This week we exchanged around what could be the simplest definitions of hard, firm and soft real-time systems. Each of the definitions can cover multiple pages, but at the highest level what could be a one-liner summary? Here are my propositions:

• Hard: if any result is not produced within the deadline, the system is considered as failing

• Firm: if some results are not produced within the deadline, they are discarded and the system is still considered as operational

• Soft: results produced out of the deadline are all considered valid, and the system is always considered functional whatever the delays

What do you think about them? Do you have alternative one-liner definitions for real-time systems that you find better? Please share them, email me!

Happy reading!

Articles

Writing a Really Tiny RISC-V Emulator
It's maybe the tiniest RISC-V emulator around. It is all in one unique function of ~400 lines, but it can run Linux and various executables on it. The tiny C header-only risc-v emulator code is on Github with everything needed to make it run yourself. It's a really impressive work which deserves to be highlighted,

Blue Pill: SysTick programming
It's a straight-to-the-point tutorial on how to use the Cortex M3 24-bit system timer.

Hacking your dishwasher, or cloudless Home Connect appliances
A nice presentation where the speaker describes how he managed to reverse engineered Bosh-Siemens appliance communication protocol to be able to use them disconnected from the Internet.

Peripheral Interaction Without a Linux Device Driver Using Spidev
This article describes how sometimes it is not necessary to implement a kernel space module to drive a peripheral. A good example of how to use the Linux kernel SPI userspace API.

Tools / Libraries

WireViz, Easily document cables and wiring harnesses
WireViz is a little tool very handy to document your cabling and get beautiful visuals from it.

Jobs

Intergalactic, Senior Embedded Software Engineer, 3172 Deseret Dr S, St. George, UT 84790, USA (Open to remote)
Intergalactic is a team of engineers, technologists, designers, mathematicians, and problem solvers committed to a singular idea: reviving the no-boundaries mentality in aerospace. We are a team of the nation’s best, regardless of where we live.

Misc

Taking a good picture of a PCB
We all need these advices, don’t we?