this post was submitted on 20 Aug 2023
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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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Linus Torvalds schools Lennart Poettering on the importance of users (m.youtube.com)
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[–] argv_minus_one@beehaw.org 16 points 1 year ago* (last edited 1 year ago) (1 children)

when it doesn’t work then it’s an ALSA bug and alsa ppl should take the blame (even when it works fine with full alsa, like my audio card).

Well, yeah. PA used ALSA APIs that most applications didn't, which exposed bugs in little-used, little-tested driver code. Nothing implausible about that.

The standard AC97 and USB audio drivers worked fine—I know they did because that's what I was using with PA at the time—but the drivers for more esoteric audio hardware had yet to be debugged, and Lennart couldn't feasibly test and fix all of them by himself because he didn't have the hardware. Others in the community did, and together they fixed the bugs and eventually got PA working smoothly on everything.

And it was designed more like a networking stack then an audio stack.

Of course. PA was specifically designed to be network transparent, same as the X11 protocol it was typically used with.

Sure it was necessary at the time (so that hdmi, and later bluetooth, would work transparently), but the “i know best” attitude hurt its execution.

Ah, but he was correct. He did, in fact, know best. Lennart Poettering brought an end to the clusterf*** that was Linux audio pre-PA. No one else solved the problem until he came along and said “no more,” and I must say I'm appalled at the ingratitude of his detractors.

SystemD on the other hand brought nothing of value. Did way more harm then good.

Nonsense! Before systemd, startup took forever, shutdown took forever, and it was a crapshoot whether shutdown would succeed or hang. Systemd hasn't fully solved this problem, but it's a lot better than what I had to live with in the bad old days.

Also, systemd brings with it a logging system with integrity checking, structured data, and database-like querying. Huge improvement over BSD syslog.

Also also, systemd has proper process supervision, services can depend on devices, unit/global start/stop timeouts, networkd, user session tracking and cleanup, user services, easy-to-use sandboxing, and on and on and on. There's all kinds of useful goodies in there.

[–] gens@programming.dev 1 points 1 year ago (1 children)

Nobody else solved the problems ? Other then hotplugging audio, init thing have been solved many times over. Wanna know the alsa bug on my audio card ? It calls master volume "master center" instead of master. Good progress on pa has been made after its creator long left. And it's done properly only now with pw. PW... where the dev asked for advice from professionals instead of knowing it all. PA is now x11, without the pedigree.

And what about making udev locked down to one init ? I should be greatful for that ? SystemD didn't make computers boot faster the, say, upstart. Logging does not have to be tied to it, as there are even established protocols for it. Etc etc etc

I should be greatful.. for the one true way

[–] argv_minus_one@beehaw.org 2 points 1 year ago

Nobody else solved the problems ?

Nope. Before PA, we had ESD, aRts, and NAS. All of them had horrible latency. They could play a ding at approximately the right time, but everything else was utterly beyond them. They were also mutually incompatible and there was no reliable way for apps to discover which one, if any, they were supposed to use.

Other then hotplugging audio

And multiplexing multiple audio streams to a single input/output device with reasonable latency, and moving an audio stream to a different device, and individually controlling audio streams' volume, and sending audio streams over the network or Bluetooth with reasonable latency, and…

Yeah, no. Linux audio sucked before PA came along. I know it did because I was there, struggling with it.

Wanna know the alsa bug on my audio card ? It calls master volume “master center” instead of master.

Okay? I didn't claim that PA never had any bugs of its own. All software has bugs.

And it’s done properly only now with pw. PW… where the dev asked for advice from professionals instead of knowing it all. PA is now x11

I also didn't claim PA is perfect, nor that some newer, better system will never come along. I claimed that PA is vastly better than what came before it, which is correct, and I have the experience to prove it.

And what about making udev locked down to one init ?

Red Hat chose to cease maintenance of the separate udev and focus its efforts on the systemd-integrated udev. Others took up the task of maintaining a separate udev, and called their fork eudev. I'm not seeing any problem with this.

SystemD didn’t make computers boot faster the, say, upstart.

Upstart expects daemons to SIGSTOP themselves to signal readiness. That is not a sound design.

I don't know if there's anything else wrong with it, as I have never used it myself, but I have yet to hear any well-reasoned explanation of how it's better than systemd.

Logging does not have to be tied to it

It isn't. You can still use a syslog daemon with systemd if you want.

as there are even established protocols for it.

Yes, and have you ever tried to implement them? I have. They suck.

  • Extremely easy to format or parse incorrectly.
  • Non-extensible, leading to a proliferation of dialects, making parsing log records a minefield.
  • No way to include line feeds or other control characters in a log record.
  • There are two different, mutually incompatible protocols, only one of which is described by IETF RFCs. The RFCs describe the protocol used for logging on another machine. There do not appear to be any formal standards for the local logging protocol used on /dev/log. There isn't even a specification saying /dev/log exists at all.
  • No structured data, outside of an obscure RFC that has, as far as I can tell, zero implementations.
  • 1024 bytes max per log record. If you want to include a stack trace with your log message, too bad, not happening.

And that's just the log record submission protocol. The storage format has all of the above problems except the one about /dev/log, and several more:

  • The only real standard for how log records are stored is that they're delimited by line feeds. That's it. Everything else is configurable and therefore unpredictable. Parsing them reliably is basically impossible.
  • If the syslog daemon has a hiccup, log records can be smushed together without a line feed delimiter, making them extra-impossible to parse. There is no checksum or length field with which to automatically detect that this has happened.
  • Log records are typically separated into numerous different log files. Don't know which one your program's log records are ending up in? Here's grep; good luck.
  • Owing to the aforementioned parsing difficulties, there is no reliable way to filter logs by program, by date, etc. Here's grep; good luck.
  • The systemd service (or equivalent) from which a log record originated is not recorded in the log. Better hope your program doesn't use a different name than the one you expect it to use. I know of at least one that has this behavior: cron.
  • There is no record of whether a log record was generated during the current boot or the previous one. Want to only see log records since the last reboot? Here's grep; good luck.
  • Did I mention there are no checksums? Because there are no checksums.

This may have been acceptable in the 1980s, but it doesn't hold a candle to the systemd journal. Good riddance.

I should be greatful… for the one true way

You should be grateful for software that is vastly better than its predecessors with no significant drawbacks, yes.