BaSzErr - blog:2021:06:04

2021-06-04_-_kelly_johnson_s_14_rules

anonymous@undisclosed.example.com (Anonymous) — Tue, 15 Jun 2021 20:09:41 +0000

2021-06-04 - Kelly Johnson's 14 rules

you may not recognize the name of Kelly Johnson but you're surely aware of skunk works. my long due note is about Kelly Johnson's 14 rules for managing projects. while some of these are very specific to military projects, it does play along with my view on how to organize projects, well:

organize small, autonomous teams, consisting of true experts
pay them well, to keep money out of the focus
pay for results, not number of ppl being supervised
keep bureaucracy away, as it kills innovation
keep work environment flexible and open for a change

2021-06-04_-_mastering_openscad

anonymous@undisclosed.example.com (Anonymous) — Tue, 15 Jun 2021 20:09:41 +0000

2021-06-04 - mastering OpenSCAD

i recently came across a mastering OpenSCAD book. it's free in online form or available for purchase in paperback. it made a great reading. even though i use OpenSCAD for well over half a decade now, i still managed to learn some new tricks. i wish i had this on my table back at the time i was starting my OpenSCAD adventure! happy reading! :)

2021-06-04_-_software_in_space_by_spacex

anonymous@undisclosed.example.com (Anonymous) — Tue, 15 Jun 2021 20:09:41 +0000

2021-06-04 - software in space by SpaceX

if you were on this year's emBO++ conference, you already know that space industry if governed by the “YOLO rule” – You Only Launch Once. space is interesting because it is so remote… and also because it is so difficult. if you screw sth up, it is very hard or impossible to send out a guy with JTAG to reflash the whole thing. ;)

i recently came across an interesting reading about software for space industry, i.e. how SpaceX is doing that. while the material is targeting wide audience (thus is fairly general), it still makes a good reading. it comes in a series of 4 blog entries:

2021-06-04_-_the_design_of_everyday_things

anonymous@undisclosed.example.com (Anonymous) — Tue, 15 Jun 2021 20:09:41 +0000

2021-06-04 - the design of everyday things

while listening to on of the episodes of hackaday's podcast, Eliot Williams mentioned a book: The Design of Everyday Things. it caught my attention immediately. when i finished reading i concur with Eliot – it should be an obligatory reading material for each engineer. :) just have a look at the cover – while the item looks nice, the designer clearly have though of how to actually use it in practice (not to mention ACTUALLY using it)… and this is how many interfaces are created. this is why it is important that engineers are interested in the field, they are working.

btw: i recently asked a UX designer about the book and he smiled saying: “oh yes – it's our bible!”.

btw2: 1st chapter of the book is called “psychopathology of everyday things”. enjoy your reading! :)

2021-06-04_-_very_much_invalid_self-signed_certificate

anonymous@undisclosed.example.com (Anonymous) — Tue, 15 Jun 2021 20:09:41 +0000

2021-06-04 - very much invalid self-signed certificate

X.509 certificates are not issued for private networks (as these are not unique). while it does make sense, it often means that the only secure way of deploying HTTPS in some organizations is to issue a self-signed certificate. it is also a very often practice in R&D, for temporary/test/dev instances.

R&D setup in one of our test deployments was no different here… except it did not worked with some clients. it however did work just fine for others. it took some digging into the subject, to find out that that fact it worked for some clients was a bug in and older OpenSSL library. the thing is that self-signed certificate must have “CA” flag set to true, in order to be valid (i.e. it must form a 1-element chain of trust). if it does not, technically the certificate is invalid.

you normally do not see this, since OpenSSL by default makes self-signed certificates marked as CAs. in our case the issue was that some1 user non-standard settings, when creating certificate, and missed that particular detail. since it worked with his browser, all looked good at a glance. well – in any system, that is complex enough, there will always be some discrepancy between specification and implementation.

2021-06-04_-_wifi_roaming

anonymous@undisclosed.example.com (Anonymous) — Tue, 15 Jun 2021 20:09:41 +0000

2021-06-04 - wifi roaming

there is a thick, concrete, steel-reinforced wall running though the middle of my flat. it has been the same on my previous flat. while it does not matter much day to day, one thing that used to be a bit annoying was wifi signal strength. with my AP set to 100% power, signal was just enough to browse the web, on the other end of the flat. that was 2.4GHz of course. you can pretty much forget about (usable) 5GHz. while you can buy more powerful APs and more sensitive end-user devices, “bugger hammer” was not the option for me.

it turned out there is a good, standard-compliant solution to have multiple APs at home, serving the same network, with IEEE 802.11r-2008 wifi roaming. it is not exactly the same thing as roaming in cellular network – it is still very client-dependent. it does however work with any reasonably modern devices. i.e. my 5+ years old phone sucked when it came to wifi roaming. however it was kind enough to finally break and my “new” (2-3 years old) device work like a charm. same for all tablets and laptops. OpenWRT does support it out of the box. if you're in the same situation i am in – give it a shot. it does not break compatibility and allows to keep internet running, while roaming ones home. ;)