And the debugger is here: https://github.com/oxidecomputer/humility/blob/master/cmd/ri...
I also gave a talk at this year's Open Source Firmware Conference that covers a bunch of debug strategies: https://www.osfc.io/2023/talks/unplugging-the-debugger-live-...
(conference videos aren't online yet, but should be posted early next week)
I design them in Monodraw, pass it through a janky converter I wrote that converts text into a json grid of characters. I then render a number of layers that get combined, which is a mix of the static art layer, and others generated from functions that spit out a similar cell based frame.
If you're interested: https://gist.github.com/benjaminleonard/c913ddbf23fe7a70f9c2...
And for what it's worth there's this ASCII game: https://twitter.com/StoneStoryRPG
So, Humility is like MC/DC?
https://en.wikipedia.org/wiki/Modified_condition/decision_co...
1. The state or quality of being humble; freedom from pride and arrogance; lowliness of mind; a modest estimate of one's own worth; a sense of one's own unworthiness through imperfection and sinfulness; self-abasement; humbleness.
-- Webster's 1918 Dictionary
Our avionics software was originally spec-ed to not NEED a debugger it was to be of such high quality, but the designer added break point op-codes in the VM anyway. I guess he was aware of the concept of humility, too. ;) Like humor, humility seems to be in short supply these days.
People claiming to be humble are all over the fucking place these days and Millennials are addicted to wanting that word like crack. The result is that the people bragging about being humble the most are usually narcissists.
Hmm...maybe I should have referenced:
https://en.wikipedia.org/wiki/Sacred_cow_(idiom)
> The motto of the satirical magazine The Realist was "Irreverence is our only sacred cow".
Humor does seem to exist today, it just has a narrow band-pass filter, with apparent focus on "organic" product marketing.
When I see the concept of "extremely high quality" applied to software in the aerospace domain, I tend to think of methods like formal proofs and "semi-formal" methodologies like DO-178C (including MC/DC, not as a tool, but as a critical sub-process). It does appear that Humility adheres to some traditional ideas used in even "safety conscious", real-time embedded work:
> However, Hubris may be more interesting for what it doesn't have. There are no operations for creating or destroying tasks at runtime, no dynamic resource allocation, no driver code running in privileged mode, and no C code in the system. This removes, by construction, a lot of the attack surface normally present in similar systems. [1]
Oxide surely didn't invent all these concepts, we were applying some of this (using C) in the early '90s on human-safety-critical embedded projects, and they were most likely used before that. The attack surface eliminated is more than just security, e.g. even self-induced "attacks" from task priority inversion. Maybe the concept of applying them to rack mount servers is novel, but I have no experience there. Techniques like DO-178C go farther and do things like trace requirements to object code and strict coverage criteria.
When you are considering where Hubris/Humility might be applied in aerospace, also note that it would most likely be denied at the proposal stage of talking to a regulatory body like the FAA if you said, "The methodology for our brake controller is cloning a Github repo written by 100X S/W engineers in the Rust language, then modding that to fit." It's a process you have to follow in a documented fashion, from the start. Who knows--I certainly don't know everything--if you do have a identify reproducible process that improves S/W quality, the FAA might be interested.
And as far as eliminating debuggers goes, Boeing did actually do a joint academic/industry project on a zero-bug reduced (subset) Ada compiler (Zbra), which itself would be qualified as a tool instead of the more laborious process of mapping requirements to object code directly. [2]
In the spirit of humor shown on this topic, I would suggest considering a reduced subset of Rust called Iron. :) Regards, and best of luck!
[1] https://oxidecomputer.github.io/hubris/
[2] http://www.sigada.org/conf/sigada2002/SIGAda2002-CDROM/SIGAd...
* Memory access is protected, but addresses are not virtually mapped. The lack of paging of course ties strongly to the inability to dynamically add tasks.
* They wish they could have read-only shared libraries (viable since there's only one address space) so they could truly be shared, but the current ecosystem assumes mutability is possible (even though in Rust mutable globals are rare).
Can't wait to read its source code, I was curious since reading this thread[2].
[1] https://github.com/oxidecomputer/helios (if this is not found for you, we're in the same boat)
I would expect nothing less from that crew. They did amazing things at Sun Microsystems, Inc. (RIP), and they continue to do even greater things now.
https://github.com/oxidecomputer/hubris
And, that one underscore-delimited folder name in this repo just catches the eye, huh?
With respect to Humility, I am going to resist the temptation of pointing out why one of those directories has a different nomenclature with respect to its delimiter -- and just leave it at this: if you really want to find some filthy code in Humility, you can do much, much better than that!
[0] https://github.com/oxidecomputer/hubris/commit/651a9546b20ce...