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Meet Linux's Little Brother Zephyr, a Tiny Open Source IoT RTOS (linuxgizmos.com)
DeviceGuru writes: The Linux Foundation has launched the Zephyr Project, to foster an open source, small footprint, modular, scalable, connected, real-time OS for IoT devices. The Zephyr Project's RTOS implements both a small footpoint microkernel and an even tinier nanokernel, and is the result of Wind River contributing its Rocket RTOS kernel to the Zephyr Project. (Wind's Rocket RTOS will now become a downstream commercial distribution based on Zephyr sources.) To get a sense of Zephyr's benefit, its nanokernel is said to be able to run in as little as 10KB of RAM on 32-bit microcontrollers, whereas a minimalistic Linux implementation like uClinux needs upwards of 200KB. The Linux Foundation hopes to see cross-project collaboration between the Zephyr and Linux communities. Technical details are at the Zephyr site.
I've been seeing piles and piles of new chips that come with integrated 32bit arm cores, flash, and ram. And they're dirt cheap. Nowadays it seems pretty much all non-trivial chips include an ARM core with enough storage and ram to run circles around any desktop computer found in the 80s or even early 90s.
About 9 dollars shipped for a hacker-friendly breakout board based on the NRF51822.. And that's not just a processor. It's a Bluetooth 4.0 radio that supports bluetooth LE and all the other bells and whistles. 15kb ram, 256k flash, and whole mess of features to get data in and out. Seems right in the footprint for this little OS.
Add bluetooth and a fairly powerful "micro" to any project for less than 10 bucks.
http://www.ebay.com/itm/-/400970594571
Development board for the above module:
http://www.ebay.com/itm/-/400967553827
Browse that seller of the above items and be amazed at the absolutely insane amount of dirt cheap hacker friendly electronics you can get shipped from china for just a few bucks. Granted specs may be exaggerated and you'll want to do a little poking and testing on your own.. But that's half the fun, isnt it? :)
I guess the definition for IoT devices is something that is "a device not primarily used for computation that can be controlled/accessed through the Internet". For example a washing machine, a watch, a fridge, heat controllers, windows (the physical ones that you can open), smart meters.
IoT then also refers to a time where these would become extremely commonplace, in the sense that many types of devices are connected to the internet in everyones home/work/public areas.
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
What makes a device an IoT device?
If it floats on a cloud, runs off the willpower of app developers and is a security and privacy nightmare. Then it's IoT.
-SR
IoT devices will typically only have a few kB of RAM, so yes, it does matter. As a data point, I'm working with an ARM Cortex-M0 processor at the moment and it has a grand total of 128kB program memory (flash, so you can't use it for read/write data storage) and 16kB RAM. This is an entirely typical processor for this sort of IoT application.
Take a look at the specs on most microcontroller boards out there and you'll feel very differently about saving 190KB. In some cases that's more memory than the board comes with.
* TI Tiva Launchpad - 32 KB - http://www.ti.com/tool/ek-tm4c123gxl
* ST Discovery Board - 190 KB - http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/PF252419
* Olimex STM32E407 - 192 KB - https://www.olimex.com/Products/ARM/ST/STM32-E407/open-source-hardware
* Arduino 101 - 24 KB - https://www.arduino.cc/en/Main/ArduinoBoard101
* Intel Galileo - 512 KB - http://www.intel.com/newsroom/kits/quark/galileo/pdfs/Intel_Galileo_Datasheet.pdf
I could go on, but you get the point.