I'm confused.. so Wi-Fi chips run OSes inside them now?
After the memory controller, bus bridges, GPUs, and DMA controller, it's probably the largest one.
Probably best to distinguish between processing-heavy and throughput-heavy; apart from the GPU, all those are throughput-heavy but do very little to the data, and I think would not normally have a recognisable processor or an OS. There's the additional problem that they're required to boot, so nowhere convenient to load the OS from unless you scatter SPI flash across the board.
GPUs on the other hand have a full task-switching operating system.
I would be surprised if the faster bus and memory controllers had it (because of latency problems). I would expect something like it on a USB controller, GPU, network or disk interface. I really have no idea what to expect from a DMA controller.
> PCs are just several embedded devices in a trenchcoat
While you can achieve the same abstraction in hardware it’s much easier and cheaper to simply pick a small micro controller and do all the black magic you need in software especially since the flash on some of these cards can be really really bad as it’s often the lowest grade flash or worse recycled memory that ends up being used which means you end up with chips that are 50-80% defected so the controller ensures that these sectors/cells aren’t used.
> "hreadX provides priority-based, preemptive scheduling, fast interrupt response, memory management, interthread communication, mutual exclusion, event notification, and thread synchronization features. Major distinguishing technology characteristics of ThreadX include preemption-threshold, priority inheritance, efficient timer management, picokernel design, event-chaining, fast software timers, and compact size. The minimal footprint of ThreadX on an ARM processor is on the order of 2KB"
ie it's generic code that gets built into a unikernel-style image with the device-specific code that actually implements the various tasks required of a wifi controller.
I haven’t seen any evidence that any of these MC does anything beyond that.
Saying this without any animosity, but you would probably be interested in reading about the history of operating systems. Desktop OSes are a (very visible) minority, and it's the opposite way in my opinion: a desktop OS is an OS + a large suite of tools + a shell.
It's literally something that operates the system so that every program written doesn't have to handle all the low level IO, that enables task management, etc.