CHARACTERISTICS OF COMPUTER
SPEED
Modern computer systems can process the data in a fraction of second to provide the desired results. Speed of different computer system is meaured in terms of mips million instructions per second. The speed of a microprocessor is measured in this unit.
RELIABILITY
Computers are widely used because of their exceptional reliability i.e. these machines are Capable of operating under adverse conditions for any time period producing consistent results.
ACCURACY
Computers can price the data accurately. They are used in space research organizations like ISRO. IF you give correct instructions and program, a computer will never give wrong results. The computing principles known as garbage in garbage out (GIGO), refers to the accuracy of computer where output depends upon the accuracy of the users input.
STORAGE
Modern computer systems have big storage media. Using any of the available storage devices, the data can be transferred quickly from the storage unit into the memory, processed and then stored again back in to the storage unit for future use.
COMMUNICATION
Today, computers can communicate with each other and share information. This is possible through communication mediums, such as moderms, telephone lines, satellite, etc. Which are used to connect each other. This connection of computer is known as networking. Today’s, Internet is a popular worldwide collection of network, that links millions of computer together globally.
Wednesday, 10 May 2017
Classifications of Computer
CLASSIFICATIONS OF COMPUTER
Computer has been classified under four main classes. These are:
1. Micro computer
2. Mini
3. Mainframe
4. Super
These categories have been distinguished according to the size, processing speed, capability and price of computer. Although with development in technology the distinction among these computers is becoming blurred. It is important to classify them, as it is sometimes useful to differentiate the key elements and architecture among them.
Micro computer
A microcomputer CPU is a microprocessor. This originated in the late 1970s. The first micro computer was built with 8 bit microprocessor chip. It was designed to be used by one person at a time. A pc is a micro computer designed for general purpose computations. It can perform various tasks. It has one input device, output device, memory and a cpu.
MINI COMPUTER
A mini computer is a fast but small and inexpensive computer with limited input/output capabilities. Mini computer provide facility for more storage and communication links between uers. They can support around 4000 connected users at a time. The first mini computer was developed by DEC(DIGITAL EQUIPMENT CORPORATION , the largest producer of mini computer.
Mainframe computer
A mainframe computer is a big computer system that has the capability of supporting many powerful peripheral devices. Mainframe are usually operated in a custom-built environment, suited for big organizations to manage high volume application. They are used as central (host) computer in network system. Libraries of applications program developed in mainframe computer are much Larger than those of te micros and mini computer.
Super computer
A super computer is the fastest machine that has the largest memory as well as multi-processing techniques, where a number of processors are used to solve a problem.
It can process 64 billion instructions per second. It is generally used in complex scientific application like weather forecasting, Computation, remote sesing, image processing, bio-edical application, research and development areas. In india, we have sray xmp-14 mainframe super computer system present at the meteorological department. India has already developed a suoer computer named PARAM 10000.
Computer has been classified under four main classes. These are:
1. Micro computer
2. Mini
3. Mainframe
4. Super
These categories have been distinguished according to the size, processing speed, capability and price of computer. Although with development in technology the distinction among these computers is becoming blurred. It is important to classify them, as it is sometimes useful to differentiate the key elements and architecture among them.
Micro computer
A microcomputer CPU is a microprocessor. This originated in the late 1970s. The first micro computer was built with 8 bit microprocessor chip. It was designed to be used by one person at a time. A pc is a micro computer designed for general purpose computations. It can perform various tasks. It has one input device, output device, memory and a cpu.
MINI COMPUTER
A mini computer is a fast but small and inexpensive computer with limited input/output capabilities. Mini computer provide facility for more storage and communication links between uers. They can support around 4000 connected users at a time. The first mini computer was developed by DEC(DIGITAL EQUIPMENT CORPORATION , the largest producer of mini computer.
Mainframe computer
A mainframe computer is a big computer system that has the capability of supporting many powerful peripheral devices. Mainframe are usually operated in a custom-built environment, suited for big organizations to manage high volume application. They are used as central (host) computer in network system. Libraries of applications program developed in mainframe computer are much Larger than those of te micros and mini computer.
Super computer
A super computer is the fastest machine that has the largest memory as well as multi-processing techniques, where a number of processors are used to solve a problem.
It can process 64 billion instructions per second. It is generally used in complex scientific application like weather forecasting, Computation, remote sesing, image processing, bio-edical application, research and development areas. In india, we have sray xmp-14 mainframe super computer system present at the meteorological department. India has already developed a suoer computer named PARAM 10000.
Generations of computer
Generations of computer
Generation of computer refer to the development of computer in different phases.
Computer have been developed in five distinct phases:
First Generations(1944-1955)
These computers were very big and heavy with large number of internal circuits.they store small amount of information. ENIAC was the first electronic computer of first generation.
Some common characteristics:
Vaccum tubes were used.
Large in size and heavy in weight.
Slow speed of operation.
Limited computing facility.
Complex maintence system.
Second Generations(1956-1965)
These computer were faster,cheaper,smaller and less expensive.They had magnetic core and magnetic disk storage for memory.
Some common characteristics:
Transistors were used.
High speed and large memory availability.
Small size and less power consuming.
Low heat production.
High level programming languages were developed and used like FORTON,COBOL,ALGOL AND SNOBOL.
Third Generation(1966-1975)
This used ICs.ICs stands for small integrated circuit.These circuit were known as chips.These circuit consisted of transistors,registers and capacitors.These computer were smaller,faster and more reliable then earlier generations computers.
Some common characteristics:
Intergrated circuits were used.
Smaller in size,lesser weight,better performance and reliability.
High level programming languages were developed like FORTAN-IV,COBOL-68,BASIC AND LOGO
Higher speed of operations in nano seconds.
Online processing such as airline reservation system was used.
FOURTH GENEERATION(1976-1985)
This generation computer used very large scale interated circuits(VLSICs).These circuit are known as microprocessors.These computer are smallest,cheapest,fastest.These computer are the most powerful with massive storage capacity.
Some common characteristics:
Mioprocessors are used.
Smallest and cheapest in price.
Very fast in speed and accuracy.
Mini,portable and super computers came under this generation.
FIFTH GENERATION(1985 onwards)
The fifth generation computer are based an ARTIFICIAL INTELLIGENCE(AI).These computers are still under development.Due to AI these computers will be intelligent to do work themselves.They will be intelligent to take decisions independently.
Some common characteristics:
Intelligent enough to do work themselves.
Self decision-making ability.
Able to understand uman language.
Generation of computer refer to the development of computer in different phases.
Computer have been developed in five distinct phases:
First Generations(1944-1955)
These computers were very big and heavy with large number of internal circuits.they store small amount of information. ENIAC was the first electronic computer of first generation.
Some common characteristics:
Vaccum tubes were used.
Large in size and heavy in weight.
Slow speed of operation.
Limited computing facility.
Complex maintence system.
Second Generations(1956-1965)
These computer were faster,cheaper,smaller and less expensive.They had magnetic core and magnetic disk storage for memory.
Some common characteristics:
Transistors were used.
High speed and large memory availability.
Small size and less power consuming.
Low heat production.
High level programming languages were developed and used like FORTON,COBOL,ALGOL AND SNOBOL.
Third Generation(1966-1975)
This used ICs.ICs stands for small integrated circuit.These circuit were known as chips.These circuit consisted of transistors,registers and capacitors.These computer were smaller,faster and more reliable then earlier generations computers.
Some common characteristics:
Intergrated circuits were used.
Smaller in size,lesser weight,better performance and reliability.
High level programming languages were developed like FORTAN-IV,COBOL-68,BASIC AND LOGO
Higher speed of operations in nano seconds.
Online processing such as airline reservation system was used.
FOURTH GENEERATION(1976-1985)
This generation computer used very large scale interated circuits(VLSICs).These circuit are known as microprocessors.These computer are smallest,cheapest,fastest.These computer are the most powerful with massive storage capacity.
Some common characteristics:
Mioprocessors are used.
Smallest and cheapest in price.
Very fast in speed and accuracy.
Mini,portable and super computers came under this generation.
FIFTH GENERATION(1985 onwards)
The fifth generation computer are based an ARTIFICIAL INTELLIGENCE(AI).These computers are still under development.Due to AI these computers will be intelligent to do work themselves.They will be intelligent to take decisions independently.
Some common characteristics:
Intelligent enough to do work themselves.
Self decision-making ability.
Able to understand uman language.
Printer
PRINTER
PRINTER is a device that accepts text and graphic output from a computer and transfer information to paper.printer vary in size,speed,sophicated and cost.It is a output device.It generally connect through power plug-in.
THE PRINTER QUALITIES ARE:
Color: Color is important for users who need to print pages for presentations or maps and other pages where color is part of the information. Color printers can also be set to print only in black-and-white. some printers are more expensive to operate since they use two ink cartridges (one color and one black ink) that need to be replaced after a certain number of pages. Users who don’t have a specific need for color and who print a lot of pages will find a black-and-white printer cheaper to operate.
Resolution: Printer resolution is usually measured in dots per inch ( dpi ). Most inexpensive printers provide sufficient resolution for most purposes at 600 dpi.
Speed: The speed of the printer becomes important. Inexpensive printers print only about 3 to 6 sheets per minute. Color printing is slower. More expensive printers are much faster.
Memory: Most printers come with a small amount of memory (for example, 1 mb) that can be expanded by the user. Having more than the minimum amount of memory is helpful and faster when printing out pages with large images or tables with lines around them.
Printers Languages
Printers languages are commands from the computer to the printers to tell the printer how to format the document being printed. These commands manage font size, graphics, compression of data sent to the printer, color etc.
TWO MOST POPULAR PRINTER LANGUAGES ARE :
Postscript and Printer Control Language.
Postscript is a printer language that uses English phrases and programmatic constructions to describe the appearance of a printed page to the printers. It introduced new features such as outline font s and vector graphics . Printers now come from the factory with or can be loaded with Postscript support.
Postscript is not restricted to printers and It can be used with any device. Devices that creates an image using dots such as screen displays, slide recorders, and image setters.
SOME COMMON THINGS SHOULD KEEP IN MIND DURING PRINTING:
If there are no lights or no display on the front of the printers. And if printer is not getting electricity or power. Then Check to make sure the power cord is plugged in .
ΓΌ The computer and the printer must be communicating before the printer will print. When you send a document to print, does a small printer appear on the Windows taskbar.
If the printers has paper in the paper tray, the paper may be jammed . Then Take the paper out of the paper tray. Also check to see that the top piece of paper is not crinkled or bent.
PRINTER is a device that accepts text and graphic output from a computer and transfer information to paper.printer vary in size,speed,sophicated and cost.It is a output device.It generally connect through power plug-in.
THE PRINTER QUALITIES ARE:
Color: Color is important for users who need to print pages for presentations or maps and other pages where color is part of the information. Color printers can also be set to print only in black-and-white. some printers are more expensive to operate since they use two ink cartridges (one color and one black ink) that need to be replaced after a certain number of pages. Users who don’t have a specific need for color and who print a lot of pages will find a black-and-white printer cheaper to operate.
Resolution: Printer resolution is usually measured in dots per inch ( dpi ). Most inexpensive printers provide sufficient resolution for most purposes at 600 dpi.
Speed: The speed of the printer becomes important. Inexpensive printers print only about 3 to 6 sheets per minute. Color printing is slower. More expensive printers are much faster.
Memory: Most printers come with a small amount of memory (for example, 1 mb) that can be expanded by the user. Having more than the minimum amount of memory is helpful and faster when printing out pages with large images or tables with lines around them.
Printers Languages
Printers languages are commands from the computer to the printers to tell the printer how to format the document being printed. These commands manage font size, graphics, compression of data sent to the printer, color etc.
TWO MOST POPULAR PRINTER LANGUAGES ARE :
Postscript and Printer Control Language.
Postscript is a printer language that uses English phrases and programmatic constructions to describe the appearance of a printed page to the printers. It introduced new features such as outline font s and vector graphics . Printers now come from the factory with or can be loaded with Postscript support.
Postscript is not restricted to printers and It can be used with any device. Devices that creates an image using dots such as screen displays, slide recorders, and image setters.
SOME COMMON THINGS SHOULD KEEP IN MIND DURING PRINTING:
If there are no lights or no display on the front of the printers. And if printer is not getting electricity or power. Then Check to make sure the power cord is plugged in .
ΓΌ The computer and the printer must be communicating before the printer will print. When you send a document to print, does a small printer appear on the Windows taskbar.
If the printers has paper in the paper tray, the paper may be jammed . Then Take the paper out of the paper tray. Also check to see that the top piece of paper is not crinkled or bent.
Scanner
SCANNER
Scanner is a device that scans documents such as photographs and pages of text.It is a input device. Scanners have become an important part of the home office over the last few years. Scanner refer to the Computer peripheral device that converts a document, film, graphic, or photograph to a digital image, manipulable through an appropriate software.
The basic principle of a scanner is to analyze an image and process it in some way. Image and text capture allow you to save information to a file on your computer. You can then alter or enhance the image and also print it out or use it on your Web page . The purpose of greater scanning resolution is to create more pixels, to create a larger image size.
EXAMPLE:
Using it can be a quick and efficient way to make a copy of a drivers license or pass port if you need that done.The cashier used a scanner on all of my grocery items so that they could input the price of the items a lot easier than entering them manually.And many more.
Using different interfaces you can connected computer to USB. Scanning process may include through software as well as hardware.
HARDWARE SCANNER:
A scanner or optical scanner is a hardware input device for a computer. It allow a user to take a printed picture, drawing, or document and convert it into a digital file (either an image or a text file) so that it can stored, viewed, and edited on a computer. This is generally include usb, firewalls etc mode of connectivity.
TYPES OF SCANNERS USED IN COMPUTER:
Sheetfed scanner – scanner that scans paper by feeding paper into the scanner.
Handheld scanner – scanner that scans information by holding the scanner and dragging it over a page you want to scan.
Card scanner – scanner designed to scan business cards.
Software scanners:
A scanner may refer to any program that scans computer files for errors. It also scan problems like anti-virus program . scans the files on the computer for any computer viruses or other malware.
.When used with an optical character recognition (OCR) software, a scanner can convert printed, typewritten (and, with some devices, handwritten) text into a digital file that can be read by aword processor.
SCANNER TECHNOLOGY IS EVERYWHERE AND USED IN MANY WAYS:
Flatbed scanners:It is also termed as desktop scanners.it is the most commonly used scanners. The flatbed scanner bed is 8.5 inches wide, so a 1200 dpi CCD sensor is an array of (1200 dpi x 8.5 inches) = 10200 pixels in one horizontal line. A wide-angle optical lens focuses the 8.5 inch image width onto a much smaller CCD chip, using mirrors to fold the long optical path inside the scanner.
A typical flatbed CCD array is perhaps 72 mm wide, with 7×7 micron cells being popular today. Most flatbed choices are 600 or 1200 dpi now, and some are 2400 dpi. Flatbed scanner specifications are stated with two numbers, like 200×2400 dpi . Flatbeds also usually specify a maximum resolution, like perhaps 9600 dpi. A scanners scans one horizontal row of pixels at a time, moving that scan line down the page with a carriage motor. The smaller dpi number is the optical resolution of the CCD sensor cells.
Sheet-fed scanners :It is similar to flatbed scanners except the document is moved and the scan head is immobile. A sheet-fed scanner lookt like a small portable printer.
Handheld scanners : It use the same basic technology as a flatbed scannerS, but rely on the user to move them instead of a motorized belt. This type of scannerS typically does not provide good image quality. However, it can be useful for quickly capturing text.
DRUM SCANNERS
It is used by the publishing industry to capture incredibly detailed images. They use a technology called a photomultiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams.
Scanner is a device that scans documents such as photographs and pages of text.It is a input device. Scanners have become an important part of the home office over the last few years. Scanner refer to the Computer peripheral device that converts a document, film, graphic, or photograph to a digital image, manipulable through an appropriate software.
The basic principle of a scanner is to analyze an image and process it in some way. Image and text capture allow you to save information to a file on your computer. You can then alter or enhance the image and also print it out or use it on your Web page . The purpose of greater scanning resolution is to create more pixels, to create a larger image size.
EXAMPLE:
Using it can be a quick and efficient way to make a copy of a drivers license or pass port if you need that done.The cashier used a scanner on all of my grocery items so that they could input the price of the items a lot easier than entering them manually.And many more.
Using different interfaces you can connected computer to USB. Scanning process may include through software as well as hardware.
HARDWARE SCANNER:
A scanner or optical scanner is a hardware input device for a computer. It allow a user to take a printed picture, drawing, or document and convert it into a digital file (either an image or a text file) so that it can stored, viewed, and edited on a computer. This is generally include usb, firewalls etc mode of connectivity.
TYPES OF SCANNERS USED IN COMPUTER:
Sheetfed scanner – scanner that scans paper by feeding paper into the scanner.
Handheld scanner – scanner that scans information by holding the scanner and dragging it over a page you want to scan.
Card scanner – scanner designed to scan business cards.
Software scanners:
A scanner may refer to any program that scans computer files for errors. It also scan problems like anti-virus program . scans the files on the computer for any computer viruses or other malware.
.When used with an optical character recognition (OCR) software, a scanner can convert printed, typewritten (and, with some devices, handwritten) text into a digital file that can be read by aword processor.
SCANNER TECHNOLOGY IS EVERYWHERE AND USED IN MANY WAYS:
Flatbed scanners:It is also termed as desktop scanners.it is the most commonly used scanners. The flatbed scanner bed is 8.5 inches wide, so a 1200 dpi CCD sensor is an array of (1200 dpi x 8.5 inches) = 10200 pixels in one horizontal line. A wide-angle optical lens focuses the 8.5 inch image width onto a much smaller CCD chip, using mirrors to fold the long optical path inside the scanner.
A typical flatbed CCD array is perhaps 72 mm wide, with 7×7 micron cells being popular today. Most flatbed choices are 600 or 1200 dpi now, and some are 2400 dpi. Flatbed scanner specifications are stated with two numbers, like 200×2400 dpi . Flatbeds also usually specify a maximum resolution, like perhaps 9600 dpi. A scanners scans one horizontal row of pixels at a time, moving that scan line down the page with a carriage motor. The smaller dpi number is the optical resolution of the CCD sensor cells.
Sheet-fed scanners :It is similar to flatbed scanners except the document is moved and the scan head is immobile. A sheet-fed scanner lookt like a small portable printer.
Handheld scanners : It use the same basic technology as a flatbed scannerS, but rely on the user to move them instead of a motorized belt. This type of scannerS typically does not provide good image quality. However, it can be useful for quickly capturing text.
DRUM SCANNERS
It is used by the publishing industry to capture incredibly detailed images. They use a technology called a photomultiplier tube (PMT). In PMT, the document to be scanned is mounted on a glass cylinder. At the center of the cylinder is a sensor that splits light bounced from the document into three beams.
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