I've been thinking about it for a while to try to transition from a mechanical engineer to a software engineer but are all the interviews as miserable as HN makes it seem? I feel like these interview structure is a form of deterrent. I had a quick call with one of the recruiters from Apple for a hardware engineer position. He said the interview will take about a week and needs about a month to prepare... I didn't call back because it doesn't even seem reasonable to me.

I've interviewed many times (mechanical engineering positions) for big companies (10K employees+) to small (<50 employees) and they're usually a one day remote and one day on-site interview. There would be a couple of technical questions and some technical discussions but nothing like, solve this Navier-Stokes equation for creep flow from your memory. I don't think any competent manager would even ask that to me.