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No. It would be more accurate to say that is is a lot more work to reimplement a hard realtime embedded RTOS from scratch, when you have a nontrivial applicatio

No. It would be more accurate to say that is is a lot more work to reimplement a hard realtime embedded RTOS from scratch, when you have a nontrivial application that needs features like tasking, synchronization, IPC, memory virtualization etc. That is probably not Linux, but going bare target every time you have a new application and platform with hard realtime requirements would be a huge mistake. > you use standard library abstractions to get features that you would normally get from the OS They don't come ex nihilo. There are a lot of "standard library" APIs that are dependent on what would ordinarily be called an OS. > Then, if you want to run a bunch of these things, you run them in efficient hypervisor systems like Xen. This is often, if not usually, the wrong level of abstract for either application architecture or efficient resource usage.

wyager 10y ago
>features like tasking, synchronization, IPC, memory virtualization etc. If you use any of these features in a hard-realtime application, you are making multiple huge mistakes. > They don't come ex nihilo. Did I suggest they did? You don't have to believe me; look up the projects I mentioned. > This is often, if not usually, the wrong level of abstract for either application architecture or efficient resource usage. This is because current tools don't support developing software in this way. Hence the variety of in-development projects to facilitate it.
Animats 10y ago
There are intermediate steps between bare metal and Linux, and they're widely used in the embedded world. See Wikipedia for a long list. I just noticed that there's now CapROS for ARM.[1] This is a capability-based secure operating system for small machines. It's a successor to EROS and KeyCOS, which had a good track record for security and reliability. Unfortunately, there's very little documentation. Somebody could bring that up to usability for ARM embedded devices and make money selling support to IoT companies. [1] http://www.capros.org/ http://www.capros.org/

wyager 10y ago

>features like tasking, synchronization, IPC, memory virtualization etc. If you use any of these features in a hard-realtime application, you are making multiple huge mistakes. > They don't come ex nihilo. Did I suggest they did? You don't have to believe me; look up the projects I mentioned. > This is often, if not usually, the wrong level of abstract for either application architecture or efficient resource usage. This is because current tools don't support developing software in this way. Hence the variety of in-development projects to facilitate it.

Animats 10y ago

There are intermediate steps between bare metal and Linux, and they're widely used in the embedded world. See Wikipedia for a long list. I just noticed that there's now CapROS for ARM.[1] This is a capability-based secure operating system for small machines. It's a successor to EROS and KeyCOS, which had a good track record for security and reliability. Unfortunately, there's very little documentation. Somebody could bring that up to usability for ARM embedded devices and make money selling support to IoT companies. [1] http://www.capros.org/ http://www.capros.org/