What 'dependency' means in Unix init systems is underspecified

Re:What 'dependency' means in Unix init systems is underspec... by Too on Sunday October 28, 2018 @02:50AM (#18319446)

With that method you can only express 1-1 relationships. Usually in real systems you have N-M. Your method is also linear, it has to wait for one line to complete before running the next even though they don't depend on each other. Parallel execution is one of the reasons systemd boots so much faster than it's predecessor.

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Re:What 'dependency' means in Unix init systems is underspec... by rleigh on Sunday October 28, 2018 @06:59AM (#18320111)

Except that it doesn't, in practice, boot any faster at all. Most times I measure it, it's actually slower.

And by the way, its predecessor, with insserv and startpar, also supported parallel execution of init scripts.

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Re:What 'dependency' means in Unix init systems is underspec... by Too on Sunday October 28, 2018 @08:11AM (#18320293)

Not familiar with insserv or startpar but there is a difference between supports and supports. Most systems support everything in the sense that it's turing complete but it should be easy to do it without creating spaghetti also. Not saying systemd is the best or only system that can do this, it was just an example, but older ones usually make it very messy.

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Re:What 'dependency' means in Unix init systems is underspec... by rleigh on Sunday October 28, 2018 @08:56AM (#18320397)

It was supported for many years by the LSB standard init headers which were used to compute a dependency graph for parallel execution.

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