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Comment by mtreis86 | Hacker News Reader

Multitasking existed long before computers, so I don't like the title much.

You probably can't cook a meal without multitasking. The author suggests that you are rapidly switching focus, but I don't agree - if you schedule things correctly you can jump from task to task without thinking about it. Eg if you know you need to make a burger with fries and a plate of nachos at the same time you can schedule the tasks based on how much time they take - burger on the grill, fries in the grease, start prepping the bun/plate, get the nachos built and in the broiler, pull the fries and let them drain, plate the burger, add the fries, pull the nachos out, out the window for service. You don't need to think much ahead to get it done while in the process, if you already know the plan and are used to it. Everything has a timer and you just need to move things when the timer says go. Bonus points if the timer is internal.

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We can’t do parallelism, only concurrency on a cognitive level. Think of your brain like the CPU, while your appendages can be thought of as some PCIe connected device. The CPU can send tasks to those and given a well-known pattern it can execute them autonomously (e.g. you can walk without actively thinking about it. But if there is dog shit on the streets you want to avoid you will have to look up and allocate CPU time to the task)

> We can’t do parallelism, only concurrency on a cognitive level.

While that might be through of conscious thought, but there's definitely at least anecdotal evidence to suggest that the brain performs tasks in the background. Think about how many times you've struggled to remember the name of an author, a movie, an actor; only to have it come to you hours later while you're working on something entirely unrelated.

A computer accomplishes tasks by coordinating many subsystems. Not everything is done in the CPU, and the brain is similar. The central unit can make requests of other components (e.g. storage controller), and they go off and do it while the central unit does something else. Only the real heavy thinking/processing happens in the CPU, and that’s always what discussions about human multitasking are talking about. Brains and computer systems work in similar ways.

Even the CPU itself has different processing units which it uses to delegate such tasks and achieve parallelism for tasks which don't have data dependencies

  > Only the real heavy thinking/processing happens in the CPU...
  > Brains and computer systems work in similar ways.

I think that this characterization is pretty simplistic. Perhaps it's useful as a model from time to time, but does not capture the massively complex reality, full of unknowns and poorly understood by science to this day.

Where is this "CPU" in the brain, of which you speak? I suppose the pre-frontal cortex? That zone is generally associated with orchestration/planning, that you mention. But to say that those functions constitute "the real heavy thinking" is a bit of a reach, I think.

It would be like saying the manager does the all the hard work (:

I'm no neuroscientist, but anecdotally, a good portion of my important mental results come from an unknown place — maybe bubbling to the forefront of consciousness when I'm sitting on the toilet, or in a dream. Not when my "CPU is spinning", so to speak.

YMMV.

Don't we breath while we do anything else? That must account for parallelism

I think we can do some limited degree of parallelism. We can walk/run and talk at the same time. We can walk and operate a phone at the same time (albeit more poorly). Our two arms can work in parallel - rub your belly and pat your head. Or, for a better example, driving a manual transmission car -- you can shift gears, and modulate your steering and speed at the same time.

In the mental world, you can also listen to a couple conversations at once with effort.

This level of parallelism feels more like my brain is abstracting two tasks into one. It takes a little practice and then you gain that ability

Interesting observation. Are you saying there IS a feeling of doing two things in parallel that you just don't feel for those tasks? Maybe that is what parallelism feels like.

But on the other hand, would I say that walking is itself parallel because it uses two legs, two feet, and two arms all doing things at once? I guess not.

Another one: turning the handle on my popcorn cooker and hitting microwave buttons to melt butter.

Steering with one hand and changing radio stations with the other.

One that I feel I can't do at all: hit a keyboard key really fast with one hand and hit another one more slowly with another. Unless I treat it like playing drums in a specific rhythm, my fast hand has to stop briefly to let my slow hand hit its key.

The limits of what we can and can't do are not well-explored, nor well-bounded.

For example, there was a fellow (his name escapes me at the moment) who had trained himself to be able to write a sentence with one hand while solving a mathematical equation with the other.

There's a reason why our minds evolved a "unitary" identity or ego, it's evolutionarily advantageous (tautologically, sorry), but it's an illusion. You can "divide" your mind among several tasks (in other words, the brain is not like a CPU, it's more like "the cloud", yeah?) but it's not really as useful as it might seem.

- - - -

(FWIW, my first thought on reading the title was "This person doesn't cook." ;P )

I learnt to do that in elementary school for fun, I would personally do it by doing it concurrently fast enough that the bottleneck was my hand writing instead of the thought, so all I was actually doing in parallel was writing things I had already thought out, so I don't know how much this brings to the concurrency/parallelism conscious thought question.

Human twins are parallel processors, with two identical and independent cores.

What would you call walking and chewing gum?

> You probably can't cook a meal without multitasking

But cooking a meal is a task in itself ( consisting related of subtasks). When cooking a meal it is a good idea to avoid attempting other unrelated tasks such as responding to emails and such as the quality of the original task will decrease

Yeah but is that truly multi tasking? Seems more like an event loop. Which is a form of multi tasking I guess.

In CS, that is more generally called scheduling or pipelining. And they’re forms of queuing theory and capacity resource management. For me, multitasking is the introduction of prioritization into the task queue management. In the above post, there’s a Finish-to-Finish prioritization introduced. We want hot burgers and nachos to complete at the same time or nearly the same time. So, yeah, I’d call that multitasking.

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