( 
)What kind of computer to I need to send email? What do all these numbers mean? What is the difference between RAM and a hard drive? Over the years I've been working with computers, it seems new users always have the same questions, but unfortunately they don't always get an easy answer. For some, the whole concept of computer terminology and operation is simply too foreign. Many times, their questions are only answered with more technical responses! This often leads to confusion and frustration.
After you read this short guide, I hope you'll be a bit more knowledgable on how to decode "computer talk", as well as actually understanding some basic computing concepts! The very basic operation of a computer will be presented using a very familiar analogy.
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After you read this short guide, I hope you'll be a bit more knowledgable on how to decode "computer talk", as well as actually understanding some basic computing concepts! The very basic operation of a computer will be presented using a very familiar analogy.
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First, meet Sally!
Sally the Schoolgirl is going to be our willing assistant in learning about our computer system. She's a fast learner, but don't worry...she won't leave you behind!First thing's first -- What is a CPU? (Central Processing Unit)
Often, you may hear the CPU referred to as the "brain" of the computer. In fact, it's exactly that! The CPU is what "thinks" or "processes" information, controls other functions of the computer, and (hopefully!) gives you the results you were wanting.
CPU speeds today are commonly referenced by their frequency, or how many times they "operate" per second. Usually, this number will be in the billions! Today's modern CPU speeds can reach speeds in excess of three billion (giga, or "G") "operations" per second! Theses "operations per second" have a scientific definition, called "hertz", abbreviated "hz"
So, if a computer has a 3.0Ghz CPU, that translates into "Three billion operations per second!" Easy, huh?
CPU speeds today are commonly referenced by their frequency, or how many times they "operate" per second. Usually, this number will be in the billions! Today's modern CPU speeds can reach speeds in excess of three billion (giga, or "G") "operations" per second! Theses "operations per second" have a scientific definition, called "hertz", abbreviated "hz"
So, if a computer has a 3.0Ghz CPU, that translates into "Three billion operations per second!" Easy, huh?
So, a CPU (Central Processing Unit) with a higher Ghz number is faster, right?
Well, sorta. If you stay within the same CPU "family", then generally speaking the higher frequency is faster, but comparisons of differing CPUs cannot normally be made using CPU speeds. Huh?
Let's use Sally the Schoolgirl in our first example.
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Sally has been assigned some homework. Tonight, she must solve 100 very simple math problems. Sally, depending on how her brain (CPU) has been taught (manufactured), might complete the homework using two very different methods.
1) Sally begins her homework. She solves each problem individually (like most humans do). Because Sally is focusing all her attention on one math problem at a time, she can do them very quickly. Whenever she moves to the next problem, she has completed one operation. She finishes her homework in an hour.
Let's use Sally the Schoolgirl in our first example.
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Sally has been assigned some homework. Tonight, she must solve 100 very simple math problems. Sally, depending on how her brain (CPU) has been taught (manufactured), might complete the homework using two very different methods.
1) Sally begins her homework. She solves each problem individually (like most humans do). Because Sally is focusing all her attention on one math problem at a time, she can do them very quickly. Whenever she moves to the next problem, she has completed one operation. She finishes her homework in an hour.
2) Sally begins her homework. This time, however, she decides to work on two math problems at once! Using this method, Sally has to slow down a little bit. As in the above example, whenever Sally moves to the next problem (or in this case, the next TWO problems), she has completed one operation. Using this method still takes her one hour, because even though her "operations per second (hz)" is slower, she does the same amount of work in an hour.
A real-world example would be to compare two different brands of CPUs.
The company Intel makes the Pentium CPU.
The company AMD makes the AMD line of CPUs.
Compare the Pentium 4 2.5Ghz chip and the AMD XP 2500+ (which runs at 1.8Ghz)
Normally, if you were to see the Pentium chip running at "2.5Ghz" and the AMD chip running at only "1.8Ghz", you would naturally assume the Pentium chip to be faster! (AMD the company realized this, which is why they designate their chip with a "model number" of 2500+).
Even though the Pentium looks faster than the AMD chip on paper, in these two examples they're actually of similar speeds! The Pentium "does math" really fast, but only one problem at a time, whereas the AMD chip "does math" a bit slower, but does two problems at once. Therefore, they do the same amount of work in a given time period.
The Hard Drive (or Hard Disk Drive, HDD) is what the computer uses to store lots of information. If the computer is to lose power, the information on the Hard Disk Drive (HDD) is not lost because the information is stored magnetically....the data has been "written" to the hard drive, and the only way to get rid of the data is to "erase" or "overwrite" the data!
Let's look at Sally the Schoolgirl again. So far, we know the CPU would be Sally's brain, but what would her hard drive be? You may compare a hard drive to her school notebook.
Just like a real hard drive, Sally's notebook has a limited amount of space inside! If Sally were to start taking notes, drawing pictures, etc. in her notebook, eventually she would run out of space and would never be able to write. That sounds horrible! Not really, because there are a few ways to get around this.
1) Sally can erase previous notes (or remove pictures, etc), just like you can erase things from a Hard Drive.
2) Sally can overwrite previous notes with new notes (we're pretending this isn't messy!). A hard drive can do the same thing.
3) Sally can buy a new, larger notebook! Of course, she has to go through the trouble of copying all her old notes over (if she wants), but with a much larger notebook she has lots of room left.
While Sally's notebook capacity is measured in pages, Hard Drive capacity is measured in bytes (pronounced "bites"). Typical hard drives can hold around 120 gigabytes (GB) of data, with some larger drives holding up to 500GB of data!
This is a complex question and ever-changing, but you can generally get by with a few simple questions / rules.
1) Are you only going to use the computer for word processing, email, maybe surfing the internet, or simple games (cards, etc)? Then you're not going to use too much memory. A computer with about 512MB of RAM (using Windows XP) would be fine.
2) Are you going to play slightly more complex games (3-D games), open lots of programs at once, or open large, complex programs? Do you plan on doing light video editing? (professional painting programs, CAD programs, etc) You may want to upgrade to at least 1GB (one gigabyte) of memory.
3) Are you planning to play the latest and greatest 3-D video games? Or edit very large digital pictures using complex painting programs (Adobe Photoshop, Corel Photopaint), or edit very large video files? You might think about using 2GB or more of RAM.
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Hopefully by now you're at least a bit more familiar with the insides of a computer! This has been a very basic look into what makes a computer tick. There are still many more areas to explore, so I hope to see you soon in my next guide!
A real-world example would be to compare two different brands of CPUs.
The company Intel makes the Pentium CPU.
The company AMD makes the AMD line of CPUs.
Compare the Pentium 4 2.5Ghz chip and the AMD XP 2500+ (which runs at 1.8Ghz)
Normally, if you were to see the Pentium chip running at "2.5Ghz" and the AMD chip running at only "1.8Ghz", you would naturally assume the Pentium chip to be faster! (AMD the company realized this, which is why they designate their chip with a "model number" of 2500+).
Even though the Pentium looks faster than the AMD chip on paper, in these two examples they're actually of similar speeds! The Pentium "does math" really fast, but only one problem at a time, whereas the AMD chip "does math" a bit slower, but does two problems at once. Therefore, they do the same amount of work in a given time period.
Okay, I think I have that part. Now, what is a Hard Drive?
The Hard Drive (or Hard Disk Drive, HDD) is what the computer uses to store lots of information. If the computer is to lose power, the information on the Hard Disk Drive (HDD) is not lost because the information is stored magnetically....the data has been "written" to the hard drive, and the only way to get rid of the data is to "erase" or "overwrite" the data!
Let's look at Sally the Schoolgirl again. So far, we know the CPU would be Sally's brain, but what would her hard drive be? You may compare a hard drive to her school notebook.
Just like a real hard drive, Sally's notebook has a limited amount of space inside! If Sally were to start taking notes, drawing pictures, etc. in her notebook, eventually she would run out of space and would never be able to write. That sounds horrible! Not really, because there are a few ways to get around this.
1) Sally can erase previous notes (or remove pictures, etc), just like you can erase things from a Hard Drive.
2) Sally can overwrite previous notes with new notes (we're pretending this isn't messy!). A hard drive can do the same thing.
3) Sally can buy a new, larger notebook! Of course, she has to go through the trouble of copying all her old notes over (if she wants), but with a much larger notebook she has lots of room left.
While Sally's notebook capacity is measured in pages, Hard Drive capacity is measured in bytes (pronounced "bites"). Typical hard drives can hold around 120 gigabytes (GB) of data, with some larger drives holding up to 500GB of data!
But how much is enough? How much "stuff" is 120GB? or 500GB?
Here's a good rule of thumb - The more, the better! A typical Windows XP installation (the software that controls the computer) is about 2GB. A modern video game can run anywhere between 2-4GB. Typical "normal" programs run anywhere between 100MB (megabytes, or 0.1GB) to 500MB (0.5GB) or more. Digital video files can get very large (2GB or more), depending on their quality (clarity) and size.
Doesn't sound like a 120GB hard drive would hold much, now would it? Well, the above examples are pretty "extreme" as far as storage. When you start storing things like songs, normal digital pictures, and text files/email, they are typically very small files. A typical song is around 4MB or so, or only 0.004 GB! This means a 120GB hard drive could hold around 30,000 of our example songs! Text files are even smaller!
Doesn't sound like a 120GB hard drive would hold much, now would it? Well, the above examples are pretty "extreme" as far as storage. When you start storing things like songs, normal digital pictures, and text files/email, they are typically very small files. A typical song is around 4MB or so, or only 0.004 GB! This means a 120GB hard drive could hold around 30,000 of our example songs! Text files are even smaller!
Okay, so what's this "Memory" I keep hearing of. I thought my Hard Drive remembered everything?
These two items, Memory and Storage, are often confused among new computer users.
Again, let's look at Sally the Schoolgirl.
Sally stores all of her notes, pictures, etc. in her notebook (Hard drive). Any time Sally wants to refer to anything in her notebook, she has to open the notebook, flip to the right page, and then read what is written.
Memory (or RAM, "random access memory") is different. You can think of memory as Sally's memory! Of course, Sally is a really smart girl, so her memory is going to work a little bit differently than ours. However, Sally goes to sleep she forgets everything in her memory.
For example, let's say Sally wants to play a game of chess. She invites her mom over to play, but of course Sally doesn't remember the rules. Aha, but she has the rules written down in her notebook ( hard drive!).
Sally flips through the pages of her notebook, eventually finding the rules of Chess. Sally reads the rules of the game, remembers those rules, then closes the notebook to the side and begins to play! Sally never looks at her notebook (hard drive) again because she remembers all the rules. It's much faster for her to read the rules and put them to memory, instead of reading the book for every move she and her mother makes.
In the same way, computer memory enables it to "run faster" because the computer is "remembering" what you're working on. In the example of Sally's chess game, what do you think would be quicker?
1) Sally remembers the rules of the game, so she makes a move. Her mother makes a move, and Sally knows the move is legal because she remembers the game.
or
2) Sally doesn't remember the game. She looks up the rules, remembers a little bit of it, then makes her move. Then, her mother makes a move. She can't remember the rules, so again she looks up the rules in her notebook. Sally does this for every move.
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If you're saying the first method would be much quicker, then you're right! Just as in Sally's example, computers are able to work with data stored in RAM (or memory) MUCH quicker than data stored on hard drives. Unfortunately, when a computer is turned off, it "forgets" everything in memory, just like Sally forgets the rules of Chess every time she goes to sleep.
Again, let's look at Sally the Schoolgirl.
Sally stores all of her notes, pictures, etc. in her notebook (Hard drive). Any time Sally wants to refer to anything in her notebook, she has to open the notebook, flip to the right page, and then read what is written.
Memory (or RAM, "random access memory") is different. You can think of memory as Sally's memory! Of course, Sally is a really smart girl, so her memory is going to work a little bit differently than ours. However, Sally goes to sleep she forgets everything in her memory.
For example, let's say Sally wants to play a game of chess. She invites her mom over to play, but of course Sally doesn't remember the rules. Aha, but she has the rules written down in her notebook ( hard drive!).
Sally flips through the pages of her notebook, eventually finding the rules of Chess. Sally reads the rules of the game, remembers those rules, then closes the notebook to the side and begins to play! Sally never looks at her notebook (hard drive) again because she remembers all the rules. It's much faster for her to read the rules and put them to memory, instead of reading the book for every move she and her mother makes.
In the same way, computer memory enables it to "run faster" because the computer is "remembering" what you're working on. In the example of Sally's chess game, what do you think would be quicker?
1) Sally remembers the rules of the game, so she makes a move. Her mother makes a move, and Sally knows the move is legal because she remembers the game.
or
2) Sally doesn't remember the game. She looks up the rules, remembers a little bit of it, then makes her move. Then, her mother makes a move. She can't remember the rules, so again she looks up the rules in her notebook. Sally does this for every move.
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If you're saying the first method would be much quicker, then you're right! Just as in Sally's example, computers are able to work with data stored in RAM (or memory) MUCH quicker than data stored on hard drives. Unfortunately, when a computer is turned off, it "forgets" everything in memory, just like Sally forgets the rules of Chess every time she goes to sleep.
So, more memory (RAM) is better?
You better believe it! The more memory your computer has, the more information it can "remember" while you're working. The memory is either used to remember really LARGE programs, or lots of little ones, or anything in between. The more RAM you have, the less you have to access your hard drive, and that's always a good thing.
Let's look at Sally again. She begins to play Chess, because she's committed the rules to memory after reading her notebook.
Sally's mother is taking a long time on her move, though, so Sally decides she's going to play Hopscotch with her best friend.
Sally looks up the rules to Hopscotch from her notebook, then begins to play with her friend.
But wait! Sally's mother has completed her turn. It's Sally's turn now...not a problem! Sally, having lots of memory, still remembers the rules for Chess also! She doesn't have to refer to her notebook again. Instead, she simply recalls the rules and acts appropriately. As long as Sally's memory isn't full, she isn't slowed down by having to look up rules from her notebook.
In the same way, a computer with lots of RAM can work with more simutaneous programs at once, or larger programs (like games) without having to access the much slower hard drive over and over. This effect is very, very important for the speed of a computer. A computer with a fast CPU but a very small amount of RAM might run much slower than a computer with a SLOWER CPU but much greater amount of RAM!
Let's look at Sally again. She begins to play Chess, because she's committed the rules to memory after reading her notebook.
Sally's mother is taking a long time on her move, though, so Sally decides she's going to play Hopscotch with her best friend.
Sally looks up the rules to Hopscotch from her notebook, then begins to play with her friend.
But wait! Sally's mother has completed her turn. It's Sally's turn now...not a problem! Sally, having lots of memory, still remembers the rules for Chess also! She doesn't have to refer to her notebook again. Instead, she simply recalls the rules and acts appropriately. As long as Sally's memory isn't full, she isn't slowed down by having to look up rules from her notebook.
In the same way, a computer with lots of RAM can work with more simutaneous programs at once, or larger programs (like games) without having to access the much slower hard drive over and over. This effect is very, very important for the speed of a computer. A computer with a fast CPU but a very small amount of RAM might run much slower than a computer with a SLOWER CPU but much greater amount of RAM!
How much RAM is enough?
This is a complex question and ever-changing, but you can generally get by with a few simple questions / rules.
1) Are you only going to use the computer for word processing, email, maybe surfing the internet, or simple games (cards, etc)? Then you're not going to use too much memory. A computer with about 512MB of RAM (using Windows XP) would be fine.
2) Are you going to play slightly more complex games (3-D games), open lots of programs at once, or open large, complex programs? Do you plan on doing light video editing? (professional painting programs, CAD programs, etc) You may want to upgrade to at least 1GB (one gigabyte) of memory.
3) Are you planning to play the latest and greatest 3-D video games? Or edit very large digital pictures using complex painting programs (Adobe Photoshop, Corel Photopaint), or edit very large video files? You might think about using 2GB or more of RAM.
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Hopefully by now you're at least a bit more familiar with the insides of a computer! This has been a very basic look into what makes a computer tick. There are still many more areas to explore, so I hope to see you soon in my next guide!
Guide created: 05/11/06 (updated 06/01/08)
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