Does your system need linux?

Does your system need linux? -- Linux general technology-Linux technology and application information. For details, refer to the following section. Allen's World
I have worked on several products. They use different processors, such as 80186, z80 (old enough), and arm7. All of them use a certain RTOS. In addition to the ecos used in the product 7.7, the other two RTOS are very small systems. They only provide the most basic kernel for multi-task processing. They provide the following: task creation, semaphores, message queues, mailboxes, event signatures, and so on. On top of this, we made a very small file system and then the driver of our own device.

The benefits of using RTOS have been mentioned in many embedded books. When your system complexity reaches a certain level, using the front-end and back-end systems will complicate your work, I understand it in this way.

I have an interesting experience. A system that I once worked on had to be a branch before it was started, a bit like a general bootloader pipeline, and a comparison of a value in flash, then decide which application to start. But they did this: he used the OS! Then, the branch program that writes a few words in the program after the OS is started. I used several lines of assembly code to do the same thing. Why does this developer do this? This is just because there is no obstacle to him. He writes this to other systems and does not need to write arm assembly code. He is a pure C programmer!

Because RTOS does not contain hardware drivers, the application system directly deals with the drivers. What kind of system is Linux? I have not studied these embedded linux systems such as uclinux in depth (rtos I understand as follows: a priority-based preemptible scheduling system generally does not use time slice scheduling) I can only understand the linux kernel 2.6.11 of the development board that I have on hand. He will make the driver into the kernel and provide a unified interface similar to file operations.

I think the biggest benefit of linux is that you can use many ready-made device driver resources. I think there should be the same free resources, including uclinux.

At the same time, none of the systems I have worked on have functions such as mmu and memory protection, and do not distinguish between kernel space and user space. My understanding is: If my system does not need to run third-party software, the software scale is also relatively small, with a single function, why do I need memory protection and complex mmu. But devices like mobile phones or pmp are getting more and more like a pc, and such system mmu and memory protection are necessary. Think about the past, in order to free up a few bytes of space to break the head, and I have a development board with M ram, it is really happy.

My understanding of linux is my rough understanding after reading a little bit of information at the beginning. With my research, I think I will become more and more transparent later. I will write this first today and continue to write my linux study notes tomorrow.