The computer, demystified.  Comparing the computer to an office.

Matthew ClarkWeb Applications Developer
Many people don't really know what the difference is between memory and storage. And most regular users don't understand the relationship between any of those fancy words printed on the front of their new computer. Of course, it's perfectly fine -- we are all experts at something, and we can't be experts at everything. Well, friends, I would like to share with you an easy-to-follow analogy that will make you grin from ear-to-ear. I guarantee you'll understand how a computer works after reading this article.

That big, square metal box is an office

If you were to take the cover off your PC, what would you see inside? A mass of wires and blinking things, perhaps? That's probably what many people might expect. Actually, imagine that metal case as an office. Inside are all the tools a worker needs to do their job. Now, that office is fairly worthless without you in it, right? Why? Because you are the one who's doing the work! Stick with me.

In your office, you have a desk where you do your work. You probably have a filing cabinet where you keep all of that work and information. You likely have various other things, too because they make your job just a little more pleasurable.

Inside your PC are parts whose terms you may have already heard of: RAM, or memory; hard drive; network card; and various other components. These components, like the things in your office, are the tools inside your computer's "office".  However, we'll only discuss the necessary items in this article.

The processor is the worker

When you are in your office, who is it that does the real work? Is it your stapler? No. Does work get done all by itself inside the filing cabinet? Poppycock! Work gets done because you get it done! You sit at your desk and you work at each task until they are complete. Everything else in your office is there to assist you. Some of those things you need, like your desk and your filing cabinet, and others are just handy, like your radio and your phone. But without you, nothing gets done.

Same goes for your computer; without the processor, nothing gets done. All of the other components are worthless without the processor doing its job. But the processor needs some of those other components to help get the job done. A few of those components are necessary, like memory and hard drive, while the others are just helpful, like the network card and sound card.  

There are two classes of processors out there these days: 32-bit and 64-bit. Actually, they have both been around for a long time, but the 64-bit was reserved for number crunchers in scientific arenas. Up until the last few years, all home computers were 32-bit. But what the heck is the difference?

Well, in our analogy, you are the processor - a 32-bit processor, actually. But if you were a 64-bit processor, you would be able to do more work at the same time without having to look back at your papers. In other words, 64-bit processors can crunch twice as much data in one cycle than a 32-bit processor (we'll talk more about cycles later on). In today's world of video-editing and game-playing, the technology that was reserved for scientific use is now becoming a necessity.

The RAM is a desk

When you enter your office, you sit at your desk, right? And at the beginning of the day, your desk is clean -- you haven't started work yet. Where do you work on things? Do you work on them in the floor? Do you work straight out of your filing cabinet? No, you work on things at your desk because it holds all of your work in front of you; it's the most efficient place to do your work.

If you have a small desk, it's hard to work on some projects if they are rather large. Small projects are no big deal, though, like reading a letter or using your calculator. But you don't work on just one thing at a time -- you are a multi-tasker; you can do many things at once. But if your desk is too small, it's more of a struggle to be productive. So what do you do? You get a bigger desk! Wow, now you can really spread out and breathe!

Your processor works the same way as you do. But instead of a desk, it has memory. Memory is referred to as RAM, or random access memory.  RAM is a series of memory chips and it's where the processor keeps its active tasks. Unlike the hard drive, which we cover later, RAM requires power to hold data -- kind of like how you need the lights on to see your desk. When the power goes out, anything in RAM gets lost forever. Same with your desk -- if your light goes out, you can't see to work and you've lost everything. Well, not really, I suppose - this is where my analogy has a hole, but you get my point.

How do you do your work? Well, remember, your desk is clean at the start of the day because you haven't yet begun your work. To begin, you go to your filing cabinet and pull out some things to work on and you bring them to your desk. You don't work out of your filing cabinet -- that makes no sense! Work would be too slow. Each task has its own little place on your desk so you can see it all and access whatever task you want to work on at any time. And, as we said, the larger the desk, the more things you can have out and open to work on.

When you finish with a particular task, you simply toss it back into the filing cabinet. Because you're so busy, you don't have time to put it back in the same order it was in, nor even in the same drawer for that matter! Yeah, it sounds sloppy, but at least the work was done and you've stored it safely in your filing cabinet. And yes, this habit will come back to bite you later, but we can deal with it then&

Oh, you'll remember that I said if you're desk is too small, it's harder to do your work. I also said that the solution is to get a bigger desk, right? Well, okay, but if you get a bigger desk, it'll take three weeks for it to be delivered. Meanwhile, you still have to "make do" with what you've got. And what do you do when you can't fit all of your work on your desk? You take the pile that you've paid the least amount of attention to and you stack it up on top of your filing cabinet. It's still out for processing because you didn't put it in the filing cabinet - it's just out of your way to make more room on your desk for more important things.

That's right - you use the top of your filing cabinet as if it were your desk. You can still see the work, but it takes a little extra effort (and therefore extra time) to keep going back and forth to it, which is why you only move tasks with the least amount of attention up there. Well, in a computer, this is called "virtual memory", "pagefile", or "swapfile". In a computer, virtual memory is literally a file on your hard drive that is used as if it were RAM.

When your computer is doing more things than will all fit into RAM, it starts using a chunk of your hard drive. This is not a problem, but it needs to be addressed because it can negatively impact performance. Just imagine having to roll your chair over to your filing cabinet and stand up just to look at that particular file, and then going back to your desk!

The hard drive is the filing cabinet

The hard drive is where all files are stored. Every program, every picture, every song, and every document you create -- it's stored on the hard drive and nowhere else. Just like in your office, you keep your work, how-to binders, and other items in your filing cabinet. The only times you access your filing cabinet are when you need to open something new or when you need to save something you've worked on. You might also keep things in your desk drawers, but for this analogy, they're the same thing as your filing cabinet. The point is that you don't keep your things on your desk surface for safe-keeping.

Just a moment ago, I told you that when you get your work done, you just toss it into the filing cabinet in a rather random manner. Well, of course this isn't true, but this is how the hard drive works. As it stores files, it simply places them wherever there's an open spot. This is safe, of course, and it's just how the thing works. Now, do you also remember how I said this would come back to bite you later? It's now time to define and clarify that.

Imagine actually working this way in your office - just tossing your files into the filing cabinet without even looking. What would happen? Things would get out of order and it would take longer to find your files. Well, after a computer has been used for a while, this is exactly what happens - all the files get jumbled up and it takes longer to launch programs and open files. But there is a solution!

If you just got to a point where you couldn't work well enough due to the confusion that is now your filing cabinet, you might hire a starving college student to come in and re-organize it. He would go through each drawer and move anything that was necessary to get your files into an order that was easier for you to work with. Well, that kid's name is Disk Defragmenter! Yes, this tool is built-in to Windows and is guaranteed to speed up your work flow.

Oh, and by the way, on some of the things you were working on, you used post-it notes to help you along the way. Well, those are temporary files and they can be thrown away when you are done. But they take up space on your filing cabinet, and if your starving college kid has to sort through junk, it makes his job take longer. Well, your computer's hard drive can accumulate garbage like this, so you can use another tool, called Disk Cleanup, to find all that junk and remove it.

So let's review

Your office is the computer. Inside your office is your desk (RAM), your filing cabinet (hard drive), and you (the processor). These things are worthless without you there to use them, but you aren't able to do your job without them. Everything else in your office isn't absolutely necessary and is just there to help out.

"But I still have questions." Well, this article wasn't supposed to be the end-all technical explanation. It was merely an aid for you to understand what the main components of a computer are and how they work together. But I will share some extra details to help integrate what you might already know with what I've shared here. If you want to stop reading now, you may! But for those of you who are really following this, but would like to know what megahertz and gigabytes are, read on!

More about processors

The speed of a processor is measured in megahertz (MHz) or gigahertz (GHz). One hertz is equal to cycle in one second (a cycle being an on or off action), and it takes one million hertz to make a megahertz and one billion hertz to equal a gigahertz. So this means your 2 gigahertz processor is equivalent to 2,000 megahertz, which is 2 billion operations in a single second!

As of this writing, typical processor speeds are in the neighborhood of about 2 - 3GHz. These speeds have been in this range for a few years now, but if you were paying attention before that, it seemed like processor speeds were doubling every other week. Well, it turns out we just can't make silicon and metal work any faster without serious heat and stability issues - it's a physics thing.

Well now, processors are being manufactured in multi-core designs. The core of a processor is called, well, a core. We can't make one core go any faster, so we'll put more cores on the same chip. This is like you having a twin brother or sister sitting with you behind your desk - you each get a chunk of the work and you both get it all done faster, even though each of you is still the same speed. So a multi-core processor is actually two processors on the same chip.

Other factors that can help are things like cache memory. You can think of cache like your short-term memory. It's built in to the processor, like short-term memory is built into your head. The more short-term memory you have, the more efficient you can work (keeping track of numbers and things in your head). Same goes for the processor - more cache means higher efficiency when working with large tasks.

There is also the front-side bus speed. "Oh, geeze, a new term, and it's huge!" Please accept my apologies, but it's a simple thing to describe now that you know everything else! The front-side bus, or FSB, is simply the interface between the processor and the rest of the computer. The FSB is usually slower than the processor itself. Like you: you're probably pretty quick in your head. But when you write things on paper or flip through file folders, your hands and arms are a little slower than your mind wants to be.

Well, the FSB is also measured in MHz, but it's usually a smaller number than the processor speed itself. But, of course, the higher the FSB speed, the faster the processor can interact with the other things in its "office".

More about RAM

There are many types of RAM, but they all work off the same concept: as long as they have power, they can store things very quickly, and recall them just as quick. RAM is measured primarily by how much it can hold, and today, the unit of measure is gigabytes.

It's also measured by its speed, like a processor, but that isn't the most important factor. We won't worry about what a byte is, other than it's a unit of measure for any amount of data. As before, mega is one million, and giga is one billion. However, memory is measured in base two instead of base ten, so one million is actually 1,048,576 bytes, not 1,000,000.

Yeah, I know, it's confusing. But not to worry! All you need to know is that acceptable memory sizes these days are at least two gigabytes all the way to as much as you can afford (almost).  And when you hear a geek talking about his machine and he says "Yeah, I've got two gigs of RAM", he's just speaking in slang for two gigabytes, or 2GB.

There is a 4GB limit, though, unless you buy a computer with a 64-bit processor (then the limit is 128GB). Why? Believe me, you don't want to cover that here - way too geeky!

More about hard drives

Hard drives, like RAM, is also measured by the amount of data is can hold, but its unit these days is strictly in gigabytes. Actually, we've already got terabyte hard drives on store shelves - that's a trillion bytes! And if your head didn't pop just now, this will do it: one trillion bytes can be expressed like this: 1,099,511,627,776 bytes. Oh, and one byte is eight bits (a bit is a "0" or a "1"), so a 1 terabyte hard drive can hold 8,796,093,020,000 ones and zeros!  Boy, if I had a nickel for every...

Anyway, there are two other factors that are slightly important: cache (or buffer) size and spindle speed. But before I can define those, I have to describe how a hard drive works.

Inside a hard drive is a set of disks, called platters. The platters rotate on a spindle, which is driven by a precision electric motor. The motor spins the platters, and a "head" glides across the surface of the platters. This head is consists of elements and sensors and are what actually writes the zeros and ones into the metallic coating of the individual platters.

This means the hard drive is a mechanical device. Since it's mechanical, it's slower than all other components in the computer. Do you ever lose your train of thought while working because you had to stop and open the filing cabinet? Well, that's kind of the same thing with hard drives. So, they have a cache that gives data a place to sit before being stored. You can think of hard drive cache as a little stool or table next to your filing cabinet.  The larger the cache, the less likely your computer has to stop and wait for the hard drive to store your data. A good hard drive will have a 16 to 32 MB cache (or greater, if such a size exists).

What about everything else?

Oh, right, the monitor, mouse, keyboard, printer... I didn't forget about all of those.  Actually, those aren't necessary for the computer to do it's job, but actually, for you to tell the computer what to do and see it's progress or result.  Aside from that, I'm sure you already know about those things.  But, just for humors' sake, let's take just a moment to get into that.

You could compare a keyboard and mouse to the boss standing outside the office, shouting directions to the worker.  And on a humorous note, you could compare the monitor to the worker pressing his finished papers against the window for the boss to see.  Hah!  Thank goodness real office life doesn't work that way, eh?

The real conclusion

So, we've taken an easily-identifiable office environment and compared each major component with the mysterious components of a computer. Here and there, we've launched off into a tangent, but I hope those weren't too deep as to detract from the point of my article. Now the next time you're shopping for a computer, or having to deal with a computer repairman (or nerdy friend), you'll fit right in!
Matthew ClarkWeb Applications Developer

Comments (4)

b0lsc0ttIT Manager

Good article!  I have always liked the analogy you used and find it works great to explain the computer parts you mentioned.  It was a pleasure to read and nicely informative.  You promised the reader would "understand how a computer works" and I feel you did a good job of it.  Now that mysterious machine should be a little less confusing. :)

Absolutely a wonderful read.  I'm a geek, so I was curious as to how well you would be able to translate our speak into people speak.  I think you did a wonderful job.

Now what about:

The computer, demystified.  Comparing the computer to a (restaurant/factory/backhoe).  :)

I look forward to your next article.
BillDLGeneral Factotum

I love this sort of analogy.  I try to use this type of description myself in answering questions asked by people clearly not acquainted with certain aspects of hardware, software, etc, but your explanations are excellent.  That is exactly how computing courses should begin.

Your article now makes it clear to me "Why a faulty computer is like a government department".

Thumbs up from me too.....I use the same filing cabinet/desk analogy to explain what RAM and hard drive space is. Great job!

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