A computer without a program running on it is just a hunk of hardware.

Hardware is anything that's well, hard, like a desktop, tablet, or smartphone.

In order for a piece of hardware to do anything, it has to run programs.

In order for

programs to work, they need to be written in a way a computer can understand.

This is where binary and data come into play.

Programs themselves and what you create when using them are all stored as data,

which are just a lot of binary digits, ones and zeroes.

[SOUND] One of the first programs you see when you turn on [SOUND] your computer is

the operating [SOUND] system.

The job of the operating system is to help all [SOUND] other computer programs work

by handling the messy details of controlling the computer's hardware.

[SOUND] The operating system is the core software component of a computer and

provides an interface between the [SOUND] hardware and the software.

Say, for example, you wanted to open an application.

You would have to click on it either with your mouse or tap it with your finger.

That click or [SOUND] touch is called an event.

[SOUND] When you send that click through your mouse, touchscreen or

keyboard, it's the operating system's job to watch for that event.

[SOUND] When you click an application, part of the operating system's job is to

stash the mouse click's information in memory until it can be processed.

In addition to storing events as data, applications are data, and what's inside

those applications are data, like documents, photographs, video, and music.

In order to save all this data,

your computer uses a few different types of electronic storage depending on

the priority and type of data you want to store.

To store data into memory in an efficient way,

there are a few different types of memory to choose from.

RAM and virtual memory are temporary storage areas.

And a ROM and hard drives are permanent storage areas.

Let's see an example of how these work.

[SOUND] From the moment you turn your computer on to the moment you turn it off,

your computer is constantly using memory.

When you turn on your [SOUND] computer and it loads the operating system,

it's usually loading this from the hard drive to the system's RAM.

This allows the central processing unit, or CPU, to [SOUND] have immediate access

to the operating system, which enhances the overall performance and functionality.

Similarity, when you open an application, it's loaded into RAM.

In order to conserve RAM usage,

many [SOUND] applications load only the essential parts of the program at first.

It will only load other [SOUND] pieces when you ask for them.

Say you click on the Word application on your computer.

Your [SOUND] operating system receives that request and Word is loaded into RAM.

[SOUND] Then you want to open up a story you're writing.

When you click on your story document, that file's then loaded into RAM.

After reading for awhile, you make some changes and then [SOUND] save your work.

When you save, the edited [SOUND] file is written to the specified storage device.

[SOUND] If you don't save your work,

it won't transfer the data to a more permanent storage area.

And it will be lost if you suddenly [SOUND] quit the application or

it crashes.

When you exit Word, [SOUND] the application and any

documents are purged from RAM in order to make room for new applications and data.

[SOUND] This repeated quick-loading and

emptying is why is RAM is a temporary storage area.

[SOUND] I'm always curious about what these things actually look like, so

let's check out the teardown on ifixit.com.

I'm going to be using the Macbook Pro teardown to show you

what computers look like, but it's always good to look at the device you're using.

When you get a chance, search for the teardown of your own device.

If you get the chance to deconstruct a computer at home,

remember to disconnect your device from any power supply.

And disconnect and remove the battery as soon as you can get to it.

Okay.

Now that I'm finished with my PSA,

let's check out the teardown of my computer a MacBook Pro.

Right after they disconnect the battery, the first thing they remove is the RAM.

Remember this is the fast temporary storage nearly all data goes through.

Next they remove the hard drive.

Let's jump over to a teardown of the hard drive so we can see inside.

Here we can see there's a large disk or

a few large disks called platters and a read-write arm.

Hard drives store memory using magnetism.

Each large disk in a hard drive is divided into billions of

tiny areas that can each be independently magnetized or

demagnetized to store either a one or a zero.

Magnetism is used in computer storage because each of these tiny

areas remain magnetized or demagnetized even when the power is switched off,

permanently storing the data.

The reason why we don’t use this kind of storage all the time is because it’s

relatively slow compared to RAM.

And if you always had to load programs directly from your hard drive,

the overall performance of your computer would be terribly slow.

[SOUND] Hopefully, this gives you a good understanding of data and

where it's stored in the computer.

In the next stage, we'll leave hardware behind and

talk about software and programming.

To do this, we'll explore the fundamentals of computer software,

learn about a few programming languages, and figure out how they work together.