How Do Computers Work? (At Most Basic Level)

[kyphysics]

It's late/early...I'm procrastinating on a project...

Thought I'd ask a "dumb" question to satisfy my curiosity. I know computers have hardware (physical machine) and software (from the operating system to other programs/apps that can be downloaded onto the hardware to perform certain functions)...

But, how exactly does the computer "read" or interact with that software? Feel free to treat me like a 3rd grader, who is dumber than a door knob and ignorant of everything computer-related.

Once someone inserts a piece of software into the hardware to be downloaded and run it...what the heck actually goes on after that and how does the machine "process" the software to do the stuff it is designed to do?

 

[jack action]

Switches ... It's all about switches.

As soon as you turn the computer on, the current goes through pre-defined circuits and ends up doing an action. With additional software, you are setting the switches differently to "customize" the output.

The mechanical equivalent would be the valve body of an automatic transmission, which is really a very simple hydraulic computer.

 

[hutchphd]

I am still fond of Forrest Mims.

https://doc.lagout.org/science/0_Co...igital Computers (1978)(Radio Shack)(pdf).pdf

Not a new book

 

[anorlunda]

May I suggest the videos of Ben Eater
https://www.youtube.com/c/BenEater

He shows by building how to make a computer, how to write software, and
how to execute that software.

 

[Mark44]

It's all about switches.

... or gates, such as AND gates, OR gates, and others. This wikipedia article shows a couple of animated GIFs of very simple CPUs that are able to add two bits - https://en.wikipedia.org/wiki/Adder... often,add 8, 16, 32, etc. bit binary numbers.

More capable CPUs can be designed and fabricated by chaining together collections of the kinds of devices depicted in that article.

 

[Mark44]

Once someone inserts a piece of software into the hardware to be downloaded and run it...what the heck actually goes on after that and how does the machine "process" the software to do the stuff it is designed to do?

The answer is probably more complicated than a 3rd grader is able to understand beyond a very cursory level. For the sake of simplicity, let's assume that said computer is equipped with an operating system and file system. When you click a executable file icon or type the name of the executable file in a command prompt, the operating system (OS) loads the file into memory. The computer's central processing unit (CPU) starts executing the machine instructions that are contained in the executable file, starting from what's called the file's entry point. The CPU continues processing the instructions in the file until the program ends, either because of the logic of the program or due to the user ending it.

 

[phinds]

HOW-COMPUTERS-WORK

 

[Mark44]

HOW-COMPUTERS-WORK

This 9th edition in hardcover is over $1000 at Amazon. The 10th edition is much more reasonable at $31.40 - https://www.amazon.com/dp/078974984X/?tag=pfamazon01-20

 

[phinds]

This 9th edition in hardcover is over $1000 at Amazon. The 10th edition is much more reasonable at $31.40 - https://www.amazon.com/dp/078974984X/?tag=pfamazon01-20

GGAAAACCCKKK ! I didn't even notice the price, just cut/pasted the link from my Amazon orders. I bought it last year for a young relative and it was $16.00

 

[Mark44]

@kyphysics, why the skeptical emoji on my post #8?

 

[jack action]

... or gates, such as AND gates, OR gates, and others.

But logic gates are really just a bunch of switches:

LOGIC GATES USING SWITCH
AND GATE USING SWITCH

OR GATE USING SWITCH

NOT GATE USING SWITCH

And when done with transistors, it looks like this:

 

[Mark44]

But logic gates are really just a bunch of switches:

But switches are just a bunch of molecules, and molecules are just a bunch of atoms. It just depends on how far down you want to go to explain the workings of a computer.

 

[kyphysics]

@kyphysics, why the skeptical emoji on my post #8?

$1,000

 

[TheLochnessMister]

When I was a teen I read Code by Charles Petzold and The Definitive Guide to How Computers Do Math by Clive Maxfield. These both evolved my interest in fundamental computers such as Ben Eater's 8-Bit computer.