Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Small, smaller, smallest:A tour of the embedded world

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Agenda

● Systems programmer● Embedded Linux● Real-time Linux● Arduino● Real-time operating systems● Embedded without C

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

How I became asystems programmer

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

System software “mindset”

● Reproducibility is hard● Need to unlearn “bad habits”

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Linux KernelDebugging Challenges

● Debugger?● Function tracing?● Logging?● Printks?● “Gut instinct”?

CC-BY-NC-ND neuro https://www.flickr.com/photos/neuro/1052723/

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Linux kerneldevelopment is fun!

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Linux on a Rocket

CC-BY-NC-SA Sarah Sharp https://www.flickr.com/photos/saharabeara/14708892832/CC-BY-NC Pat Joyce https://www.flickr.com/photos/phatcontroller/7467606368/

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Real-time Linux

● Deterministic● Critical software isn't interrupted● RT Linux kernel is pre-emptible

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Linux is… bloated!

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Linux is… bloated!

Linux Weekly News: https://lwn.net/Articles/608945/

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Otter CC-BY Amit Patel

Cheapest Linux Computer - $9

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Otter CC-BY Amit Patel

Linux is too expensive!

CC-BY Bit Boy https://en.wikipedia.org/wiki/Electronic_shelf_label#/media/File:Today%27s_price_for_tea_is..._(96552109).jpg

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Arduino is still too expensive!

● $5 for LilyPad Twinkle

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Arduino

● Tutorials & forums● Build & debug IDE● Hardware abstraction

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Arduino is Embedded

● What is an embedded OS?– board-specific bring up

– hardware abstraction

– C or C++ → byte code

– flash board

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Arduino is Embedded

● What is an embedded OS?– board-specific bring up

– hardware abstraction

– C or C++ → byte code

– flash board

Contiki

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

New Alternatives

● microPython● biosbits.org● Rust bindings to seL4● Zinc.rs● Rust-RTOS

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

SmallestEmbedded Systems

● Do you need an OS?● Bare metal code

CC-BY-NC-SA G A R N E T https://www.flickr.com/photos/youraccount/4864286217/in/photostream/

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Embedded SystemsDebugging Challenges

● good: JTAG● bad: board may not boot :(● serial port output● bus protocol analyzers● oscilloscopes● blinking LEDs● pain of prototype → product

CC-BY-SA Keenan Pepper https://www.flickr.com/photos/keenanpepper/486011046

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

Sarah SharpOtter Tech

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Otter CC-BY Amit Patel

IoT = embedded + connectivity + data

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Otter CC-BY Amit Patel

Welcome to the embedded IoT world!

http://wiki.osdev.org