> You wouldn't have true parallelism then, would you? So if you have something, for whatever reason, blocking further processing, the entire computer would loc

> You wouldn't have true parallelism then, would you? So if you have something, for whatever reason, blocking further processing, the entire computer would lock up That doesn't occur because the OS scheduler will eventually pre-empt your thread and swap to another task. You don't really have control over that. All modern OSs use pre-emptive multitasking and there's not a ton you can do to prevent it. (read: anything in the last 30 years, last cooperative multitasking I remember was MacOS Classic (probably like OS7 or so.) Single-core processors were the norm up until 15 years ago, and people routinely ran more than one process on them. Yes, we ran Discord (we called it Roger Wilco or Teamspeak back then) and played music in the background too, without 4 dedicated cores for the background tasks. Yes, in the abstract it would be preferable to have a 64 GHz processor instead of 16 4 GHz processors, because then you can have all that speed devoted to a single task. Context switching is not that expensive (particularly if you have hyperthreads/SMT to soak up the wasted cycles). The physics of transistors make that impossible, but we absolutely would not do any of this multithreading crap if we didn't have to. Single-threaded code is easier to write and usually faster (in terms of less total cycles - multithreaded programs waste extra cycles on synchronization, overhead, spinning for locks, etc that single-threaded programs don't have to).