netbsdusers

14 ms·

31.
by netbsdusers 2y ago
NT and XNU never had microkernel origins - Cutler explicitly refuted this at a conference in the early 1990s (if anyone remembers which, kindly share) and NeXTSTEP forked Mach at version 2.5, which was not a microkernel (see https:/&#
32.
by netbsdusers 2y ago
Drivers in userspace is not particularly microkernelly - most of the major monolithic kernels have supported this to some degree or another for years (it is easy in principle, just transmit I/O requests to userspace servers over some c
33.
by netbsdusers 2y ago
For most OSes the amount of code that actually deals in processor minutiae is really quite small. Portable logic makes up the majority. Maybe an exception can be drawn for some very particular OSes like DOS or Windows 9x. So you read a tuto
34.
by netbsdusers 2y ago
Unfortunately this book has the classic fault of osdev tutorials: lots of talking about x86 minutiae, very little osdev. X86 minutiae is not osdev. It is a vanishingly small portion of what even a basic OS has to deal with.
35.
by netbsdusers 2y ago
DHCP services require this ability to receive and send UDP packets on raw sockets, barring a few advanced systems like Solaris that provide them with necessary facilities. Usually they install a BPF module on the socket to filter out uninte
36.
by netbsdusers 2y ago
> Yes I know Ada is not a good fit, but there has already been a Unix-like OS entirely implemented in a derivative of Pascal: TUNIS. Isn't it? There is a very well-developed kernel written in ADA with SPARK and formally verified at
37.
by netbsdusers 2y ago
>"Our operating systems want to do things asynchronously, on their own terms. They'll tell you when they're done. Maybe this is a new era. Maybe making syscalls from 1970s Unix directly is like a remote procedure call to a
38.
by netbsdusers 2y ago
No it isn't. Letting files be poll/select/epoll'd isn't free either. They don't get support for that by magic. A poll operation has to be coded, and this is just as a much a "point of friction" then a
39.
by netbsdusers 2y ago
Five points in reply: 1. Signalfd is a mountain of technical debt. It's not like a file at all. It reads entirely different things depending on which process is reading from a single common open file description, and it interacts with
40.
by netbsdusers 2y ago
They have even cooler capabilities - A single XCOFF library can act as both shared and static libraries
41.
by netbsdusers 2y ago
I am surprised by some of the comments claiming to find it very hard to make an async API out of a sync one. I write a hobby kernel with a profoundly asynchronous I/O system. Since it's nice to have synchronous I/O in some pl
42.
by netbsdusers 2y ago
It's the in-thing at the moment so it certainly attracts attention. Make sure to claim to be "Blazing fast [Rocket Emoji]" in the README too for good measure.
43.
by netbsdusers 2y ago
For kernels (and I suspect database engines might be added to the list, since they seem to have similar requirements to be both scalable and deal with massive amounts of shared state, but I'm not overly familiar with them) is where it
44.
by netbsdusers 2y ago
They lack essential things for a kernel that could be used in production, viz. not kernel panicing during out-of-memory conditions, not an easy thing to retrofit when you have designed without consideration of it. It will probably take a bi
45.
by netbsdusers 2y ago
It's just what we used to call a "layered architecture".
46.
by netbsdusers 2y ago
It's exactly because of licencing that the situation with RISC-V is a world of proprietary SoCs with no consistency, as opposed to the open system that is an x86 PC. (That the ISA is or isn't open is trifling and matters to neithe
47.
by netbsdusers 2y ago
> Rust was invented with an elevator firmware use cases in mind. The inventor happened to work for Mozilla, so it got traction in the lower level parts of Firefox next. TechSpot is referring (without attribution) to an interview the MIT
48.
by netbsdusers 2y ago
> Exceptions are a poor way to signal out-of-memory states. If containers panicked on out-of-memory, we’d enormously reduce the cleanup paths in most functions. What exactly is the difference between a panic and an exception? According t
49.
by netbsdusers 2y ago
> Talking about "technological and political issues" without mentioning any I don't know why you think none were mentioned - to name one, they link a GitHub issue created against the systemd repository by a Googler complai
50.
by netbsdusers 2y ago
> the developers just took the entire TCP/IP stacks from BSD, and call it a day since BSD license does allows for that. They didn't, but I don't know why you're putting a sinister spin on this either way. Of course th
51.
by netbsdusers 2y ago
I think rumours of NT's terminal illness have been greatly exaggerated. There are numerous new developments I am hearing about from it, like the adoption of RCU and the memory partitions. It's not clear to me how processor groups
52.
by netbsdusers 2y ago
I think (but am not sure) that WSL was a consolation prize of the cancelled Project Astoria, the initiative from the dying days of Windows Phone to support running Android apps on Windows. Implementing this with virtualisation would have be
53.
by netbsdusers 2y ago
Filesystem io (and probably more) is not async at the kernel level in Linux. (Just imagine trying to express the complexity of it in continuations or some sort od state machine!) As such io_uring takes the form of a kernel thread pool. Disk
54.
by netbsdusers 2y ago
The second system for Cutler was really Mica - he discusses its outrageous scope in his recent interview with Dave Plummer.
55.
by netbsdusers 2y ago
All kernels execute threads. It's just that very old unixes had a unity of thread and process (and Linux having emulated that later introduced an unprecedented solution to bring in support for posix threads). The other unixes for their
56.
by netbsdusers 2y ago
Posix AIO is just an interface. Windows also relies on thread pools for some async io (I.e. when reading files when all the data necessary to generate a disk request isn't in cache - good luck writing that as purely asynchronous)
57.
by netbsdusers 2y ago
What exactly was "hybrid" about the OS/2 kernel? "Hybrid" has always been basically a made up concept, but in OS/2 it seems especially bizarre to apply it to what's obviously a monolithic kernel, even one
58.
by netbsdusers 2y ago
NT is no microkernel, nor has it ever been. It has always been monolithic.
59.
by netbsdusers 2y ago
Kernel and user threads are distinct on Solaris. The implementation of doors is not by message passing. There needs to be a userland thread context in the server process with a thread control block and all the other things that the userland
60.
by netbsdusers 2y ago
Since bootloaders and operating systems have been a hot topic lately I thought I might post this bootloader which I use myself. It supports its own Limine boot protocol, which has pleasant properties, not least that it provides a sane state

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