[slashclee]

The GPU, bluetooth, wifi, and GPS chips are not running their own operating system kernels. They have firmware microcode that gets loaded when their drivers are loaded, but they aren't running a completely separate dedicated realtime OS.

[makomk]

Some of the common Bluetooth and WiFi chips out there are definitely running their own realtime OS; the Bluetooth chips at least are apparently quite complicated (WiFi hardware designers seems to be less keen on doing everything in firmware).

[pslam]

What do you think is in that "microcode"? Most of what I mentioned is usually running on an ARM of some sort. I count that code as an OS, because it's a pretty narrow definition otherwise.

[slashclee]

Default register initialization values and functions to encode/decode and transmit/receive packets of data do not equal an operating system in my book. Maybe you draw the line at a different level of the stack than I do.

I'm totally willing to be admit that I might be wrong about this, but I wasn't under the impression that Broadcom and Atheros and Intel were using ARM CPUs in their wifi/bluetooth/GPS chipsets.

[pslam]

The missing piece here is that WiFi/Bluetooth/GPS chipsets ARE usually using ARM CPUs internally. GPUs generally run a funky DSP-like core but there's still some kind of OS scheduling tasks and running code to interact with the main CPUs.

The cost of laying down a fully-fledged CPU has reduced to the point where it's simpler and less risky to use an off-the-shelf ARM core (or similar), instead of a big bunch of hard logic combined with coefficient. And most of those CPUs have some sort of runtime, which is an OS, depending on where you draw the line on that.

[tmzt]

Or MIPS or other isas, but still fairly powerful CPUs.

[popee]

> What do you think is in that "microcode"?

Can someone say what this is used for:

$ grep GOOGLE /usr/src/linux/.config

# CONFIG_GOOGLE_FIRMWARE is not set

?

This is not like net interface blob, this is like google firmware and we all know what that means >:-)

[rsync]

The SIM card, however, is indeed running it's own little OS.