Introduction To Computer MCQ's

A computer is an electronic device that manipulates information, or "data." It has the ability to store, retrieve, and process data. You can use a computer to type documents, send email, and browse the internet. You can also use it to handle spreadsheets, accounting, database management, presentations, games, and more.

Personal Computer

OR



A programmable machine. The two principal characteristics of a computer are:

• It responds to a specific set of instructions in a well-defined manner.
• It can execute a prerecorded list of instructions (a program).

The first electronic computer, the Electronic Numerical Integrator and Computer (ENIAC), was developed in 1946. It took up 1,800 square feet and weighed 30 tons.

All types of computers consist of two basic parts:

1.        Hardware

2.       Software

1.    Hardware

Hardware is any part of your computer that has a physical structure, such as the computer monitor or keyboard.

Hardware Device
Peripheral device(Input/output)	Input	Mouse, Keyboard, Joystick, Image scanner, Webcam, Graphics tablet, Microphone,
	Output	Monitor, Printer, Loudspeaker
	Both	Floppy disk drive, Hard disk drive, Touch Screen Monitor, Optical disc drive, Tele printer
Computer busses	Short range	RS-232, SCSI, PCI, USB
	Long range (Computer networking)	Ethernet, ATM, FDDI

                                    

2. Software 

Software is any set of instructions that tells the hardware what to do. It is what guides the hardware and tells it how to accomplish each task. Some examples of software are web browsers, games, and word processors such as Microsoft Word.

Computer Monitors

      The computer monitor is an output device that is part of your computer's display system. A cable connects the monitor to a video adapter (video card) that is installed in an expansion slot on your computer’s motherboard. This system converts signals into text and pictures and displays them on a TV-like screen (the monitor).

The computer sends a signal to the video adapter, telling it what character, image or graphic to display. The video adapter converts that signal to a set of instructions that tell the display device (monitor) how to draw the image on the screen.

Cathode Ray Tube (CRT)
The CRT, or Cathode Ray Tube, is the "picture tube" of your monitor. Although it is a large vacuum tube, it's shaped more like a bottle. The tube tapers near the back where there's a negatively charged cathode, or "electron gun". The electron gun shoots electrons at the back of the positvely charged screen, which is coated with a phosphorous chemical. This excites the phosphors causing them to glow as individual dots called pixels (picture elements). The image you see on the monitor's screen is made up of thousands of tiny dots (pixels). If you've ever seen a child's LiteBrite toy, then you have a good idea of the concept. The distance between the pixels has a lot to do with the quality of the image. If the distance between pixels on a monitor screen is too great, the picture will appear "fuzzy", or grainy. The closer together the pixels are, the sharper the image on screen. The distance between pixels on a computer monitor screen is called its dot pitch and is measured in millimeters. (see sidebar). You should try to get a monitor with a dot pitch of .28 mm or less.

Note: From an environmental point of view, the monitor is the most difficult computer peripheral to dispose of because of the lead it contains.

There are a couple of electromagnets (yokes) around the collar of the tube that actually bend the beam of electrons. The beam scans (is bent) across the monitor from left to right and top to bottom to create, or draw the image, line by line. The number of times in one second that the electron gun redraws the entire image is called the refresh rate and is measured in Hertz (Hz).
If the scanning beam hits each and every line of pixels, in succession, on each pass, then the monitor is known as a non-interlaced monitor. A non-interlaced monitor is preferred over an interlaced monitor. The electron beam on an interlaced monitor scans the odd numbered lines on one pass, then scans the even lines on the second pass. This results in an almost imperceivable flicker that can cause eye-strain.

This type of eye-strain can result in blurred vision, sore eyes, headaches and even nausea. Don't buy an interlaced monitor, they can be a real pain in the ... ask your optometrist.

Interlaced computer monitors are getting harder to find (good!), but they are still out there, so keep that in mind when purchasing a monitor and watch out for that "steal of a deal".

Video Technologies
      Video technologies differ in many different ways. However, the major 2 differences are resolution and the number of colors it can produce at those resolutions.

Resolution
      Resolution is the number of pixels that are used to draw an image on the screen. If you could count the pixels in one horizontal row across the top of the screen, and the number of pixels in one vertical column down the side, that would properly describe the resolution that the monitor is displaying. It’s given as two numbers. If there were 800 pixels across and 600 pixels down the side, then the resolution would be 800 X 600. Multiply 800 times 600 and you’ll get the number of pixels used to draw the image (480,000 pixels in this example). A monitor must be matched with the video card in the system. The monitor has to be capable of displaying the resolutions and colors that the adapter can produce. It works the other way around too. If your monitor is capable of displaying a resolution of 1,024 X 768 but your adapter can only produce 640 X 480, then that’s all you’re going to get. 
      When we talk about the different technologies, we’re talking about the video card and monitor that make up that display system. Also, standards describe the basic number of colors and resolutions for each technology, but individual manufacturers always take liberties, providing options and enhancements that are designed to make their product more appealing to the end user. This is, of course, how new standards come about.

Monochrome
      Monochrome monitors are very basic displays that produce only one color. The basic text mode in DOS is 80 characters across and 25 down. When graphics were first introduced, they were fairly rough by todays standards, and you had to manually type in a command to change from text mode to graphics mode. A company called Hercules Graphics developed a video adapter that could do this for you. Not only could it change from text to graphics, but it could do it on the fly whenever the application required it. Today’s adapters still basically use the same methods.

CGA/EGA
      The Color Graphics Adapter (CGA) introduced color to the personal computer. In APA mode it can produce a resolution of 320 X 200 and has a palette of 16 colors but can only display 4 at a time. With the introduction of the IBM Enhanced Graphics Adapter (EGA), the proper monitor was capable of a resolution of 640 X 350 pixels and could display 16 colors from a palette of 64.

VGA
      Up until VGA, colors were produced digitally. Each electron beam could be either on or off. There were three electron guns, one for each color, red, green and blue (RGB). This combination could produce 8 colors. By cutting the intensity of the beam in half, you could get 8 more colors for a total of 16. IBM came up with the idea of developing an analog display system that could produce 64 different levels of intensity. Their new Video Graphics Array adapter was capable of a resolution of 640 X 480 pixels and could display up to 256 colors from a palette of over 260,000. This technology soon became the standard for almost every video card and monitor being developed.

SVGA

      Once again, manufacturers began to develop video adapters that added features and enhancements to the VGA standard. Super-VGA is based on VGA standards and describes display systems with several different resolutions and a varied numberof colors. When SVGA first came out it could be defined as having capabilities of 800 X 600 with 256 colors or 1024 X 768 with 16 colors. However, these cards and monitors are now capable of resolutions up to 1280 X 1024 with a palette of more than 16 million colors. 

XGA
      Extended Graphics Array was developed by IBM. It improved upon the VGA standard (also developed by IBM) but was a proprietary adapter for use in Micro Channel Architecture expansion slots. It had its own coprocessor and bus-mastering ability, which means that it had the ability to execute instructions independent of the CPU. It was also a 32-bit adapter capable of increased data transfer speeds. XGA allowed for better performance, could provide higher resolution and more colors than the VGA and SVGA cards at the time. However, it was only available for IBM machines. Many of these features were later incorporated by other video card manufacturers.

Review:-

1. Environmentally, which is the most difficult to dispose of?
a) hard drives
b) monitors
c) power supplies
d) motherboards


2. What should you use to clean the plastic cover on your monitor or PC? Choose all that apply.
a) alcohol
b) lint free cloth
c) WD-40
d) mild soap solution


3. Your monitor has a cable or cord that connects the monitor to a/an _________ that is installed in an expansion slot on the computer's motherboard.
a) CPU
b) video adapter
c) VGA connector
d) RJ-45 connector


4. The CRT is the picture tube of your monitor. CRT is an acronym for ____________.
a)  Cathode Ray Tube
b)  Cathode Radio Transmitter
c) Video Picture Tube
d) Calcidium Ray Transceiver


5. The individual dots that make up the actual picture on your computer's monitor are known as picture elements or pixels.
a)  True
b)  False


6. The number of pixels across the top of your screen times the number of pixels down the side will give you the total number of pixels used to draw the image. This is known as the monitor's ___________.
a)  dot pitch
b)  resolution
c) refresh rate
d) aperature


7. The Graphical User Interface or GUI (gooey) is one of the least popular computer interfaces.
a)  True
b)  False


8. The closer pixels are to each other, the sharper the image will appear. The distance between pixels on a monitor is called it's __________ .
a) refresh rate
b) dot pitch
c) pixelation
d) resolution factor


9. IBM developed the first analog display adapter called the _________.
a) XGA (Extended Graphics Array)
b) CGA (Color Graphics Array)
c) VGA (Video Graphics Array)
d) SVGA (Super - VGA)


10. If you have an older computer, and see a DB-9 female connector on the back, it's probably a/an _______________.
a) VGA video connector
b) EGA/CGA video connector
c) XGA video connector
d) SVGA video connector


11. The number of times in one second that the image on a monitor is redrawn is called it's ____________, and is measured in Hertz (Hz).
a) dot pitch
b) refresh rate
c) interlace factor
d) resolution


12. What kind of monitor has the electron gun scan every second line in a single pass?
a) Interlaced monitor
b) Non-interlaced monitor
c) SVGA monitor
d) 17" monitor

Keyboards

     A computer's main input device is the keyboard, and it's almost impossible to imagine a computer without one. A computer keyboard looks alot like the keyboard for a typewriter but has added keys that provide many different features and enhancements. The keyboards sold today are called enhanced keyboards and have 101 to 106 individual keys. The layouts are basically the same with the odd key situated differently. They generally hook up to your computer with a DIN-5, PS2 (mini DIN-6), or USB connector.

    Keyboards can definitely have a certain feel or touch to them and it's best to try one out before you buy. Some can be quite springy while others feel kind of mushy, others have a definite snap or click to them. Some actually make a clicking sound as you type (some people might like this, it drives me nuts). There are split keyboards and ergonomic keyboards meant to help reduce the possiblity of carpal tunnel syndrome.

        Of course, you get a keyboard when you buy a computer, but it's not an overly expensive item and can easily be replaced with one more to your liking. When I say it's not an overly expensive item, I'm referring to the generic keyboards sold with the average computer system. The newer high-tech, exotic colored, ergonomic, split keyboards sporting extra buttons for the CD player and instant internet access with page-scroll and touchpad are starting to get up there in price.

     Once you've found a keyboard that you find comfortable, one of your main concerns should be proper typing form. Repetative stress injuries are a concern and poor posture can also result in back and neck pain. Sit up straight and find yourself a chair that supports the natural curve in your back. It should be adjusted to your keyboard so that you don't have to lean forward or hunch to type. Your shoulders should be relaxed with your forearms and wrists fairly level, fingers slightly curved. Wrist pads are made for you to rest your wrists on while taking short breaks, your wrists shouldn't be on them while you type. Don't sit and type constantly, try to take a few breaks every now and then and have a stretch.

Troubleshooting
    Keyboards are fairly trouble-free input devices. However, sometimes troubles do arise and there are a few relatively simple fixes.

No Response
    If you can't seem to get any response from your keyboard, the first thing to check is the connection. Make sure the connector is plugged securely into the proper port. Sometimes it's possible to plug into the wrong port if both your keyboard and your mouse use a PS2 connector. Unless it attaches with a USB connector, make sure your computer is off before you plug or unplug your keyboard or mouse. If your keyboard is unplugged when you boot your computer, you'll get a 'keyboard error' that may or may not halt your system, depending on your computer's setup. Another thing that can cause this error is if there's a key stuck down or if something is resting on a key during bootup.
     One more thing on this particular subject, computer cases used to have a keylock switch on them. They're not found on cases that often now, but some do still have them, especially network servers. This allows a person to lock out keyboard access to any unwanted users. This might be something else to check if you're not getting any response from your keyboard.

Sticking Keys
    If you have a key or several keys that stick after being pressed, it may be a little difficult to pinpoint at first, but you'll probably soon figure it out. Have you maybe spilled coffee or coke on your keyboard recently? Do you eat over it, smoke a pipe or cigarettes at your computer? It is possible to rinse a keyboard with water, let it dry thoroughly, and use it again. If it's just a couple of keys, you can pop the caps off with a chip puller and try to clean underneath. Be careful of the longer keycaps like the Enter key, Shift keys, and spacebar, they have small metal hangers under them to keep them level when pressed. It's really easy to break these if you don't know how to get them off properly. Yes, it is possible to take all the keycaps off, take the keyboard apart and wash everything down, but consider what your time is worth too. By the time you've removed all the keys, washed everything, dried it properly, and replaced the caps, a new keyboard might have been a more economical answer. Then again, if you're going to replace it anyway, why not just try rinsing it under the sink or putting it through the rinse cycle in the dishwasher without any soap. After allowing it to dry thoroughly, test it out. If it works, great, if not, buy a new one.

Change the Settings
    If you find your keyboard doing strange things, check out the Control Panel. If someone else uses your computer, maybe they've toyed with the Keyboard Settings or set some of the Accessability Options. If text is being overwritten instead of inserted when you type, check the Insert key, this toggles between insert and overwrite.

    Although not all that common, keyboards can also have electrical shorts and wiring problems. It's nice to have a spare keyboard that you can swap in and out to eliminate the possibility.

                                

F1 - F12
There are 12 function keys across the top of the keyboard. Software companies can program the individual keys to perform different functions in each application program.

Print Screen
The print screen key is to the right of the function keys. In DOS and Windows 3.x, the print screen key would send the data (text) on the screen to the printer. In Win9x, the key will send a graphical picture of the screens contents to the clipboard and it can be viewed and manipulated in any graphic program that reads .bmp files.

Scroll Lock
Beside the Print Screen key is the Scroll Lock key. In some programs, this key will lock the cursor in position and allow you to move the screen view elsewhere.

Pause
The Pause key is in the upper right corner of the keyboard. This key will halt a function or process until another key is pressed.

Shift
There is a shift key on either side of the keyboard. Pressing a key while holding down the Shift key, will produce a capital or uppercase letter or the character displayed in the upper half of the key.

Caps Lock
This key is on the left side of the keyboard. It's a toggle key  (on or off) that will produce all uppercase letters when using the alphabet keys.

Keyboards - Review

1. Which of the following are input devices only?

a)  mouse

b)  keyboard

c)  modem

d)  video card

2. The ________ key, located in the upper left corner of your keyboard, will sometimes close a text box or back you out of the current process or operation.

a)  F1

b)  ESC

c)  ENTER

d)  ALT

3. The Function Keys across the top of your keyboard can be programmed to do different functions in different applications.

a)  True

b)  False

4. What is the computer's main input device?

a)  Mouse

b)  Modem

c)  Monitor

d)  Keyboard

5. If you want to produce a character shown in the upper half of a key, or an uppercase or capital letter, you should hold down which key?

a)  ALT

b)  INS

c)  TAB

d)  SHIFT

The Mouse

The mouse is a device that translates movements on a horizontal surface into movements of a pointer on the computer screen. While thekeyboard is, by far, the most important input device attached to your computer, the mouse runs a close second, and may be the most used. 

The mouse's popularity is due, of course, to the popularity of the graphical user interface (GUI). The first mouse was developed in the mid '60s. Looking back at the early computer interfaces, and even the physical number of computers in the '60s and '70s (or lack of numbers), it's obvious that the mouse was an animal before its time. When IBM's Personal Computers hit the market in the early '80s, with the DOS command line interface, more and more people found it possible to have a computer in their home. With the introduction of menu-driven programs, the mouse began to see limited use. When the Mac GUI OS was introduced, the mouse was recognized as a valuable tool by Macintosh users, but when Microsoft mass-marketed its Windows Operating system, the mouse truly became a household word.

I've got to admit, when I first saw a GUI (Graphical User Interface), I wasn't all that impressed. I thought it seemed a little mickey-mouse-like and made the computer look more like a toy than the high-tech, effective tool that I knew it to be. When I look back at it now, I think it was more the fact that I might have felt a little cheated. It took so much time and energy to master the computer, and now it appeared as though everyone was going to be able to use a device that, up to that point, had been the semi-private realm of the techie, DOS savvy minority. And actually, that's exactly what happened. The GUI and the mouse are probably the two most important factors leading to the household personal computer being second in popularity only to the television set. (Not to mention constantly improving, lightning fast technological advancements and intelligent, aggressive push-marketing.)

The Mouse (continued)

Types of Mice
There are basically three different types of mice: mechanical, optomechanical and optical.

The mechanical mouse has a small hard rubber ball underneath that moves against two rollers as it's passed across a flat surface. Mechanical sensors detect the movement of the rollers as an 'x' and 'y' axis and the cursor on screen is moved accordingly.

An optomechanical mouse works on the same principal. The rollers have wheels on the end of them with evenly spaced holes. As the wheels spin, a light-sensitive optical device counts the number of holes that pass by and convert those numbers to an 'x' and 'y' axis.

An optical mouse is more accurate or precise and has no moving parts. It uses a laser to detect movement and has to be paired with a special pad or mat that has an embedded optical reference grid.

Mouse Connections
The serial mouse is, by far, the most popular and the easiest to install.They connect to an RS-232C serial port; one of the COM ports on the back of the computer (a DB-9 or a DB-25 male connector). A serial port is an interface that transmits one bit at a time, and RS-232C is a standard that most serial ports conform to. The fact that they do take up a COM port (and it's respective IRQ) is the biggest problem with the serial mouse. Personal Computers are very limited to the number of COM ports available.

The bus mouse was originally developed to help alleviate the problem of the COM port shortage. It connects to the computer through a small round connector (female mini-DIN-9) on the back of an expansion card installed on the motherboard. Because an expansion card had to be configured and installed on the motherboard, these mice were considered much more difficult to install. Now they are pretty well obsolete. They did free up a COM port, but they still took up an IRQ as well as an expansion slot.

The PS/2 mouse seems to be the answer to both problems. It's a type of serial mouse but it connects to a PS/2 connector (female mini-DIN-6) that is hard-wired directly to IRQ 12. It installs as simply as any serial mouse, doesn't use up a COM port, and needs no expansion card installed. Not only that, but it uses a fairly obscure IRQ that was mostly unavailable to other devices.

A cordless mouse uses infrared technology to do away with the cord. It seems like it would be a good idea because the cord on a mouse can be a real pain. It drags across the top of the desk, gets caught and hangs up in the other cords, or anything that might be lying on your desktop. They also have a receptor that must be visible to the mouse (line of sight), if anything is in the way, the mouse won't respond. This can sometimes cause a little aggrivation unless you keep a very tidy desk. Cordless mice are more expensive than other types.

The USB mouse is, by far, my favorite. With Windows98, USB has become one of the most advanced (and one of the best) connections around for mice, printers and other peripherals. Installation is simple. It's hot-swappable, so you can plug it in even when your computer is running. The mouse is immediately recognized and you can use it right away.

Care & Maintenance
The most used and abused cord on your computer is the mouse cord. It's dragged, pulled, yanked and twisted everyday with normal use. Try to provide the cord free movement as much as possible and allow a little slack at all times.

The mousepad itself can make a difference in the amount of gunk that builds up on the inside rollers. The pad with the porous cloth surface will hold all kinds of dust, grime, dead skin and moisture that tends to transfer to the rollers via the rubber ball. Get a pad that has a harder, plastic type surface. It won't get loaded up with as much crap and it's a lot easier to clean, just wipe it with a damp cloth.

If your mouse cursor seems to jump or jerk across the screen, or actually stops as though its hit a wall and doesn't seem to want to move properly, it's probably dirty. This is caused by the buildup of gunk on the rollers that was mentioned earlier. The word gunk is a highly technical computer term that refers to the grime, dust, dead skin and debris that transfers onto the mouse rollers and can build up to the point where it touches the plastic edge of the mouse and actually stops the roller from turning. This is what makes the cursor on your screen stop dead in its tracks. While this can be very frustrating, it's an easy problem to solve. To clean these rollers:

• Close out of Windows and shut the computer off.
• Disconnect the mouse and turn it upside down. You'll notice a faceplate around the ball. Remove the faceplate. It may twist a quarter turn or it may click forward (usually, there's arrows to indicate).
• Carefully turn it over and remove the ball. Don't try to see if the ball bounces! When it hits the floor, it will put it out of round and ruin it. And in case you're still wondering, they don't bounce too well at all.
• You can clean the ball with luke warm water and a lint free cloth. Don't use alcohol or cleaners on it.
• If you look inside the cavity left by the ball, you'll see the rollers. You'll also be able to see any buildup (gunk) on the rollers. Dab the buildup with a little isopropol alcohol and then gently remove the buildup with a toothpick or a small flathead screwdriver. Be careful not to scratch the rollers.
• When everything is completely dry, you can reassemble the mouse, plug it in and turn on your computer. There'll be a noticeable improvement.

As for the outside of the mouse itself, you can clean it with a damp cloth. 

The Mouse - Review

1. Which of the following are input devices only?
a)  mouse
b)  keyboard
c)  modem
d)  video card


2. The __________ is an input device that translates movements on a horizontal surface into movements of a pointer on the computer screen.
a)  keyboard
b)  printer
c)  joystick
d)  mouse


3. The Graphical User Interface or GUI (gooey) is one of the least popular computer interfaces.
a)  True
b)  False


4. This type of mouse has no moving parts and has to be paired with a special pad or mat that has an embedded optical reference grid.
a)  optomechanical
b)  PS/2
c)  optical
d)  mechanical


5. Which of the ports on the back of your computer can support a mouse? Choose all that apply.
a)  DB-9 male
b)  USB
c)  PS/2
d)  DB-25 male


6. The PS/2 mouse port is hardwired directly to ____________ .
a)  an interface card
b)  IRQ 12
c)  IRQ 4
d)  the power supply

Ports & Connectors

The various connectors and ports on the computer allow it to communicate with the many different devices and peripherals attached. Because there are so many cables and cords attached to the back of the computer, and so many different types of connectors, it often seems a little intimidating to the newer user. Although there are some devices which may use the same connector or port, the individual devices and their cords can only physically attach to one certain type of connector; so don't feel nervous about hooking your system together.

DIN Connector
The DIN connector is a small round connector, usually with a keyed slot for proper orientation. Again, it's designated as DIN-x, with 'x' representing the number of holes or pins on the connector. It comes in a couple of different sizes and it's been used on computers about as long as the DB connector has. It's a fairly popular connector because of its small size and solid connection.

The most common DIN connector would have to be the DIN-5keyboard connector. Its the largest of the DIN connectors that you're going to find on your computer and its been around for a long time. If you own a newer computer, then the DIN-5 has probably been replaced with a DIN-6 (mini-DIN or PS/2) connector.

The PS/2, or DIN-6 connector, was mainly used by Macintosh computers for the longest time (Macintosh also used a DIN-8 connector for their printer). You may hear them referred to as a mini DIN-6connector. They're smaller and more compact than the typical DIN-5 connector and have become the standard for both the keyboard and the mouse on newer PCs. If this is the case on your computer, then the two DIN-6 female ports on the back of your computer are going to look an awful lot alike, and you need to distinguish between the mouse port and the keyboard port before hooking them up. They may be color coded or they may have a little icon beside them representing their use. Whatever the case, you're not going to do any harm if you accidentally get these two devices switched. Your mouse won't work, or you'll get a keyboard error at boot up. Your first course of action for troubleshooting this type of problem should be to check the connection anyway.

Another port you could find on the back of an older computer is theDIN-9. It would be another mini DIN port with 9 sockets. A bus mouse or a hand-held scanner may use this type of port, but it's unlikely that you're going to find one on a newer computer.

RJ Connectors
The RJ connector is used for communication devices. If you live in North America and have a jack on your wall that your phone connects to, that's an RJ-11 connector. Now, the RJ-11 connector or port doesn't have 11 pins or 11 holes. As a matter of fact, it only connects 4 or 6 wires.

You may have an RJ-11 connector on the back of your computer if you have an internal modem. This is to hook a phone line up allowing communication with other computers and access to the Internet and the World Wide Web.

If you see two RJ-11 connectors side by side, it means that you can hook the phone line to your computer using the one jack, and then an extension phone can be plugged into the other jack. A lot of modems today allow for fax and voice capabilities. This means that you can fax from your computer, it can double as an answering machine that records messages and voice mail, and, if you have speakers and a microphone, you can even use it as a speakerphone.

An RJ-45 connector looks much like the RJ-11, only larger. It connects 8 wires and is used for network ethernet connections. If you see and RJ-45 connector or port on the back of your computer then there's two possibilities; Your computer is hooked up to a network or intranet, or, you have cable hookup to the Internet and the World Wide Web. The latter uses an RJ-45 connection between the cable modem and the network interface adapter (which is the same adapter you would be using for a network connection).

As you can see, the RJ connector is designated as RJ-x. But the 'x' doesn't tell you the number of connectors that the port has like other ports. At one time, I thought it might designate the size of the jack. The RJ-45 is larger than the RJ-11, but the RJ-12 is smaller (this is the connector between your phone and the handset), so I guess that doesn't hold water either. At this point, I become disinterested... If you know the answer, let me know and I might change this paragraph. But mainly what you need to know is, the RJ-11 connects 4 or 6 wires, is used on modems and telephones, and is smaller than the RJ-45 which is used for ethernet connections to network interface cards.

Centronics Connectors
The Centronics connector is a parallel interface connector. It has eight parallel data lines which allow data to travel eight bits at a time. (remember the parallel DB-25 female port). The Centronics connector is designated as Centronics-x, with 'x' representing the number of teeth or connections it has. It kind of looks like an elongated DB connector with metal teeth as connectors instead of pins. Some connectors have small clips on either side to hold it in place.

You're probably not going to find this connector on the back of your computer, but on the opposite end of your parallel cable where it connects to the printer. This will more than likely be a Centronics-36connector.

If you have SCSI or know what SCSI is, then you should know that SCSI can use a Centronics-50 or Centronics-68 connector, as well as a DB-25.

USB (Universal Serial Bus)

Universal Serial Bus is a relatively new connector that was meant to replace Serial and Parallel ports. Its a flat, keyed connector with four contacts that was designed for mid-speed peripherals such as scanners, keyboards, mice, joysticks, printers, modems and some CD-ROMs.USB is unique in that it is completely hot-swappable. In otherwords, you can plug it in or unplug it while the computer is on. Your computer should recognize it as soon as its plugged in, and you should have use of the device immediately.

USB allows you to daisy-chain up to 127 devices. This means that you could have a joystick plugged in, with a printer plugged into that, and a scanner plugged into the printer, etc...

USB was first introduced with new computers around 1997 and the final version of Win95 (SR2) provided very limited support for it. A few problems seemed to develop at first. You had to have a Pentium machine with a BIOS that supported USB, and it had to be enabled in the setup. Your computer had to have USB ports on it, or pins that allowed for the attachment of a USB interface. Aside from that, you could install a USB adapter card in one of your PCI slots. Then, there weren't a lot of USB devices out there.

I think one of the biggest problems that arose at first was that people weren't using the proper Operating System. The early versions of Win95 did not support USB. Also, a lot of machines shipped with USB ports or capabilities before the BIOS supported it completely. Updating, or flashing the BIOS could sometimes solve the problem.

Despite the growing pains, Windows 98, and computers shipped after 1998 provide excellent support for USB; and the number of devices have increased dramatically.

I have a USB mouse and scanner that I can hot swap between my desktops and my laptop with immediate access. To tell the truth, I haven't even tried daisy-chaining together, and as I write this, I'm thinking about going out and buying a keyboard just so I can try it. I think USB is fantastic, and I'm looking forward to the day when all peripherals are that easy to install and configure.

Connectors & Ports - Review

1. A lot of external devices or peripherals for your computer hook up to a serial port on the back. 
The serial ports that you may find will be ____________.
a)  DB-9 or DB-25 female connectors
b)  DB-9 or DB-25 male connectors
c)  DB-25 female connectors
d)  DB-15 female connectors


2. What is a common connector for a parallel port?
a)  RJ-45
b)  DB-25 male
c)  DB-25 female
d)  DB-15 female, in three rows of five slots


3. Which of the following can be used as SCSI connectors? Check all that apply.
a)  Centronics 50-pin connector
b)  Centronics 68-pin connector
c)  DB 15-pin male connector
d)  DB 25-pin female connector


4. RS-232 is an IEEE standard that applies to __________.
a)  parallel ports
b)  networks
c)  game ports
d)  serial ports


5. True or False. On the PC side, the printer port is usually a 25-pin female parallel connector.
a)  True
b)  False


6. A serial cable can be up to 50 feet long before data starts to lose its integrity.
a)  True
b)  False


7. Because a parallel cable can transfer data 8 bits at a time, 
it can be up to 75 feet long before data starts to lose its integrity.
a)  True
b)  False


8. Which of the following ports on the back of your computer are considered hot-swappable?
a)  RS-232
b)  USB
c)  RJ-11
d)  Mini DIN-6


9. This type of connector is sort of a 'D' shape and is sometimes referred to as a 'D-shell' connector.
a)  DB
b)  DIN
c)  Centronics
d)  USB


10. Which of the ports on the back of your computer can support a mouse? Choose all that apply.
a)  DB-9 male
b)  USB
c)  PS/2
d)  DB-25 male


11. The PS/2 mouse port is hardwired directly to ____________ .
a)  an interface card
b)  IRQ 12
c)  IRQ 4
d)  the power supply


12. If you have an older computer, and see a DB-9 female connector on the back, it's probably a/an _______________. 
a)  VGA video connector
b)  EGA/CGA video connector
c)  XGA video connector
d)  SVGA video connector


13. What is the name of the small round connector that usually has a keyed slot for proper orientation?
a)  USB
b)  DB
c)  Serial
d)  DIN


14. The RJ-11 connects 4-6 wires, is used on modems and telephones, and is smaller than the _______ , which connects 8 wires and is commonly used for ethernet connections and internet cable connections to network interface cards.
a)  RJ-45
b)  RJ-12
c)  Centronics-8
d)  DB-8


15. True or False? The Centronics connector is a serial interface connector.
a)  True
b)  False

My Computer - MCQ's 1. If you have a PC case that can be opened without the use of tools, then it is probably a ________ .  a) screwless case b) screwed case c) SnapLok case d) SnapTite case 2. The areas in your computer's case where you would install drives are called internal and external ______ . a) compartments b) trays c) bays d) bezels 3. Overvoltage is not a good thing for a computer. A device that protects against this is called an/a __________ . a) extension cord b) surge suppressor c) surge depressor d) voltage regulator 4. A lot of external devices or peripherals for your computer hook up to a serial port on the back. The serial ports that you may find will be ____________. a) DB-9 or DB-25 female connectors b) DB-9 or DB-25 male connectors c) DB-25 female connectors d) DB-15 female connectors 5. A/An ___________ format motherboard has power supplied to it  even when the computer is off. a) ATX b) Baby AT c) NLX d) XT 6. What is a common connector for a parallel port? a) RJ-45 b) DB-25 male c) DB-25 female d) DB-15 female, in three rows of five slots 7. Which of the following can be used as SCSI connectors? Check all that apply. a) Centronics 50-pin connector b) Centronics 68-pin connector c) DB 15-pin male connector d) DB 25-pin female connector 8. RS-232 is an IEEE standard that applies to __________. a) parallel ports b) networks c) game ports d) serial ports 9. Environmentally, which is the most difficult to dispose of? a) hard drives b) monitors c) power supplies d) motherboards 10. What should you use to clean the plastic cover on your monitor or PC? Choose all that apply. a) alcohol b) lint free cloth c) WD-40 d) mild soap solution   11. Which of the following are input devices only? a) mouse b) keyboard c) modem d) video card 12. True or False. On the PC side, the printer port is usually a 25-pin female parallel connector. a) True b) False 13. A serial cable can be up to 50 feet long before data starts to lose its integrity. a) True b) False 14. Because a parallel cable can transfer data 8 bits at a time, it can be up to 75 feet long before data starts to lose its integrity. a) True b) False 15. Your computer's case doesn't just store the motherboard and CPU. It also has a lot to do with the _______________. (choose all that apply.) a) expandability of your system. b) accessibility of different parts and devices. c) protection of your system. d) lifetime of your computer system. 16. The different expansion bays in your computer's case are normally  __________ and ________ inches in size. a) 3.25, 5.5 b) 5 1/2, 3 1/4 c) 3.5, 5.25 d) 6, 4 17. When you first start your computer, it goes through a series of self-tests called the POST. POST is an acronym for _________. a) Power On Self Timer b) Power On Synchronization Tests c) PC Output Synchronization Tests d) Power On Self Test 18. You can perform a warm boot on your computer by pressing CTRL+ALT+DEL. The __________ button on your computer's case performs the same function a) reset b) power c) warm boot d) voltage 19. IBM's original PC and XT computers sat flat on your desktop with the monitor on top. This is an example of the early _______ style of case. a) tower b) slimline c) tabletop d) desktop 20. Your monitor has a cable or cord that connects the monitor to a/an _________ that is installed in an expansion slot on the computer's motherboard. a) CPU b) video adapter c) VGA connector d) RJ-45 connector 21. The CRT is the picture tube of your monitor. CRT is an acronym for ____________. a) Cathode Ray Tube b) Cathode Radio Transmitter c) Video Picture Tube d) Calcidium Ray Transceiver 22. The individual dots that make up the actual picture on your computer's monitor are known as picture elements or pixels. a) True b) False 23. The number of pixels across the top of your screen times the number of pixels down the side will give you the total number of pixels used to draw the image. This is known as the monitor's ___________. a) dot pitch b) resolution c) refresh rate d) aperature 24. The ________ key, located in the upper left corner of your keyboard, will sometimes close a text box or back you out of the current process or operation. a) F1 b) ESC c) ENTER d) ALT 25. The Function Keys across the top of your keyboard can be programmed to do different functions in different applications. a) True b) False 26. A good, rigid, well built case can protect the internal components from ____________  a) dust b) vibration c) electronic interference d) all of the above 27. A computer's case is supposed to be designed so that air flows over the different components inside to help cool them down. a) True b) False 28. This computer case is the largest of the tower style cases. It has lots of room for expansion and easy access to components. a) Full Tower b) Mid Tower c) Mini Tower d) Slimline 29. This tower style case is one of the most popular. It cools better than a desktop style case but tends to be a little cramped inside with only 1 or 2 internal drive bays. a) Full Tower b) Mid Tower c) Mini Tower d) SlimTower 30. The closer pixels are to each other, the sharper the image will appear. The distance between pixels on a monitor is called it's __________ . a) refresh rate b) dot pitch c) pixelation d) resolution factor 31. IBM developed the first analog display adapter called the _________. a) XGA (Extended Graphics Array) b) CGA (Color Graphics Array) c) VGA (Video Graphics Array) d) SVGA (Super - VGA) 32. What is the computer's main input device? a) Mouse b) Modem c) Monitor d) Keyboard 33. Which of the ports on the back of your computer can support a mouse? Choose all that apply. a) DB-9 male b) USB c) PS/2 d) DB-25 male 34. The PS/2 mouse port is hardwired directly to ____________ . a) an interface card b) IRQ 12 c) IRQ 4 d) the power supply 35. If you have an older computer, and see a DB-9 female connector on the back, it's   probably a/an _______________. a) VGA video connector b) EGA/CGA video connector c) XGA video connector d) SVGA video connector 36. What is the name of the small round connector that usually has a keyed slot for proper orientation? a) USB b) DB c) Serial d) DIN 37. One gigabyte is equal to ______________ . a) 1024 kilobytes b) 1024 megabytes c) 1024 bytes d) 8 bits 38. The decimal number 64 can be represented by which binary number? a) 00100000 b) 10100000 c) 01000000 d) 11000010 39. What is the largest decimal number that can be represented using an 8-bit binary number? a) 255 b) 1024 c) 256 d) 4096 40. The binary number 00001100 can be represented by which hexidecimal number? Ch a) Dh b) 4Ch d) A1h 41. The size and shape of the circuit board, the position of the components, the position of the screw holes, and the technology incorporated, make up a motherboard's ____________ . a) configuration b) factory specs c) form factor d) OEM factor 42. What was the form factor of the original IBM PC? a) XT b) AT c) LPX d) ATX 43. The number of times in one second that the image on a monitor is redrawn is called it's ____________, and is measured in Hertz (Hz). a) dot pitch b) refresh rate c) interlace factor d) resolution 44. What kind of monitor has the electron gun scan every second line in a single pass? Interlaced monitor a) Non-interlaced monitor b) SVGA monitor c) 17" monitor 45. If you want to produce a character shown in the upper half of a key, or an uppercase or capital letter, you should hold down which key? a) ALT b) INS c) TAB d) SHIFT 46. The RJ-11 connects 4-6 wires, is used on modems and telephones, and is smaller than the _______ , which connects 8 wires and is commonly used for ethernet connections and internet cable connections to network interface cards. a) RJ-45 b) RJ-12 c) Centronics-8 d) DB-8 47. True or False? The Centronics connector is a serial interface connector. a) True b) False 48. True or False? The binary number 1101 is equal to 13 decimal. a) True b) False 49. The decimal number 15 is equal to the hexidecimal number Fh. What is the hexidecimal equivalent of decimal 16? a) Gh b) 1h c) 1Fh d) 10h 50. True or False? Hexidecimal numbers are always followed by a lowercase 'h' to designate them as hex. a) True b) False