have particular real time problems in mind.

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Real-time is a term which seems to have lost all meaning due to incorrect overuse. A lot of people seem to think it's a synonym with fast.

A real-time system is a system which has real-time requirements. A real-time requirement is typically expressed as follows:

From the time an input event happens at the system boundary to the time all needed outputs are generated at the system boundary less than x seconds will have elapsed.

Where x may be nanoseconds to days depending on the particular requirement.

You would need to examine each requirement in turn to see if the Pi could do the job.

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