Math Is Hard – OpenBSD Stories
miod.online.fr
miod.online.fr
Early versions of Microsoft Flight Simulator included a handler for the divide exception, which adjusted the result to +/- "infinity" (for a 16-bit signed integer, 32767 or -32768). The rest of the code relied on this in order to work correctly, and it was more efficient to take advantage of the processor's microcode doing this check rather than coding it explicitly before every division.
So even if it doesn't make mathematical sense, being able to continue after this type of exception is a useful feature to have.
>(and if you ignore SIGSEGV, it is considered perfectly acceptable that your program spins in a SIGSEGV loop until you kill it.)
This, on the other hand, shouldn't ever be acceptable. If a fatal-by-default signal is just ignored, it should always terminate the process.
25 years ago there was an avalanche of new operating systems and if somebody asked me at that time, I was sure we will have much better operating systems in the future using fresh ideas.
I am not saying UNIX is bad, just that I would like to see some advancements in the OS area, beside improving UNIX kernels and APIs.
https://doc.cat-v.org/bell_labs/good_bad_ugly/
Do you have a link?
I initially thought the containerization movement of the early 2010s would be the first step toward redefining the OS—a way to finally slim things down. Instead, it just became a more efficient way to pack up the same baggage. We created a "reduction" in deployment complexity, but we haven't seen a continued effort to use those tools to actually change the paradigm.
I expected vertically integrated systems to become the norm by now—where building an executable would be an experience similar to containerization, but resulting in a lean, data-centric unikernel.
Instead, we are burning CAPEX on YAML sidecars in K8s clusters and N-tier abstractions that exist solely due to the large heterogeneity of the deployments that they never should have entered in the first place. We are spending more energy on the friction between layers than on the actual business of computation.
I was hoping for a return to sanity with the DBOS [1] research, looked like an attempt to rethink systems from first principles. But it seems that effort hasn't fully kicked off in the way the industry desperately needs.
Ask yourself which one is easier to diagnose and debug.
"When running on real hardware console output will be over serial."
> 1.
Seems to be a variant of "0" running on "Odroid-C4."
> 2. https://genode.org/
This one looks more polished.
Most of the people today are afraid to build OSs so they stick to virtual machines. An OS without drivers is not an OS.
Which ones? I can only think of maybe Microsoft Singularity in 2003, and hobby OS Syllable. Neither were particularly innovative - the managed code thing had been done before with Inferno, and Syllable was heavily inspired by BeOS.
edit: not to dismiss kernel programmers, you people are awesome!
It is so easy to learn x86 assembly that way, and actually understand WHY BIOS was so important.
Os development is so easy nowdays with internet forums...
Was there ever a source drop for VMS on vax? Probably hard to impossable to figure out if not
apparently some at some point?