>>903889 (OP)
>Is software running medical appliances written in a sane, sensible fashion these days /tech/?
No, most of it runs on Windows XP. It varies by countries and regions but most medical computers aren't really secured beyond whatever's enforced on the local network. They depend heavily on blacklisting known bad sites and securing other networking hardware like routers because it's cheaper than upgrading every Windows PC in a hospital. You should also keep in mind that most of their stuff runs on standard Intel hardware in the form of cheap office PCs or embedded industrial boards. These things are usually a decade old at least and don't get proper microcode updates and BIOS patches. Windows XP and 2000 obviously don't get patches so this leaves them vulnerable to stuff like Meltdown and Spectre.
>>903996
>Overall, I'd say that aerospace and nuclear have the highest software quality
The software situation is a lot better for those things. In cars, planes (civilian and military), tanks, rockets, and nuclear power plants, they often run a microkernel RTOS such as QNX or INTEGRITY-178B. These systems have self-healing properties due to their modularity, they never have to go offline even for kernel updates, and device drivers can be run in outside of kernel space for additional security.
But hardware is a different story. The US DoD in particular has had problems in sourcing components for weapons systems, especially for the embedded computer systems inside them. Often times they'll end up with cheap chinkshit parts that are 10-20 years old that have been sanded down and repackaged as new. These parts might pass initial quality control testing but will fail at unknown times in the future within the service life of these pieces of equipment. They're ticking timebombs that could bring entire weapons systems down. This could lead to soldiers and civilians dying if weapons misfire or don't fire at all.
Technology is far from perfect and most things we'd consider super advanced are really held together by duct tape and hanging by a few strands of yarn.