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Monday, 4 February 2019

Pattern recognition

Pattern recognition
The ability of a computer software program to recognize aspects of an audio or visual data stream. One example of pattern recognition is OCR software, which finds the patterns of letters and numbers in an image and converts them to text.

Scanner

Scanner

A scanner may refer to any of the following:
 

1. When referring to hardware, a scanner or optical scanner is a hardware input device that optically "reads" and image and converts it into a digital signal. For example, a scanner may be used to convert a printed picture, drawing, or document (hard copy) into a digital file which can be edited on a computer. The picture shows an example of a flatbed scanner, the Epson V300.

  • How is a scanner connected?
  • Other types of computer scanners.
  • When was the first scanner created?
  • Why is a scanner an input device?

Related scanner pages.
Computer scanner help and support.


How is a scanner connected?


A scanner can be connected to a computer using many different interfaces although today is most commonly connected to a computer using a USB cable.

Firewire
Parallel
SCSI
USB


Other types of computer scanners
There are also other types of scanners that can be used with a computer.

Sheetfed scanner - scans paper by feeding it into the scanner
Handheld scanner - scans text and images by dragging the device over the page you want to scan
Card scanner - designed to scan business cards
Note: A handheld scanner should not be confused with a barcode reader.

When was the first scanner created?

The earliest forms of scanners appeared in the 1860s. However, the scanner as we know it today was created in 1957 by a man named Russell Kirsch at the United States National Bureau of Standards. The first image scanned by this device was a picture of Kirsch's son. This black and white image measured only 5x5 cm and had a resolution of 176 pixels on each side.

Why is a scanner an input device?

A computer scanner is a digitizer, which is a type of input device. It takes information from the real world (e.g., a document or picture) and converts it into digital information for a computer to store or manipulate. A scanner is only able to send information to the computer and cannot receive information from the computer like a printer (which is an output device).

Related scanner pages
Computer scanner manufacturers.
Computer scanner help and support.

 
2. When referring to software, a scanner may refer to any program that scans computer files for errors or other problems. A good example is an antivirus program, which scans the files on the computer for viruses or other malware.

Accessory, Photocopier, Picture, Scan, Scanner terms

Scanner terms

Scanner terms


Top Scanner Terms


Optical scanner
Image
Business card reader
OCR
Optical reader
TWAIN
Scan line


A
AAS

B
Business card reader

C
Card scanner


D
Digitize

E
Currently no listings

F
Flatbed scanner

G
Currently no listings

H
Handheld scanner


I
Image
ISIS

J
Currently no listings

K
Currently no listings

L
Currently no listings

M
Currently no listings

N
Currently no listings

O
OCR
Optical reader
Optical scanner

P
Currently no listings

Q
Currently no listings

R
Currently no listings

S
Scan head
Scan line
Scanner
Sheetfed scanner
Spatial digitizer

T
TET
Text Enhancement Technology
TWAIN

OCR

OCR

Short for optical character recognition or optical character reader, OCR is the process of taking an image of letters or typed text and converting it into data the computer understands. A good example is companies and libraries taking physical copies of books, magazines, or old printed material and using OCR to put them onto computers. While far from perfect, OCR is currently the best method of digitizing typed pages of text.

Methods of input
Data are generally passed to the computer by using a scanner or other hardware device, like a digital camera. Some computer fax applications use OCR to transform incoming faxes from graphics files into word processing documents.




Convert scanned images into text online

Convert scanned images into text online

Convert any scanned image into text using the free OCR online service Free OCR. The service supports any PDF, JPG, GIF, TIFF, or BMP file that is 2 MB or less in size. Once uploaded, the service will process the file and display the OCR results on the web page.

Speed up tabbed browsing with OneTab

Speed up tabbed browsing with OneTab

For those users who like to have many tabs open at the same time, they know that it can be very taxing on their RAM, thus slowing down their computer. However, there is a utility called OneTab that can reduce the RAM usage of these extra tabs by up to 95%. This app is a Google Chrome extension, but it works with Mozilla Firefox as well. OneTab can be downloaded from their website.

Auto sum shortcut key in Microsoft Excel

Auto sum shortcut key in Microsoft Excel

Quickly create a Microsoft Excel formula to get the sum of all cells by highlighting the cells you want to know the value of and pressing Alt and =(equals) together.

Use tab to autocomplete commands in the command line

Use tab to autocomplete commands in the command line

When at the MS-DOS, Windows command line or a Linux or Unix shell, typing in long file names or directories can become a burden. Use the Tab key to autocomplete the names of directories and files while in the command line. Below are a few examples of how this can be done.






MS-DOS and Windows command line users
While at the prompt, typing in one or more letters a file or directory name contains will autocomplete the name in alphabetical order. For example, when at the C:\> prompt, type the command below.

cd p

After the command above has been typed, instead of pressing the Enter key, press the Tab key. When you press the Tab key, the first directory that begins with "p" will be automatically typed into the command. Continuing to press the Tab key will cycle through all available directories, including the "Program Files" directory. This shortcut can be used any time you need to type a file name or directory in a command.

Tip: If you type one or more beginning letters for a file name or directory that does not exist in the current directory, the Tab key will not autocomplete.

Most Linux and Unix users
Depending on your variant of Linux or Unix and if you're remotely connecting to a Linux box, how the Tab key is used for autocomplete can change. However, below is a general run down on how this is commonly used in Linux. At the prompt in your home directory, type the command below.

cd p

Assuming your home directory has "public_ftp," "public_html," or another file or directory that begins with "p," you are shown all available files and directories. If you continue to type the next letter available, for example, "cd pu," the command will complete the remaining of the file name or directory up to the point there is no conflict. If you had both directories mentioned earlier in the current directory, it would autocomplete up to "public_" because there are two directories beginning with "public_". Pressing the Tab key again shows you the remaining available files beginning with "public_". If you wanted to type "public_html," add a "h" and press Tab to complete the directory name.

Application Software


Application software products are designed to satisfy a particular need of a particular environment. All software applications prepared in the computer lab can come under the category of Application software.

Application software may consist of a single program, such as Microsoft's notepad for writing and editing a simple text. It may also consist of a collection of programs, often called a software package, which work together to accomplish a task, such as a spreadsheet package.

Examples of Application software are the following −

Payroll Software
Student Record Software
Inventory Management Software
Income Tax Software
Railways Reservation Software
Microsoft Office Suite Software
Microsoft Word
Microsoft Excel
Microsoft PowerPoint

Features of application software are as follows −

Close to the user
Easy to design
More interactive
Slow in speed
Generally written in high-level language
Easy to understand
Easy to manipulate and use
Bigger in size and requires large storage space

When we type some letters or words, the computer translates them in numbers as computers can understand only numbers. A computer can understand the positional number system where there are only a few symbols called digits and these symbols represent different values depending on the position they occupy in the number.

The value of each digit in a number can be determined using −

The digit

The position of the digit in the number

The base of the number system (where the base is defined as the total number of digits available in the number system)

Decimal Number System
The number system that we use in our day-to-day life is the decimal number system. Decimal number system has base 10 as it uses 10 digits from 0 to 9. In decimal number system, the successive positions to the left of the decimal point represent units, tens, hundreds, thousands, and so on.

Each position represents a specific power of the base (10). For example, the decimal number 1234 consists of the digit 4 in the units position, 3 in the tens position, 2 in the hundreds position, and 1 in the thousands position. Its value can be written as

(1 x 1000)+ (2 x 100)+ (3 x 10)+ (4 x l)
(1 x 103)+ (2 x 102)+ (3 x 101)+ (4 x l00)
1000 + 200 + 30 + 4
1234
As a computer programmer or an IT professional, you should understand the following number systems which are frequently used in computers.

S.No.    Number System and Description
1   
Binary Number System

Base 2. Digits used : 0, 1

2   
Octal Number System

Base 8. Digits used : 0 to 7

3   
Hexa Decimal Number System

Base 16. Digits used: 0 to 9, Letters used : A- F

Binary Number System
Characteristics of the binary number system are as follows −

Uses two digits, 0 and 1

Also called as base 2 number system

Each position in a binary number represents a 0 power of the base (2). Example 20

Last position in a binary number represents a x power of the base (2). Example 2x where x represents the last position - 1.

Example
Binary Number: 101012

Calculating Decimal Equivalent −

Step    Binary Number    Decimal Number
Step 1    101012    ((1 x 24) + (0 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10
Step 2    101012    (16 + 0 + 4 + 0 + 1)10
Step 3    101012    2110
Note − 101012 is normally written as 10101.

Octal Number System
Characteristics of the octal number system are as follows −

Uses eight digits, 0,1,2,3,4,5,6,7

Also called as base 8 number system

Each position in an octal number represents a 0 power of the base (8). Example 80

Last position in an octal number represents a x power of the base (8). Example 8x where x represents the last position - 1

Example
Octal Number: 125708

Calculating Decimal Equivalent −

Step    Octal Number    Decimal Number
Step 1    125708    ((1 x 84) + (2 x 83) + (5 x 82) + (7 x 81) + (0 x 80))10
Step 2    125708    (4096 + 1024 + 320 + 56 + 0)10
Step 3    125708    549610
Note − 125708 is normally written as 12570.

Hexadecimal Number System
Characteristics of hexadecimal number system are as follows −

Uses 10 digits and 6 letters, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Letters represent the numbers starting from 10. A = 10. B = 11, C = 12, D = 13, E = 14, F = 15

Also called as base 16 number system

Each position in a hexadecimal number represents a 0 power of the base (16). Example, 160

Last position in a hexadecimal number represents a x power of the base (16). Example 16x where x represents the last position - 1

Example
Hexadecimal Number: 19FDE16

Calculating Decimal Equivalent −

Step    Binary Number    Decimal Number
Step 1    19FDE16    ((1 x 164) + (9 x 163) + (F x 162) + (D x 161) + (E x 160))10
Step 2    19FDE16    ((1 x 164) + (9 x 163) + (15 x 162) + (13 x 161) + (14 x 160))10
Step 3    19FDE16    (65536+ 36864 + 3840 + 208 + 14)10
Step 4    19FDE16    10646210
Note − 19FDE16 is normally written as 19FDE.

Sheet tab

Sheet tab

In Microsoft Excel, a sheet, sheet tab, or worksheet tab is used to display the worksheet that a user is currently editing. By clicking a worksheet tab (located at the bottom of the window), users may move between the various worksheets.

Every Excel file may have multiple worksheets, but the default number is three. These tabs are labeled "Sheet 1," "Sheet 2," and "Sheet 3." Users may add, move, and rename worksheets. Instructions on how to perform these operations are linked in the Related pages section below.

Tip: Use the shortcut key Alt+Shift+F1 to insert a new sheet while in Excel.

Cleaning the computer and its components

Cleaning the computer and its components
Cleaning your computer, components, and peripherals help keep everything in good working condition, helps prevent germs from spreading, and helps allow proper air flow. The picture shows a good example of just how dirty the inside of your computer case can get. Just looking at this picture it is immediately obvious that all the dust and dirt is going to prevent proper air flow and may even prevent the fan from working.
How often should I clean my computer?
General cleaning tips
Cleaning tools
Case cleaning
CD-ROM, DVD, and other disc drives
CD, DVD, and other discs cleaning
Fan cleaning
Hard drive cleaning
Headphones cleaning
Keyboard cleaning
Laptop cleaning
LCD/LED cleaning
CRT Monitor cleaning
Motherboard cleaning
Mouse cleaning
Printer cleaning
Scanner cleaning
Miscellaneous cleaning steps
How often should I clean my computer?
The frequency of how often you should clean your computer varies on different factors. To help you determine how often you need to clean your computer, we created the checklist below. Check each of the boxes below that apply to your computer's conditions to help determine how often you should clean the computer.
Where is the computer located?
In a home environment.    
In a clean office environment.    
In construction or industry environment.    
In school environment.    
Computer environment
Have cat or dog in the same building as computer.    
Smoke in the same building as computer.    
Smoke next to the computer.    
The computer is on the floor.    
The room with the computer has carpet.    
Eat or drink by computer.    
Who uses it?
Adult (18 and older).    
Young adults (ages 10-18) use computer.    
Pre-teen (younger than 10) use computer.    
More than one person uses computer.    
With what is checked above, clean your computer every 11 months.
General cleaning tips
Below is a listing of suggestions to follow when cleaning any computer components or peripherals as well as tips to help keep a computer clean.
Never spray or squirt any liquid onto any computer component. If a spray is needed, spray the liquid onto a cloth.
You can use a vacuum to suck up dirt, dust, or hair around the computer. However, do not use a vacuum inside your computer as it generates static electricity that can damage your computer. If you need to use a vacuum inside your computer, use a portable battery powered vacuum or try compressed air.
When cleaning a component or the computer, turn it off before cleaning.
Be cautious when using any cleaning solvents; some people have allergic reactions to chemicals in cleaning solvents, and some solvents can even damage the case. Try always to use water or a highly diluted solvent.
When cleaning, be careful to not accidentally adjust any knobs or controls. Also, when cleaning the back of the computer, if anything is connected make sure not to disconnect the plugs.
When cleaning fans, especially smaller fans, hold the fan or place something in-between the fan blades to prevent it from spinning. Spraying compressed air into a fan or cleaning a fan with a vacuum may cause damage or generate a back voltage.
Never eat or drink around the computer.
Limit smoking around the computer.
Cleaning tools
Although computer cleaning products are available, you can also use household items to clean your computer and its peripherals. Below is a listing of items you may need or want to use while cleaning your computer.
Cloth - A cotton cloth is the best tool used when rubbing down computer components. Paper towels can be used with most hardware, but we always recommend using a cloth whenever possible. However, only use a cloth when cleaning components such as the case, a drive, mouse, and keyboard. You should not use a cloth to clean any circuitry such as the RAM or motherboard.
Water or rubbing alcohol - When moistening a cloth, it is best to use water or rubbing alcohol. Other solvents may be bad for the plastics used with your computer.
Portable Vacuum - Sucking the dust, dirt, hair, cigarette particles, and other particles out of a computer can be one of the best methods of cleaning a computer. However, do not use a vacuum that plugs into the wall since it creates lots of static electricity that can damage your computer.
Cotton swabs - Cotton swaps moistened with rubbing alcohol or water are excellent tools for wiping hard to reach areas in your keyboard, mouse, and other locations.
Foam swabs - Whenever possible, it is better to use lint-free swabs such as foam swabs.
Tip: See our computer tools page for a list of other tools every technician should have.
Case cleaning
Why? Cleaning your case keeps the appearance of the computer looking new. While cleaning, if you see ventilation slots, these can be cleaned or cleared to help keep a steady airflow into the computer and keep all components cool.
Procedure: The plastic case that houses the PC components can be cleaned with a slightly damp lint-free cloth. For stubborn stains, add a little household detergent to the cloth. You should not use a solvent cleaner on plastics.
Make sure all vents and air holes are hair and lint-free by rubbing a cloth over the holes and vents. It is also helpful to take a vacuum around each of the hole, vents, and crevices on the computer. It is safe to use a standard vacuum when cleaning the outside vents of a computer.
If you are looking for steps on cleaning the inside of the computer, see the motherboard cleaning section.
CD-ROM, DVD, and other disc drive cleaning
Why? A dirty CD-ROM drive or other disc drives can cause read errors when reading discs. These read errors could cause software installation issues or issues while running the program.
Procedure: To clean the CD-ROM drive, we recommend purchasing a CD-ROM cleaner from your local computer retailer. Using a CD-ROM cleaner should sufficiently clean the CD-ROM laser from dust, dirt, and hair.
You can also use a cloth dampened with water to clean the tray that ejects from the drive. However, make sure that after the tray is cleaned that it completely dry before putting the tray back into the drive.
See the disc cleaning recommendation for further steps on cleaning each of your CDs.
Computer CD-ROM and disc drive help and support.
CD, DVD, and other discs cleaning
Why? Dirty CDs can cause read errors or cause CDs not to work at all.
Procedure: Use a cleaning kit or damp clean cotton cloth to clean CDs, DVDs, and other discs. When cleaning a disc wipe against the tracks, starting from the middle of the CD or DVD and wiping towards the outer side as shown in the picture below. Never wipe with the tracks; doing so may put more scratches on the disc.
Tip: If the substance on a CD cannot be removed using water, pure alcohol can also be used.
Hard drive cleaning
Why? Computer hard drives cannot be cleaned. However, they can be cleaned with software utilities to help it run fast and efficiently. Utilizing these utilities prevent the hard drive from slowing down.
Procedure: Refer to our basic troubleshooting section for your operating system for steps that can be done to help improve the performance of your computer.
How to clean a computer hard drive.
My computer is running slow what steps can I do to fix it?
Computer hard drive help and support.
Headphones cleaning
Why? Headphones and headsets can be used by many different people and may need to be frequently cleaned to help prevent the spreading of germs and head lice.
Procedure: If the headphones being used are plastic or vinyl, moisten a cloth with warm water and rub the head and earpieces of the headphones.
Note: If the headphones are being used for a library or school, do not use any disinfectant or cleaning solvent since some people can have allergic reactions to the chemicals they contain.
Headphones that have cushions also have the availability of having the cushions replaced. Replacing these cushions can also help keep the headphones clean.
Finally, in regards to headphones spreading head lice. If different students use the same headphones, have students use their own headphones, place bags over the headphones, or using headphones that can be wiped with warm water after each use.
Keyboard cleaning
These steps are for cleaning a desktop keyboard. See the cleaning a laptop keyboard page for laptop steps.
Dust, dirt, and bacteria
The computer keyboard is usually the most germ infected items in your home or office. A keyboard may even contain more bacteria than your toilet seat. Cleaning it helps remove any dangerous bacteria and keeps the keyboard working properly.
Procedure: Before cleaning the keyboard, first turn off the computer or if you are using a USB keyboard unplug it from the computer. Not unplugging the keyboard can cause other computer problems as you may press keys that cause the computer to perform a task you do not want it to perform.
Many people clean the keyboard by turning it upside down and shaking. A more efficient method is to use compressed air. Compressed air is pressurized air contained in a can with a very long nozzle. To clean a keyboard using compressed air aim between the keys and blow away all of the dust and debris that has gathered there. A vacuum cleaner can also be used, but make sure the keyboard does not have loose "pop off" keys can be sucked up by the vacuum.
If you want to clean the keyboard more extensively, remove the keys from the keyboard.
After the dust, dirt, and hair have been removed. Spray a disinfectant onto a cloth or use disinfectant cloths and rub each of the keys on the keyboard. As mentioned in our general cleaning tips, never spray any liquid onto the keyboard.
Substance spilled into the keyboard
If the keyboard has anything spilled on it (e.g., pop, cola, Pepsi, Coke, beer, wine, coffee, and milk), not taking the proper steps can destroy the keyboard.
Procedure: Below is recommendations that can help prevent a keyboard from becoming bad after something has spilled into the keys.
If anything is spilled onto the keyboard turn the computer off immediately or at the very least disconnect the keyboard from the computer. Once done flip the keyboard over to prevent the substance from penetrating circuits. While the keyboard is upside down, shake the keyboard over a surface that can be cleaned later. While still upside down, use a cloth to start cleaning the keys. After the keyboard has been cleaned, leave the keyboard upside down for at least two days allowing it to dry. Once dry, continue cleaning the keyboard with any remaining substance.
If after cleaning the keyboard keys are sticking, remove the keys and clean below the keys and the bottom portion of the key.
Finally, if the keyboard still works but remains dirty or sticky before discarding the keyboard as a last resort try washing the keyboard in the dishwasher.
If after doing all the above steps the keyboard still does not work, we recommend buying a new keyboard.
Computer keyboard help and support.
LCD/LED cleaning
Why? Dirt, dust, and fingerprints can cause the computer screen to be difficult to read.
Procedure: Unlike a CRT computer monitor, the LCD or LED monitor is not glass and requires special cleaning procedures.
When cleaning the LCD or LED screen, it is important to remember to not spray any liquids onto the screen directly. Press gently while cleaning and do not use a paper towel since it can scratch the screen.
To clean the LCD or LED screen, use a non-rugged microfiber cloth, soft cotton cloth, or Swiffer duster. If a dry cloth does not completely clean the screen, you can apply rubbing alcohol to the cloth and wipe the screen with a damp cloth. Rubbing alcohol is used to clean LCD and LED monitors before it leaves the factory.
Computer flat-panel and LCD help and support.
CRT monitor cleaning
Tip: This section is for CRT computer monitors. If you have a flat screen monitor, see the LCD/LED cleaning section.
Why? Dirt, dust, and fingerprints can cause the computer screen to be difficult to read.
Procedure: A glass monitor screen can be cleaned with ordinary household glass cleaner. Be sure to unplug the power cord from the monitor and spray the cleaner onto a lint-free cloth so the fluid does not leak into the electrical components inside the monitor. Vacuum off any dust that has settled on top of the monitor and make sure no books or papers are covering the air vents. Obstructed monitor vents can cause the monitor to overheat or even catch on fire.
Caution: We suggest only using a cloth dampened with water when cleaning non-glass monitors or any anti-glare screens. Using ordinary household glass cleaner on special screens, especially cleaners with ammonia, can remove anti-glare protection or other special surfaces.
Other good cleaning solutions
Microfiber Towels
Swiffer Dusters
Related pages
Computer monitor help and support.
Motherboard cleaning
Why? Dust and especially particles of cigarette smoke can build up and corrode circuitry, causing various problems such as computer lockups.
Caution: When inside the computer, take the necessary ESD precautions and try to avoid unplugging any cables or other connections.
Procedure: Our recommendation when cleaning the motherboard from dust, dirt, or hair is to use compressed air. When using compressed air, hold it in the upright position to prevent any of the chemicals from coming out of the container, which may damage or corrode the motherboard or other components. Also, ensure when using compressed air that you always blow the dust or dirt away from the motherboard or out of the case.
Another good alternative to compressed air is a portable battery powered vacuum. Portable vacuums can effectively remove the dust, dirt, and hair from the motherboard completely and prevent it from getting trapped in the case.
Warning: Never use an electrically powered vacuum, as it can cause lots of static electricity that can damage the computer. When using a vacuum, keep it a couple of inches away from the motherboard and other components to prevent damage and anything from being sucked into the vacuum (e.g., jumpers or small cables).
Tip: When cleaning the inside of the case, also look at any fans or heat sinks. Dust, dirt, and hair can collect around these components the most.
Computer motherboard help and support.
Computer mouse cleaning
Optical or laser mouse
Why? A dirty optical or laser mouse can cause the mouse cursor to be difficult to move or move erratically.
Procedure: Use a can of compressed air that is designed for use with electronic equipment, spraying around the optical sensor on the bottom of the mouse. Blowing air on the bottom of the mouse clears away any dirt, dust, hair, or other obstructions that may be blocking the optical sensor.
Avoid using any cleaning chemicals or wiping a cloth directly on the optical sensor, as it could scratch or damage the optical sensor.
Optical-mechanical (ball) mouse
Why? A dirty optical-mechanical mouse (mouse with a ball) can cause the mouse to be difficult to move, as well as cause strange mouse movement.
Procedure: To clean the rollers of an optical-mechanical mouse, you must first remove the bottom cover of the mouse. To do this, examine the bottom of the mouse to see what direction to rotate the cover. As you can see in the below illustration, the mouse cover must be moved counterclockwise. Place two fingers on the mouse cover, push down and rotate in the direction of the arrows.
Once the cover has rotated about an inch, rotate the mouse into its normal position, covering the bottom of the mouse with one hand. The bottom should then fall off, including the mouse ball. If the cover does not fall off, try shaking the mouse gently.
Once the bottom cover and the ball is removed, you should be able to see three rollers located inside the mouse. Use a cotton swab, finger, or fingernail to remove any substances on the rollers. Usually, there is a small line of hair and dirt in the middle of the roller. Remove as much of this substance as possible.
Once you have removed as much dirt and hair as possible, set the ball back in the mouse and place the cover back on.
If the mouse still has the same problems, repeat the above process. If after several attempts the mouse is still having the same problems, your mouse has other hardware issues and should be replaced.
Note: Cleaning your mouse pad with a damp cloth can also help improve a computer's mouse movement.
All types of mice
Why? To help keep the mouse clean and germ-free.
Procedure: Use a cloth moistened with rubbing alcohol or warm water and rub the surface of the mouse and each of its buttons.
Computer mouse help and support.
Printer cleaning
Why? Cleaning the outside of a printer can help keep the printer's appearance looking good and if used by many different people keep the printer clean of germs.
Procedure: First, make sure to turn off the printer before cleaning it. Dampen a cloth with water or rubbing alcohol and wipe the case and each of the buttons or knobs on the printer. As mentioned earlier, never spray any liquid directly onto the printer.
Why? Some printers require the inside to be cleaned to help keep the printer running smoothly.
Computer printer help and support.
Computer scanner cleaning
Why? Flatbed scanners commonly become dirty with dust, fingerprints, and hair. When the scanner is dirty, the images may have distortions.
Procedure: Clean a flatbed scanner's surface by spraying a window cleaner onto a paper towel or cotton cloth and wipe the glass until clean. As mentioned earlier, never spray a liquid directly onto the component.
The same towel or cotton cloth can also be used to clean the outside of the scanner.
Computer scanner help and support.
Miscellaneous cleaning steps
Below is a listing of miscellaneous computer hardware that is rarely used today, but kept on this page people working on older computers and need to clean these devices.
Floppy drive cleaning
Why? Dirty read/write heads on the floppy drive can cause errors during the reading or writing process.
Procedures: The floppy drive is cleaned two different ways. The first method of cleaning a floppy drive is to purchase a kit at your local retail store designed to clean the read/write heads on your floppy drive.
The second method of cleaning the floppy drive is only recommended for experienced computer users. Open the floppy drive casing and physically swab the read/write heads with a lint-free foam swab soaked in pure alcohol or trichloroethane. When performing these steps, be extremely careful when cleaning the heads to ensure that you do not lock them out of alignment causing the floppy drive not to work. To help prevent the heads from becoming out of alignment, use a dabbing motion lightly putting the swab on the head and removing it, do not perform a side-to-side motion with the swab.
Computer floppy drive help and support.
Palm pilot cleaning
Why? Dirty touch screens can cause difficult navigation.
Procedure: To clean the PalmPilot screen, use a soft cloth moistened with rubbing alcohol and rub the screen and the casing of the palm pilot. It is not recommended to use glass cleaner as it could damage plastics over time.
SuperDisk and LS120 cleaning
Why? Cleaning the SuperDisk and LS120 prevents the drive heads from becoming dirty.
Procedure: Purchase the SuperDisk cleaning kit available through Imation. Using any other method voids the warranty on your drive.

Step-by-step guide to Android development with Eclipse

Step-by-step guide to Android development with Eclipse

Learn how to create applications in an Android development environment in this guide.
In this tutorial, you will learn to create a simple application of a game
As easy as it might seem, it requires some hard work on your part before you can create an app that runs without errors. If you are reading this tutorial, it means you are probably new to the Android app development field. Don't worry -- we will divide this tutorial into different parts to make it easy for you.
Set up the Android development environment
Setting up Android development environment takes some time at first. It helps to make sure you don’t do anything wrong to save yourself from the agony of doing the whole process again.

You're required to have Windows XP or later, or Mac OS X 10.5.8 or a later version to start Android application development process. Then, there are four tools that you will need and they are available on the Internet for free:

Java JDK5 or JDK6
Android SDK
Eclipse IDE for Java Developers (optional)
Android Development Tools (ADT) Eclipse Plugin (optional)
Step 1: Setup Java Development Kit (JDK)
You can download the JDK and install it, which is pretty easy. After that, you just have to set PATH and JAVA_HOME variables to the folder where you have java and javac.

Note for Windows Users: If you installed the JDK in C:\jdk1.6.0_15 then you will have to add the following two lines in your C:\autoexec.bat file.

set PATH=C:\jdk1.6.0_15\bin;%PATH%
set JAVA_HOME=C:\jdk1.6.0_15

Step 2: Configure Android SDK
After you have successfully installed the Android SDK, it is time to configure it. After installing the Android SDK, you will get a window like this:





Just de-select the Documentation for Android SDK and Samples for SDK packages if you want to reduce the installation size and time. Click on Install 7 packages to continue with the installation. You will get a dialogue box like this:







It will take some time to install, so in the meanwhile you could do some other task to kill the time. How long will it take? Well, it depends on the speed of your Internet connection. Once it is done, you can close the SDK manager.

Step 3: Setup Eclipse IDE
Install the latest version of Eclipse. After successful installation, it should display a window like this:









Step 4: Setup Android Development Tools (ADT) Plugin
Here you will learn to install the Android Development Tool plugin for Eclipse. To do this, you have to click on Help > Software Updates > Install New Software. This will display the following dialogue box.








Just click on the Add button as shown in the picture and add https://dl-ssl.google.com/android/eclipse/ as the location. When you press OK, Eclipse will start to search for the required plug-in and finally it will list the found plug-ins.










Step 5: Create Android Virtual Device
The last step is to create Android Virtual Device, which you will use to test your Android applications. To do this, open Eclipse and Launch Android AVD Manager from options Window > AVD Manager and click on New which will create a successful Android Virtual Device. Use the screenshot below to enter the correct values.

Voila! You have successfully created Android Application Development environment. You are now ready to create a simple Rock Paper Scissors Android App.

Before we write the code, you need to know how to take input from the user. The most efficient way of taking input from the user is to use the Scanner class, which is found in the java.io package as it is just a two-step process.









Calling the Java code in Eclipse
We will save you the trouble of writing the java code for a simple Rock Paper Scissors app and use can use the code below, but you are free to use your own code if you prefer.


// Android Rock Paper Scissors App
// Rock_Paper_Scissors
// *************

import java.util.Scanner;
import java.util.Random;


public class Rock
{
public static void main(String[] args)
{
    String personPlay; //User's play -- "R", "P", or "S"
    String computerPlay = ""; //Computer's play -- "R", "P", or "S"
    int computerInt; //Randomly generated number used to determine
                     //computer's play
    String response;


    Scanner scan = new Scanner(System.in);
    Random generator = new Random();

    System.out.println("Hey, let's play Rock, Paper, Scissors!\n" +
                       "Please enter a move.\n" + "Rock = R, Paper" +
                       "= P, and Scissors = S.");

    System.out.println();

    //Generate computer's play (0,1,2)
    computerInt = generator.nextInt(3)+1;

    //Translate computer's randomly generated play to
    //string using if //statements

    if (computerInt == 1)
       computerPlay = "R";
    else if (computerInt == 2)
       computerPlay = "P";
    else if (computerInt == 3)
       computerPlay = "S";


    //Get player's play from input-- note that this is
    // stored as a string
    System.out.println("Enter your play: ");
    personPlay = scan.next();

    //Make player's play uppercase for ease of comparison
    personPlay = personPlay.toUpperCase();

    //Print computer's play
    System.out.println("Computer play is: " + computerPlay);


    //See who won. Use nested ifs

    if (personPlay.equals(computerPlay))
       System.out.println("It's a tie!");
    else if (personPlay.equals("R"))
       if (computerPlay.equals("S"))
          System.out.println("Rock crushes scissors. You win!!");
    else if (computerPlay.equals("P"))
            System.out.println("Paper eats rock. You lose!!");
    else if (personPlay.equals("P"))
       if (computerPlay.equals("S"))
       System.out.println("Scissor cuts paper. You lose!!");
    else if (computerPlay.equals("R"))
            System.out.println("Paper eats rock. You win!!");
    else if (personPlay.equals("S"))
         if (computerPlay.equals("P"))
         System.out.println("Scissor cuts paper. You win!!");
    else if (computerPlay.equals("R"))
            System.out.println("Rock breaks scissors. You lose!!");
    else
         System.out.println("Invalid user input.");


Now calling the Java code in Eclipse is a tricky process and it helps to pay attention while you're doing this. Launch Eclipse and click File > New > Java Project








When the Create a Java Project box appears, it's time to give your project a name. Click on Finish to save it and it should appear in the Package Explorer window. Then we are supposed to add a package which will contain all our package files. Click on New Java Package icon to do this, as shown in the screenshot below.





Name your project and then click Finish.









Now we need to add a Java Class, which is as easy as adding a Java Package.









After giving it a name, make sure that the following options are checked:



After you create a new class, it will show up in the Work Space where you can write or copy the code.

Congratulations! You have just finished writing your first Java Application in Eclipse. It wasn’t that difficult was it?

Now you need to build the application and to do this, Right Click on your Android Project and select Android Tools->Export Signed Application Package. After selecting the export button, select Create new keystore and it will take you to the location where you want to save it, so give it a name and save it. Fill in all the required fields that are self-explanatory and save it. You have successfully exported the apk file to your computer and you can test the app it on your android device.

Testing
Testing is as important as developing the app because your app will be of no use if it doesn't run properly or shows errors. Luckily, there is an integrated testing framework in Android Framework, which you can use to test all the aspects of your application. SDK tools can also help set up and test applications. SDK will help you test different aspects of your app no matter if you are planning on running your tests within an emulator or any Android device.

I will recommend using ADT for the testing process, as it is comparatively easier than the other tools. Using ADT, you can easily create a test project and link it to the application under test. The great thing about the ADT is that it automatically adds the necessary <instrumentation> element in the test package's manifest file.

To create a test project in Eclipse with ADT
Launch Eclipse from the Start Menu and click on File > New > Other and from the drop-down menu, click on Android Test Project, then at the bottom of the dialog click Next. Enter any name you want and in the Test Target panel, set An Existing Android Project and browse to the Rock Paper Scissors app you made. Now you should be able to see the wizard completing the Test Target Package, Application Name, and Package Name fields for you.

Choose the Android SDK platform from the Build Target Panel that the application to be tested is using. Click the Finish button to complete the Wizard and if it is disabled, look for error messages at the top to fix any problems.

If you are looking for a step-by-step guide to Android testing, you will find this Activity Testing Tutorial very useful.

Friday, 1 February 2019

MOVING AHEAD WITH HTML


SCROLL value

The SCROLL value is used for moving the text from one corner of the margin to the other margin completely.. BY defaul the text scrolls from one corner to another corner. The code for specifying the behavior attribute as scroll is given below.

<BODY>  <MARQUEE BEHAVIOR  = SCROLL>  INTRODUCTION TO HTML </MARQUEE></BODY>

SLIDE value

The SLIDE value is used for moving the text from one margin and stop as soon as the text.....

Good Morning Beautiful

Do you know????

Do you know????
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