> Seriously now, did you honestly think that he would say to use xinetd over systemd?

No... but I thought he might be able to pretty adequately explain how systemd exploits socket activation and contrast it with xientd....

> Do you honestly believe a developer will advocate the use of a competing piece of software over something (s)he produced?

Well, I've certainly done it, so it is possible, but I wasn't referencing him as a persuasive voice... Even if I was, that'd be such a flawed and pathetic argument...

> Unless you don't feel like replacing small, simple, easy-to-use, well-tested xinetd with the 200K-line pile of C code that is systemd.

You might want to look at the code. The socket activation logic is a pretty clean & tight ~90K chunk of code in a handful of files... and for the record, xinetd isn't that slim, with nearly 25K lines of code spead over well over a hundred files, and that's if you only count the C source files.

> As you can see, "socket activation" is by and large a marketing gimmick.

Sigh... I can see you didn't read the article. The implementation differences aren't terribly different, and Lennart already made your points for you... Systemd does have some little tweaks that open up a bunch of different worlds of advantages.

> Sir/madam, have you ever written an Internet-facing daemon?

Yes, but of course, in this context we're primarily focused on AF_UNIX sockets...

> Obviously the bulk of the RPC logic lives in a shared library. You know, a logically distinct module that can be independently installed, loaded once, and independently maintained.

it's very common, for example, for web apps to have a separate process that parses and validates inbound HTTP requests RESTful requests before passing them on to the main application process. You can and do run web apps that are directly exposed to the Internet, but nobody suggests this is to make the request processing logic more modular...

> You seem to want to replace the RPC shared library with a separate process. Not only will this make create a performance bottleneck, but also it makes it a single point of failure. If it crashes, all your daemons lose their connections. This is obviously highly undesirable, especially on servers.

I see you are familiar with Erlang. ;-)

You raise a good point. Often to reduce failure rates people employ load balancer that work with various HA protocols to avoid losing connetions. What do load balancers do again? Oh yeah, they are separate processes receive in bound RPC requests, parse and validate them, attempt to mitigate any in bound attacks before routing and forwarding them to the application itself...

And of course, a lot of web applications are largely front ends to a database, which means they themselves are processing RPC requests, formatting, validating and transforming them before forwarding them to a database for execution...

..and let's not get started about middleware... ;-)

> You seem to want to replace the RPC shared library with a separate process.

No. I really don't. I'm just pointing out that if you are looking for small, modular and loosely coupled components that are fairly resilient, it's not like someone is going to say that moving a component form a shared library to a separate process is going to get critiqued on the basis that it intrinsically makes for more tightly coupled code.

Or wait, are you suggesting that systems where all these libraries are rolled up in to one process would be more modular? [looks at critique of how systemd puts too much stuff in to one process...]