Lesson 8: Computer Care and Safety

Computers, like any other piece of electronic equipment, need special care and attention in order to perform properly and safely. There are several specialized tasks such as defragmenting, scanning and reformatting that computer experts can do to keep the internal system of a computer working well. However, we'll leave these tasks to the experts for now and concentrate on some daily do's and don'ts that any computer user should know.

A Clean Machine

This may seem like a simple topic, but computers require special cleaning even on the outside. Keeping your system free of dust, dirt and liquids is the first step to computer care. Your system's user guide is the best place to find information on how to clean your outer components; but here are some general tips that you should always remember:

• Never spray your monitor screen (or any other computer component) with glass cleaner. Instead, spray a lint-free cloth lightly with glass cleaner, then clean the screen. Be sure to hold the cloth away from the computer when spraying.
• Computer components should be kept as dust-free as possible.
• Canned air or small computer-specific vacuum cleaners are an excellent way to clean keyboards, computer case vents, or around disk drive openings.
• The rubber ball inside the bottom of a mouse may need occasional cleaning. If the mouse does not perform correctly, check your user guide for cleaning directions.
• Never try to remove the cover on your computer to clean inside. Instead, take it to an authorized service technician for cleaning.
• Keep all liquids and food items away from your computer. Liquids and food crumbs can damage delicate electronic circuits. Also, mixing liquids and electronic components can cause serious electrical shock!
• Wash your hands before using the computer to avoid "sticky keys."
• When in doubt about how to clean your computer system, consult your user manual or technical support.

A Shocking Possibility

It is important to remember that your computer is connected to electricity. If you have an Internet connection, that also means that your computer is connected to a telephone line or cable connection. These are also conductive connections. That means that lightning could be conducted to your computer through any of these connections. For safety reasons, you should never use your computer during a storm.

Many computer users purchase surge protectors to safeguard their system. The user plugs computer components into the surge protector, then plugs the surge protector into the wall. Just like the name implies, surge protectors are designed to protect computers against electrical surges or lightning. However, these devices can fail, so it's best to stay clear of the computer during storms.

Also, as mentioned earlier, electricity and liquids don't mix. Keep water and other liquids away from the computer system. This includes drinks, water guns, fish bowls and cleaning fluids.

Beware of Viruses

Viruses and worms are names for pesky computer-unfriendly programs that can accidentally be downloaded into your system. Some are just a nuisance, but others can crash your system and cause irreparable damage. To avoid these nasty creatures, follow these safety tips:

• Install, use and regularly update virus software
• Never open an e-mail attachment unless you know and trust the person who sent it.
• Do not accept downloads from Internet sites that you don't know and trust.

If you would like to learn more about viruses and antivirus utilities, Check outThe Virus Zoo at CNet for some great information!

Avoid Installation Marathons

Let's say that you were given several new computer games for your birthday. Or maybe your parents just bought you a new system and you want to load all your favorite games. Do you sit down and install all of these programs one right after another? No! It may be tempting, but it's not a good idea. Sometimes, installing a new program can cause conflicts within your system. These conflicts will need to be worked out or else the program will have to be uninstalled so that your system will work correctly. If you install 2 or more programs before you realize there is a problem, it will be very difficult to determine what the problem is and which program caused it. Instead, try installing one program, then use your computer long enough to see how your system responds to the installation before loading the next program.

Safe Computing!

Following these guidelines should help you to take good care of your computer system, so that you can get lots of enjoyment from it. Remember, that if you have any questions about your particular system, you should check your user guide or contact technical support.

Lesson 7: files and folders

Read the following information and complete the worksheet/s to finish the assignment.

Computer hard drives hold an enormous amount of data or information. It is very important that all of the data is well organized. That way it is easy for the computer to find what it is looking for. Knowing how a computer's organization system works will help you to find what you are looking for. Computers use files and folders to organize data.

What is a file?

A file is a collection of data that is stored together. Files can be stored on a hard drive, a floppy disk, or a CD. Everything that a computer does is based on data stored in files. You can do lots of things with files - create them, name them, rename them, save them, or delete them. Certain files can even be looked at, listened to, and run.

In some ways, files are like television shows. All TV shows have 3 things, just like computer files:

• Name
• Location
• Length

Just as you recognize your favorite TV program by its name, you can also recognize a file by its name. File names often consist of 2 parts: name and type. There are many different types of TV shows - comedies, dramas, cartoons, sports shows, game shows, etc. Similarly, computer files come in different types - text files, graphic files, program files, e-mail files, etc. In many computer systems, files are named so that you know what type of file it is just by looking at the abbreviation behind the name. A period is used to separate the name from the type, like this: "name.type". If TV show titles came in 2 parts like computer files, they would give the name of the program, followed by a period, followed by the type of show it is. It might look like this: "Sillykids.toon" or "EmergencyRoom.drama" or "Football.sport"! One important thing that you should know about file types orextensions is that they are always written as abbreviations, usually with 3 letters. For example, a text file is shown as .txt and an executable program file is shown as .exe. You may not always see the extension on a file name, because many PCs offer the option of turning off the extension. Even though you don't see it, the computer still does. On the Macintosh system, however, the practice of naming files with extensions is not always followed; but you can see what kind of file it is by the icon or 'kind' identifier in the directory listings. Common Mac extensions you'll see are .sit (a compressed stuffit file), .hqx (a binhexed encoded file), .pdf (Adobe Acrobat file). Web pages (no matter what system) always use extensions to identify the kind of file - .htm or .html for the web pages, .gif for gif graphics, .jpg for jpg graphics and so on.

Files are stored in certain places within your computer, much like TV programs are shown on certain channels. So, to find a file you must know where it is located, just like you must know on what channel to find your favorite TV show. If you forget what channel a TV show is on, you can either flip through channels until you find the program or you can look in a TV guide to find the information you need quickly. The quickest way to find files on most computers is to use Find. This is a type of search program where you can type in the name of a file and the computer will search and tell you where the file is located. If you use a Windows Operating System, Find is located on your Start Menu. On a Macintosh System, Find! is located under File on the menu bar. (More on Start Menu and menu bar in Lesson 8).

TV Programs, like files, have specific lengths. TV shows may be 30 minutes long, 1 hour long, or several hours long. Files are not measured in time, but in bytes. If you'll remember from Lesson 3: Bits & Bytes, a byte is a measurement of stored data. Larger files may be measured in kilobytes or megabytes. The length of a file tells how much storage space that file is using within the computer.

Folders or Directories

With so many thousands of files stored inside a computer, it is very important to keep them organized. Folders, also known as Directories, keep files organized by grouping them together.

Imagine for a moment that you had a giant toy room filled with toys and you were given the job of organizing all of those toys. You decide to start the job by sorting all of the toys and grouping similar toys together. For example, you put all of your red marbles in a box and all of your blue marbles in another box and all of your clear marbles in a third box. Then, you put all of those boxes into a bigger box and label it "marbles". Then, you might even put the "marbles" box into a bigger box that contains boxes of "super balls" and "tennis balls" and "baseballs". You would name that big box "balls". If you continued to organize toys that way, you would end up with an entire room of boxes with labels that contain similar kinds of toys. Then if you needed to find your plastic brontosaurus, you would know to open the box labeled "toy animals" and go past the "bug box" and the "reptile box" until you find the "dinosaur box" - open it and there is the brontosaurus! In this example, the toys are like files and the boxes are like folders. Your computer is set up to store similar files in specific folders. Then similar folders can be put inside other folders, and so on.

Many times, the computer will automatically store files in certain folders in order to keep itself organized. However, when you create new files, you must decide which folders to put them. You can even create new folders to store your files. For example, let's say that a boy named Adam wants to make a folder of all the fun things he creates on the computer. With an adult's help, Adam creates a folder titled "Adam". Within that folder, he creates 3 new folders titled "stories", "drawings" and "jokes". Then, when Adam writes a story called "Alien Tap Dancing", he stores or saves that file that contains the story in the "stories" folder. On a PC, the file name would be "Alien Tap Dancing.txt" because it is a text file.

The best way to keep up with a file is to know its address. The address basically tells you what drive and folders to look in for a file. For example, the address for Adam's story might look like this on a Macintosh system: "Macintosh HD\Users\Adam\stories\Alien Tap Dancing" (Macintosh HD indicates the hard drive). On a PC, the address might look like this: "C:\\My Documents\Adam\stories\Alien Tap Dancing.txt". In this case, the letter "C" indicates the hard drive, as most PCs assign a letter to each drive in the system. Note, that the file address always includes the drive, folder(s), and file name in exactly that order.

Be A Responsible Computer User

Understanding the relationship between files and folders, and how they are addressed and located within your computer system is a very important part of using a computer. Beginners should make it a priority to learn about this early in their computer education. Never delete, move or rename a file unless you are absolutely sure of what you are doing! A computer relies on many files to keep itself running correctly, so changing or deleting those files can cause major computer malfunctions. When in doubt, ask a parent, teacher or other expert for assistance. The safest way to learn about using files and folders is to ask for help in setting up your own personal folder, then creating new folders and files within it.

Lesson 6: operating systems

read the following information and complete the worksheets to finish the assignment

What is an Operating System?

The most important program on any computer is the Operating System orOS. The OS is a large program made up of many smaller programs that control how the CPU communicates with other hardware components. It also makes computers easier to operate by people who don't understand programming languages. In other words, operating systems make computers user friendly.

Do you remember ROM (Read Only Memory) and RAM (Random Access Memory) from Lesson 2? ROM and RAM are very important to the OS. Part of a computer's operating system is built into ROM. That part contains the most essential programs that the computer needs in order to run correctly. The ROM operating system is also known as the BIOS (Basic Input Output System). You may remember from Lesson 2 that the BIOS is responsible for waking up the computer when you turn it on to remind it of all the parts it has and what they do.

The operating system also contains other programs that are important, but not essential to making the computer run. The part of the operating system that contains these programs is stored on a computer's hard drive and is booted to RAM whenever the computer is turned on. This part of the operating system is known as DOS which stands for Disk-based Operating System.

Types of Operating Systems

Different computer manufacturers use different operating systems. Apple has specific operating systems for its line of Macintosh computers. When IBM released their Personal Computer or PC back in the early 1980's, they did not get a copyright on it, which allowed many other companies to build similar computers that were IBM-compatible; in other words, they used the same operating system as the IBM PC. There are different operating systems available for PCs, but the most common is Windows, which was developed by a company named Microsoft. Windows is similar to the Macintosh operating system, because it also uses a mouse and a GUI (Graphical User Interface) that uses graphics or pictures to help the user navigate within the computer system.

There are several versions of Windows (95, 98, NT, 2000), just as there are several versions of Macintosh operating systems (System 7, System 8). Operating systems are constantly being improved or upgraded as technology advances. When a company thinks that their operating system is now more advanced than the one already on the market, they release their new version for sale. Users can then purchase the new version and upgrade the part of the operating system that is stored on the hard drive. The ROM OS is not affected by the upgrade. Upgrading an operating system can have several advantages, such as simplifying tasks and navigation. However, there can be disadvantages, too. Many Windows 95 users upgraded to Windows 98 and discovered that many of their older programs would no longer run using the new operating system.

The Computer Revolution

The introduction of the Macintosh OS and the later introduction of Windows played a large part in making computers accessible to so many people. The user-friendly interfaces of both operating systems made it easier for people with no computer training to learn to use these amazing machines. Other machines, such as typewriters and payroll calculators quickly became a thing of the past, as computers became so easy to use and so affordable.

Lesson 5: Programs

Programming

In Lesson 3, you learned that all of the information that travels through your computer is stored on bits as either an on or off signal. Using bits and bytes in different combinations to represent a code is known as programming. These codes allow the computer to understand instructions. Computer programmers are people who write these codes to create programs. There are evenprogramming languages that make it easier, so that these people don't have to remember all the bit or byte combinations. Programming allows people and computers to communicate more easily.

Computer Programs

A program is a set of instructions that tells the computer how to perform a specific task. For example, your favorite computer game is a program. In order for your computer to know how to play that game, you (or your parents) must firstinstall the program from the game software - usually a CD. Installing the program means that you are copying the program or instructions that are stored on the CD on to your computer's hard drive. Programs can also be downloaded from the Internet directly to your hard drive.

Many programs (especially games) are very large and would take up lots of memory space on your hard drive. To keep that from happening, these programs are designed to only copy part of the program onto your computer. The rest of the program stays on the software disk. The program cannot be run from your computer unless you have the disk in the disk drive so that RAM can read the rest of the program from it.

Other programs install completely on your hard drive, so that they can be used without running the CD. This is very helpful with programs that are designed to help the user perform a specific task, such as typing a letter or creating a birthday card. Having the program run without the CD, frees up the CD-ROM drive in case you might need to run a clip art CD to add some pizzazz to your creation!

read the following information and complete the worksheet/s to finish the assignment

Types of Programs

There are many different types of programs for the computer. They are grouped according to the tasks that they perform. Here are some very common types of programs and some examples of their uses:

• Word processing - letter writing, essays, writing stories
• Database - address books, mailing lists
• Spreadsheets - storing financial information
• Research - encyclopedias, informational programs
• Entertainment - games, music/video programs
• Education - skill practice games, tutorials, how-to programs
• Desktop Publishing - creating birthday cards, newsletters, etc.

Programs do much of the work for us, when we perform tasks on the computer. The program instructs the computer in a language that it understands. Think of how hard it would be to dictate a story for someone else to type if that other person spoke a foreign language! You could learn that person's language, but that could take years. The easiest way would be to have a translator. Programs are like translators that allow people to work with computers without learning the computer's language.

Lesson 4: Storage

Computer Connections: Lesson 4 - Storage

read the following information and complete the worksheet/s to finish the assignment

The purpose of storage in a computer is to hold data or information and get that data to the CPU as quickly as possible when it is needed. Computers use disks for storage: hard disks that are located inside the computer, and floppy or compact disks that are used externally.

Hard Disks

Your computer uses two types of memory: primary memory which is stored on chips located on the motherboard, and secondary memory that is stored in the hard drive. Primary memory holds all of the essential memory that tells your computer how to be a computer. Secondary memory holds the information that you store in the computer.

Inside the hard disk drive case you will find circular disks that are made from polished steel. On the disks, there are many tracks or cylinders. Within the hard drive, an electronic reading/writing device called the head passes back and forth over the cylinders, reading information from the disk or writing information to it. Hard drives spin at 3600 or more rpm (Revolutions Per Minute) - that means that in one minute, the hard drive spins around over 3600 times!

Today's hard drives can hold a great deal of information - sometimes over 20GB!

How Hard Disks Work

The process of reading and writing to a hard disk is done with electricity and magnetism. The surfaces of this type of disks can be easily magnetized. The electromagnetic head of the disk drive records information to the disk by creating a pattern of magnetized and non-magnetized areas on the disk's surface. Do you remember how the binary code uses on and off commands to represent information? On the disk, magnetized areas are on and non-magnetized areas are off, so that all information is stored in binary code. This is how the electronic head can both write to or read from the disk surface.

It is very important to always keep magnets away from your computer! The magnets can erase information from the hard disk!

Compact Disks

Instead of electromagnetism, CDs use pits (microscopic indentations) andlands (flat surfaces) to store information much the same way hard disks use magnetic and non-magnetic storage. Inside the CD-ROM is a laser that reflects light off of the surface of the disk to an electric eye. The pattern of reflected light (pit) and no reflected light (land) creates a code that represents data.

CDs usually store about 650MB. A DVD or Digital Video Disk holds even more information than a CD, because the DVD can store information on two levels, in smaller pits or sometimes on both sides.

Why Do You Need External Disks?

You might wonder: If all the information is stored safely inside my computer, why would I need to store it outside? There are several reasons why portable storage is so important.

CDs and other kinds of external memory make it possible to backup important information in case it is lost by the computer. Do you remember in Lesson 2, we talked about RAM and ROM? RAM loses its memory each time the computer is turned off, but ROM keeps information stored even when the computer is not turned on. Well, sometimes computers have problems that can cause them tocrash. No, that doesn't mean they jump off the desk and smash on the floor. A crash is something that happens inside the computer's circuits and can make it forget things. Some crashes can even make ROM forget everything! Having important information backed up on disks will allow you to put it back into your computer's memory. Backup disks can save you lots of time and headaches.

Disks also allow information to be transferred between different computers. Let's say that you are working on a project using a computer at the library, but you don't finish it by closing time. There's your project sitting in the computer. How do you get it home to finish it on your computer? You write the information to a disk, take it home and upload the information into your computer from the disk. What an easy way to transfer information!

Uses of Compact Discs

The most common use for compact discs (aside from playing music) is storage of software programs. When you purchase a computer game, the program that tells your computer how to run the game is stored on a CD. You move the program into your computer's memory by installing it. Some programs are transferred completely into your computer's hard drive. However, many programs are very large and would take up lots of memory space on your hard drive. To keep that from happening, these programs are designed to only upload part of the program onto your computer. The rest of the program stays on the software disk. The program cannot be run from your computer unless you have the CD in the disc drive so that RAM can read the rest of the program from it.

With the introduction of CD-RW (disc drives that can write to compact discs as well as read from them), CDs can now be used for storage. Using a CD-RW, computer data can be backed up to a CD. All kinds of information can now be saved on CD. Many people store music files or family photos on CD.

Lesson3: Bits and Bytes

Computer Connections: Lesson 3 - Bits & Bytes

read the following information and complete the worksheet/s to finish this assignment.

Did you know that all of the information that travels through your computer is based on two commands? It's true. The only data that a computer can understand is on and off. But, the millions of combinations of those two commands given in series are what make a computer work.

Binary Code

Remember the power supply that is inside your computer and how it sends electricity to all of the components? That electricity is what creates an on signal. The memory chips inside your computer are divided into thousands of tiny compartments called bits. Each bit has an electronic switch or gate. On means the gate is open and letting electricity go through. The computer reads on or openswitches as a number 1. Closed gates are off because the electricity is blocked and cannot get through. The computer reads off bits as 0. It is by grouping these bits together to form a series of 1/0commands, that data is formed. Eight bits are grouped together to form abyte. In this group of eight, there are 256 possible combinations of 1/0. The grouping of 1/0 within a byte is called Binary Code.

Here's an example of the Binary Code in action: When you type the letter A on your keyboard, electrical signals are sent from the keyboard to the CPU. The CPU turns the signals into binary code. Then, the computer reads the code and sends it on to the monitor to display the letter A.

KB, MB & GB

You may have seen these abbreviations many times before. Do you know what they mean?

• KB = kilobyte = about 1,000 (one thousand) bytes, (1024 or 2^10)
• MB = megabyte = about 1,000,000 (one million) bytes, (1,048,576 or 2^20)
• GB= gigabyte = about 1,000,000,000 (one billion) bytes (1,073,741,824 or 2^30)

As you can see, these abbreviations stand for a specific number of bytes. And each byte holds 8 bits capable of forming 256 combinations of 1/0. Wow!

The number that comes before one of these abbreviations represents the computer's memory capacity. For example, if a computer has 64MB of RAM that means that the computer can handle 64,000,000 (64 million) bytes of random access memory (that's 64,000,000 microscopic 8-bit panels). Hard disk space is also measured in bytes. So, a 15GB hard drive has 15,000,000,000 (15 billion) bytes for storing memory.

Look at your keyboard. Each character key is represented by a number that is held in a single byte. Remember how the letter A is sent to the CPU to be translated into binary code? The numerical value of the uppercase letter A is 65. That number 65 is represented in one byte - a combination of 1 and 0 oron and off switches. The computer cannot understand letters, so it translates them into numbers that are represented by patterns of on and off. To get an idea of how much on/off data a computer can store, just imagine pressing one key one billion times! How long would it take? If you pressed the key 5 times per second, it would take you over 6 years of continuously typing to reach 1 billion keystrokes equal to 1GB of memory! And many computers today can store over 20GB of memory on their hard disks! Incredible! So, the next time your computer is taking a long time to load a web page, think of how fast it really is going!

LESSON 2: hardware on the inside

Computer Lesson 2: Hardware on the inside

Read the following information and fill out the worksheet/s to complete the assignment.

Computers are made of many electronic components or parts. These components each have a special job and they all work together to make your computer operate. Some components are hidden inside the computer where you can't see them. Others can be seen partly from the outside.

Power It Up!

Every computer needs a power supply to take electricity from your house and convert it into a current that works for your computer. The electrical cord that comes out of your computer comes out of the power supply. When it is plugged into the wall, electricity travels from the electrical wires in your house into the computer's power supply. When your computer is turned on, the power supply allows the converted electricity to travel to other components inside the computer.

Circuits

The motherboard gets its name because it is like a mother to all of the other circuit boards. Found at the bottom of a desktop case or the side of a tower case, the motherboard is the largest circuit board and has many smaller boards plugged into it. It holds all of the most important parts of the computer.

On the motherboard, you will find severalexpansion cards. Each of these cards has a special purpose. The sound card contains special circuits for operating the computer's sound. Thevideo card handles graphics that are displayed on the monitor. There are also expansion cards for other computer components including the drives and ports.

The modem is an expansion card that allows computers to talk to each other. A modem plugs the computer in to a phone or cable line so that information can be transferred between computers. Current modems can run up to 56,000 bits per second. Don't know what a bit is? Don't worry, we'll get to that in a later lesson

The brain of a computer is the CPU orCentral Processing Unit. Like a brain, it controls information and tells other parts what to do. The type of CPU in a computer also determines how fast that computer can operate. A CPU generates lots of heat, so there is usually a small fan nearby to cool it down.

A very important computer component is the BIOS chip. BIOS stands for Basic Input Output System. In very simple terms, the BIOS chip wakes up the computer when you turn it on and reminds it what parts it has and what they do.

RAM & ROM

Have you ever heard the terms RAMand ROM? These two terms sound very similar and can easily be confused by beginners. However, understanding what they mean and what they do can help you to remember.

RAM stands for Random Access Memory. RAM chips will remember what you tell them and can even change to remember new information. But, when the computer is turned off, RAM forgets everything you told it. This is why it is so important to save your work on a computer - if the computer gets turned off, RAM will lose all of your work!

ROM stands for Read Only Memory. ROM is good at remembering, but cannot change it's mind. It holds information that is built into it. ROM is like reading a library book - lots of information is there, but you can't change it (because you never write in a library book). RAM, on the other hand, is more like a journal - you can write information into the journal. But if you change your mind, you can erase and write in new information.

Ports

Ports are the places on the outside of the computer case where you plug in hardware. On the inside of the case, they are connected to expansion cards. The keyboard, mouse, monitor, and printer all plug into ports. There are also extra ports to plug in extra hardware like joysticks, gamepads, scanners, digital cameras and the like. The ports are controlled by their expansion cards which are plugged into the motherboard and are connected to other components by cables - long, flat bands that contain electrical wiring.

Disk Drives

Disk drives read information off of storage disks. The three most common disk drives are the hard drive, floppy disk drive and CD-ROM. In lesson 1, you learned a bit about the latter two, which are usually installed inside the front of your computer case so that you can get to them from the outside to load the software. The hard drive, however is hidden inside the computer because the disks are not meant to be removed. Information that you save on your computer is stored on these hard disks. You can learn more about storage disks in Lesson 4: Storage; but first, check out Lesson 3 to learn about bits and bytes.