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Comment by tiberriver256 | Hacker News Reader

Anyone with electrical engineering know if pata vs. sata cables is a good analogy for async vs. sync?

I know parallel ATA cables were all the rage. They had a higher theoretical throughput when compared with serial ATA cables but there was too much cross-talk involved to make it actually faster in the end so now we have serial ATA cables everywhere with much higher throughput than parallel ATA cables could ever achieve.

Should we move back away from parallelism and focus on handling synchronous stuff faster instead?

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PATA vs. SATA is a somewhat limited metaphor; PATA had a number of limitations such as the inability to hot swap hardware as well as using wide ribbon cables that made it largely obsolete. In contrast, both sync and async programming have reasonable applications; we're likely using both for the foreseeable future. The best EE analogy I can think of is using hyperthreading to execute multiple processes on a single core vs scheduling each thread to a separate core, but that's less a metaphor and more of a simplified model of what async vs sync is actually doing.

> Should we move back away from parallelism and focus on handling synchronous stuff faster instead?

Rust already has excellent handling of synchronous computation, given that it can meet/sometimes exceed equivalent performance in C. The problem is when you're I/O or network bound; you can either throw threads at the problem (and by extension throw memory at the problem for the thread stacks) or use async programming.

We're dealing with fundamental limitations of I/O though, which is causing the delays.

I want to write stuff to disk (SSD these days). I can issue a request, then have to wait tens to hundreds of milliseconds (in the average case, the worst case can be far longer) for that request to finish and let me know that my I/O request succeeded or failed. There's no getting around that with present-day technology.

The situation is worse and even less reliable with network I/O. If you are talking to a server in another continent, the speed of light determines the minimum of time I hear back from it, even if it (and all the intermediary network links) are lightly loaded and functioning perfectly.

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