Introduction
General-purpose computer – the electronic chips contain programs that allow the user to perform a range of complex processes and calculations.
Computer is an electronic device which capable of solving problems and manipulating data. A general-purpose computer is defined as an electronic device that:
· operates under the control of a set of instructions, called a program, that is stored in its memory
· accepts data supplied by a user
· manipulates the data according to the programmed instructions
· produces the results (information)
· stores the results (information) for future use
A computer is an electronic device, operating under the control of instructions stored in its own memory, that can accept data (input), process the data according to specified rules (process), produce results (output), and store the results (storage) for future use
The Information Processing Cycle
Using a computer to convert data into useful information is referred to as information processing (also called data processing). Processing data into information involves four basic functions:
· input – data entered into a computer for processing
· processing – the manipulation of data according to program instructions
· output – the creation of information resulting from processing
· storage – the retention of processed data on a storage medium for future use
Collectively, these steps are known as the information processing cycle.
Characteristics of Computers
Speed
Computers operate with lightening-like speed, and processing speeds are increasing as new and improved models are introduced.
Contemporary personal computers are capable of executing billions of instructions per second and larger computers,
such as supercomputers, can execute trillions of instructions per second.
Accuracy
Computers are extremely accurate when accurate programs and data are entered and processed correctly. The popular expression garbage-in, garbage-out (GIGO) means that if inaccurate programs and data are entered into a computer for processing, the resulting output will also be inaccurate.
Diligence
* A computer is a lack of concentration.
* It can work for hours without creating any error
* Due to this capability it overpowers human being in routine type of work.
Versatility
Computers are perhaps the most versatile of all machines or devices. They can perform a variety of personal, business, and scientific applications. Computers are frequently used by families, banks, retailers, manufacturers, schools, government agencies, hospitals, and scientific organizations for a variety of useful and important applications.
Storage
A computer is capable of accepting and storing programs and data. Computers can store huge amounts of data and, once stored in a computer, users can access programs and data again and again to process different data.
Power of Remembering
Any amount of information can be stored in computer and recalled as long as you require it, for any numbers of years.
It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.
No Feeling
* It does not have feelings ,
* It does not get tired even after long hours of work.
No IQ (intelligence quotient)
Computer is a dumb machine and it cannot do any work without instruction from the user and it cannot take its own decision as you can
Communications
Most modern computers contain special equipment and programs that allow them to communicate with other computers through telephone lines, cable connections, and satellites. Computers having this capability are often linked together so users can share programs, data, information, and equipment such as a printer. The structure in which computers are linked together is called a network
Evolution of Computers
The abacus was an early aid for mathematical computations. Its only value is that it aids the memory of the human performing the calculation. A skilled abacus operator can work on addition and subtraction problems at the speed of a person equipped with a hand calculator (multiplication and division are slower). The abacus is often wrongly attributed to China. In fact, the oldest surviving abacus was used in 300 B.C. by the Babylonians. The abacus is still in use today, principally in the Far East.
In 1617 an eccentric Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. The magic ingredient is the logarithm of each operand, which was originally obtained from a printed table. But Napier also invented an alternative to tables, where the logarithm values were carved on ivory sticks which are now called Napier’s Bones.
Napier’s invention led directly to the slide rule, first built in England in 1632 and still in use in the 1960’s by the NASA engineers of the Mercury, Gemini, and Apollo programs which landed men on the moon.
Leonardo da Vinci (1452-1519) made drawings of gear-driven calculating machines but apparently never built any.
The first gear-driven calculating machine to actually be built was probably the calculating clock, so named by its inventor, the German professor Wilhelm Schickard in 1623. This device got little publicity because Schickard died soon afterward in the bubonic plague.
In 1642 Blaise Pascal, at age 19, invented the Pascaline as an aid for his father who was a tax collector. Pascal built 50 of this gear-driven one-function calculator (it could only add) but couldn’t sell many because of their exorbitant cost and because they really weren’t that accurate (at that time it was not possible to fabricate gears with the required precision).
Just a few years after Pascal, the German Gottfried Wilhelm Leibniz (co-inventor with Newton of calculus) managed to build a four-function (addition, subtraction, multiplication, and division) calculator that he called the stepped reckoner
In 1801 the Frenchman Joseph Marie Jacquard invented a power loom that could base its weave (and hence the design on the fabric) upon a pattern automatically read from punched wooden cards, held together in a long row by rope. Descendents of these punched cards have been in use ever since
By 1822 the English mathematician Charles Babbage was proposing a steam driven calculating machine the size of a room, which he called the Difference Engine. This machine would be able to compute tables of numbers, such as logarithm tables. He obtained government funding for this project due to the importance of numeric tables in ocean navigation.
And by then was on to his next brainstorm, which he called the Analytic Engine. This device, large as a house and powered by 6 steam engines, would be more general purpose in nature because it would be programmable, thanks to the punched card technology of Jacquard. But it was Babbage who made an important intellectual leap regarding the punched cards.
Hollerith’s invention, known as the Hollerith desk, consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count
Hollerith built a company, the Tabulating Machine Company which, after a few buyouts, eventually became International Business Machines, known today as IBM.
Mark I computer which was built as a partnership between Harvard and IBM in 1944. This was the first programmable digital computer made in the U.S. But it was not a purely electronic computer. Instead the Mark I was constructed out of switches, relays, rotating shafts, and clutches. The machine weighed 5 tons, incorporated 500 miles of wire, was 8 feet tall and 51 feet long, and had a 50 ft rotating shaft running its length, turned by a 5 horsepower electric motor. The Mark I ran non-stop for 15 years,
ENIAC, which stood for Electronic Numerical Integrator and Calculator. ENIAC was built at the University of Pennsylvania between 1943 and 1945 by two professors, John Mauchly and the 24 year old J. Presper Eckert
Once ENIAC was finished and proved worthy of the cost of its development, its designers set about to eliminate the obnoxious fact that reprogramming the computer required a physical modification of all the patch cords and switches. It took days to change ENIAC’s program. Eckert and Mauchly’s next teamed up with the mathematician John von Neumann to design EDVAC, which pioneered the stored program. Because he was the first to publish a description of this new computer
By the end of the 1950’s computers were no longer one-of-a-kind hand built devices owned only by universities and government research labs. Eckert and Mauchly left the University of Pennsylvania over a dispute about who owned the patents for their invention. They decided to set up their own company. Their first product was the famous UNIVAC computer, the first commercial (that is, mass produced) computer. In the 50’s, UNIVAC (a contraction of “Universal Automatic Computer”) was the household word for “computer” just as “Kleenex” is for “tissue”. The first UNIVAC was sold, appropriately enough, to the Census bureau. UNIVAC was also the first computer to employ magnetic tape.
A microprocessor (uP) is a computer that is fabricated on an integrated circuit (IC). Computers had been around for 20 years before the first microprocessor was developed at Intel in 1971.
1642 – Blaise Pascal invents mechanical calculator (counting device)
1830- Charles’s Babbages “Difference Engine”
First Steam-powered “Analytical Engine”
1880’s- John H. Patterson’s Mechanical cash register (NCR)
First applications for computing devices
1930’s- Claude Shannon: Suggests use of Binary system for use with electronic circuits
1940s- John Von Neumann:Proposes reconfigurable computing by storing programs in memory
1940s – 1950s: First electronic computers,
Vacuum tubes & mechanical relays: UNIVAC, ENIAC
- 30 tons
- 150KWatt
- 80 bytes of memory
ILLIAC (Metze et. al. play Illinois fight song on accumulator bit. – first computer music)
1948- John Bardeen, Walter Brattain, William Schockley file patent on invention of the transistor
1958- Jack Kilby: introduces concept of “Integrated Circuit”
1960s- Computers begin to use transistors.
1965- Gordon Moore
* Observes that every chip produced contained roughly twice as much capacity as its predecessor and that chips new generations of chips were being released every 18-24 months.
Late 1960s- IBM mainframes
- Powerful, centralized CPUs with terminals
- Age of the “big iron”
1970s- DEC PDP-11s
- Low-cost Mini-computers
- Age of the “Vaxen”
1974- Microprocessors
- Intel introduces the 8080 (a “toy”)
- Bill Gates sophmore year at Harvard
1974- Altair 8800
-8080 CPU
-Affordable ($379 kit)
-No screen (LEDs on front panel)
-No keyboard (DIP switches on front panel)
-No storage
-4k memory.
General-purpose computer – the electronic chips contain programs that allow the user to perform a range of complex processes and calculations.
Computer is an electronic device which capable of solving problems and manipulating data. A general-purpose computer is defined as an electronic device that:
· operates under the control of a set of instructions, called a program, that is stored in its memory
· accepts data supplied by a user
· manipulates the data according to the programmed instructions
· produces the results (information)
· stores the results (information) for future use
A computer is an electronic device, operating under the control of instructions stored in its own memory, that can accept data (input), process the data according to specified rules (process), produce results (output), and store the results (storage) for future use
The Information Processing Cycle
Using a computer to convert data into useful information is referred to as information processing (also called data processing). Processing data into information involves four basic functions:
· input – data entered into a computer for processing
· processing – the manipulation of data according to program instructions
· output – the creation of information resulting from processing
· storage – the retention of processed data on a storage medium for future use
Collectively, these steps are known as the information processing cycle.
Characteristics of Computers
Speed
Computers operate with lightening-like speed, and processing speeds are increasing as new and improved models are introduced.
Contemporary personal computers are capable of executing billions of instructions per second and larger computers,
such as supercomputers, can execute trillions of instructions per second.
Accuracy
Computers are extremely accurate when accurate programs and data are entered and processed correctly. The popular expression garbage-in, garbage-out (GIGO) means that if inaccurate programs and data are entered into a computer for processing, the resulting output will also be inaccurate.
Diligence
* A computer is a lack of concentration.
* It can work for hours without creating any error
* Due to this capability it overpowers human being in routine type of work.
Versatility
Computers are perhaps the most versatile of all machines or devices. They can perform a variety of personal, business, and scientific applications. Computers are frequently used by families, banks, retailers, manufacturers, schools, government agencies, hospitals, and scientific organizations for a variety of useful and important applications.
Storage
A computer is capable of accepting and storing programs and data. Computers can store huge amounts of data and, once stored in a computer, users can access programs and data again and again to process different data.
Power of Remembering
Any amount of information can be stored in computer and recalled as long as you require it, for any numbers of years.
It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.
No Feeling
* It does not have feelings ,
* It does not get tired even after long hours of work.
No IQ (intelligence quotient)
Computer is a dumb machine and it cannot do any work without instruction from the user and it cannot take its own decision as you can
Communications
Most modern computers contain special equipment and programs that allow them to communicate with other computers through telephone lines, cable connections, and satellites. Computers having this capability are often linked together so users can share programs, data, information, and equipment such as a printer. The structure in which computers are linked together is called a network
Evolution of Computers
The abacus was an early aid for mathematical computations. Its only value is that it aids the memory of the human performing the calculation. A skilled abacus operator can work on addition and subtraction problems at the speed of a person equipped with a hand calculator (multiplication and division are slower). The abacus is often wrongly attributed to China. In fact, the oldest surviving abacus was used in 300 B.C. by the Babylonians. The abacus is still in use today, principally in the Far East.
In 1617 an eccentric Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. The magic ingredient is the logarithm of each operand, which was originally obtained from a printed table. But Napier also invented an alternative to tables, where the logarithm values were carved on ivory sticks which are now called Napier’s Bones.
Napier’s invention led directly to the slide rule, first built in England in 1632 and still in use in the 1960’s by the NASA engineers of the Mercury, Gemini, and Apollo programs which landed men on the moon.
Leonardo da Vinci (1452-1519) made drawings of gear-driven calculating machines but apparently never built any.
The first gear-driven calculating machine to actually be built was probably the calculating clock, so named by its inventor, the German professor Wilhelm Schickard in 1623. This device got little publicity because Schickard died soon afterward in the bubonic plague.
In 1642 Blaise Pascal, at age 19, invented the Pascaline as an aid for his father who was a tax collector. Pascal built 50 of this gear-driven one-function calculator (it could only add) but couldn’t sell many because of their exorbitant cost and because they really weren’t that accurate (at that time it was not possible to fabricate gears with the required precision).
Just a few years after Pascal, the German Gottfried Wilhelm Leibniz (co-inventor with Newton of calculus) managed to build a four-function (addition, subtraction, multiplication, and division) calculator that he called the stepped reckoner
In 1801 the Frenchman Joseph Marie Jacquard invented a power loom that could base its weave (and hence the design on the fabric) upon a pattern automatically read from punched wooden cards, held together in a long row by rope. Descendents of these punched cards have been in use ever since
By 1822 the English mathematician Charles Babbage was proposing a steam driven calculating machine the size of a room, which he called the Difference Engine. This machine would be able to compute tables of numbers, such as logarithm tables. He obtained government funding for this project due to the importance of numeric tables in ocean navigation.
And by then was on to his next brainstorm, which he called the Analytic Engine. This device, large as a house and powered by 6 steam engines, would be more general purpose in nature because it would be programmable, thanks to the punched card technology of Jacquard. But it was Babbage who made an important intellectual leap regarding the punched cards.
Hollerith’s invention, known as the Hollerith desk, consisted of a card reader which sensed the holes in the cards, a gear driven mechanism which could count
Hollerith built a company, the Tabulating Machine Company which, after a few buyouts, eventually became International Business Machines, known today as IBM.
Mark I computer which was built as a partnership between Harvard and IBM in 1944. This was the first programmable digital computer made in the U.S. But it was not a purely electronic computer. Instead the Mark I was constructed out of switches, relays, rotating shafts, and clutches. The machine weighed 5 tons, incorporated 500 miles of wire, was 8 feet tall and 51 feet long, and had a 50 ft rotating shaft running its length, turned by a 5 horsepower electric motor. The Mark I ran non-stop for 15 years,
ENIAC, which stood for Electronic Numerical Integrator and Calculator. ENIAC was built at the University of Pennsylvania between 1943 and 1945 by two professors, John Mauchly and the 24 year old J. Presper Eckert
Once ENIAC was finished and proved worthy of the cost of its development, its designers set about to eliminate the obnoxious fact that reprogramming the computer required a physical modification of all the patch cords and switches. It took days to change ENIAC’s program. Eckert and Mauchly’s next teamed up with the mathematician John von Neumann to design EDVAC, which pioneered the stored program. Because he was the first to publish a description of this new computer
By the end of the 1950’s computers were no longer one-of-a-kind hand built devices owned only by universities and government research labs. Eckert and Mauchly left the University of Pennsylvania over a dispute about who owned the patents for their invention. They decided to set up their own company. Their first product was the famous UNIVAC computer, the first commercial (that is, mass produced) computer. In the 50’s, UNIVAC (a contraction of “Universal Automatic Computer”) was the household word for “computer” just as “Kleenex” is for “tissue”. The first UNIVAC was sold, appropriately enough, to the Census bureau. UNIVAC was also the first computer to employ magnetic tape.
A microprocessor (uP) is a computer that is fabricated on an integrated circuit (IC). Computers had been around for 20 years before the first microprocessor was developed at Intel in 1971.
1642 – Blaise Pascal invents mechanical calculator (counting device)
1830- Charles’s Babbages “Difference Engine”
First Steam-powered “Analytical Engine”
1880’s- John H. Patterson’s Mechanical cash register (NCR)
First applications for computing devices
1930’s- Claude Shannon: Suggests use of Binary system for use with electronic circuits
1940s- John Von Neumann:Proposes reconfigurable computing by storing programs in memory
1940s – 1950s: First electronic computers,
Vacuum tubes & mechanical relays: UNIVAC, ENIAC
- 30 tons
- 150KWatt
- 80 bytes of memory
ILLIAC (Metze et. al. play Illinois fight song on accumulator bit. – first computer music)
1948- John Bardeen, Walter Brattain, William Schockley file patent on invention of the transistor
1958- Jack Kilby: introduces concept of “Integrated Circuit”
1960s- Computers begin to use transistors.
1965- Gordon Moore
* Observes that every chip produced contained roughly twice as much capacity as its predecessor and that chips new generations of chips were being released every 18-24 months.
Late 1960s- IBM mainframes
- Powerful, centralized CPUs with terminals
- Age of the “big iron”
1970s- DEC PDP-11s
- Low-cost Mini-computers
- Age of the “Vaxen”
1974- Microprocessors
- Intel introduces the 8080 (a “toy”)
- Bill Gates sophmore year at Harvard
1974- Altair 8800
-8080 CPU
-Affordable ($379 kit)
-No screen (LEDs on front panel)
-No keyboard (DIP switches on front panel)
-No storage
-4k memory.
* Bill Gates & Paul Allen start writing BASIC
1977- Apple II, Commodore-64
1980- IBM meets with Bill Gates to license BASIC/MSDOS (QDOS)
1981- IBM Personal Computer:
-16-bit microprocessor: 4.77 MHz 8088
-ROM BASIC,
-cassette interface,
-360k floppy (optional)
-DOS 1.0
1982- Illiac-IV
1983- Low cost computing
-10 MByte Hard disk costs $3000
-640KB of Memory costs $1000
-Compaq introduces “Portable Computing”
1984- Macintosh: GUI based on work at Xerox Parc
-IBM Introduces PC-AT: 80286-based system.
-Record year for IBM.
-Lockwood buys first 8088 computer.
1985- First 32-bit 80×86 CPUs
-Intel introduces 80386
-Address up to 4 Gbytes of memory.
1986- First 32-bit 80×86 Systems
-Compaq introduces first 80386-based system
1989- Intel introduces 80486, includes math co-processor (FPU)
1992- AMD/Cyrix 486 (Compatible CPUs)Intel Pentium (64-bit memory bus)
1996- Use of Reduced Instruction Set Computer (RISC) core to exectute 80×86 instructions
-AMD K5 (RISC Ops = ROPS)
-Intel Pentium Pro
-Superscalar Execution
-AMD K5/K6
-Cyrix M1 (6×86)
-Intel Pentium Pro
*Powerful, Entry-level systems
-100 MIP CPUs
-32M DRAM
-12x CDROM
1997- Single Instruction Multiple Data (SIMD):Multimedia Extensions / Matrix Math Extensions (MMX)
-AMD K6,
-Intel Pentium-II
-Cyrix/IBM M2 (6×86 MX)
*Low-Cost computing:
-233 Mhz CPU w/MMX: $300
-64MB of Memory: $300 (300 times cheaper/MB than 1983 !)
1998- Single Instruction Multiple Data (SIMD) for Floating Point operations
-AMD K6-2 w/3DNow
*Integrated CPU/Video/Audio:
-Cyrix/NSM MediaGX
*Low-Cost computing:
-300 MHz CPU w/MMX+3D: $125
-64 MB of Memory (PC-100 SDRAM): $75
-10 GByte Hard Drive: $200
1999+- More Floating point Parallelism
-Pentium III (Katmai)
* Faster Bus Architectures
-AMD K3-III (3DNow + 256k on-chip Full-speed L2 cache)
-AMD K7 (Fast Alpha EV-6 Bus)
* Explicit Instruction-level Floating-point Parallelism:
-Merced IA-64 (80×86/PA-RISC)
-Supercomputing on the Microprocessor
-Ubiquitous Computing
-Active Networks
Computer Generations
1-First Generation Computers
First generation computers used Thermion valves. These computers were large in size and writing programs on them was difficult.
Some of the computers of this generation were:
ENIAC : It was named Electronic Numerical Integrator And Calculator (ENIAC). Today your favorite computer is many times as powerful as ENIAC, still size is very small.
EDVAC: It stands for Electronic Discrete Variable Automatic Computer and was developed in 1950. The advantages is storing and doing logical decision internally.
- Other Important Computers of First Generation:
EDSAC: ( Electronic Delay Storage Automatic Computer )
UNIVAC-1.
1977- Apple II, Commodore-64
1980- IBM meets with Bill Gates to license BASIC/MSDOS (QDOS)
1981- IBM Personal Computer:
-16-bit microprocessor: 4.77 MHz 8088
-ROM BASIC,
-cassette interface,
-360k floppy (optional)
-DOS 1.0
1982- Illiac-IV
1983- Low cost computing
-10 MByte Hard disk costs $3000
-640KB of Memory costs $1000
-Compaq introduces “Portable Computing”
1984- Macintosh: GUI based on work at Xerox Parc
-IBM Introduces PC-AT: 80286-based system.
-Record year for IBM.
-Lockwood buys first 8088 computer.
1985- First 32-bit 80×86 CPUs
-Intel introduces 80386
-Address up to 4 Gbytes of memory.
1986- First 32-bit 80×86 Systems
-Compaq introduces first 80386-based system
1989- Intel introduces 80486, includes math co-processor (FPU)
1992- AMD/Cyrix 486 (Compatible CPUs)Intel Pentium (64-bit memory bus)
1996- Use of Reduced Instruction Set Computer (RISC) core to exectute 80×86 instructions
-AMD K5 (RISC Ops = ROPS)
-Intel Pentium Pro
-Superscalar Execution
-AMD K5/K6
-Cyrix M1 (6×86)
-Intel Pentium Pro
*Powerful, Entry-level systems
-100 MIP CPUs
-32M DRAM
-12x CDROM
1997- Single Instruction Multiple Data (SIMD):Multimedia Extensions / Matrix Math Extensions (MMX)
-AMD K6,
-Intel Pentium-II
-Cyrix/IBM M2 (6×86 MX)
*Low-Cost computing:
-233 Mhz CPU w/MMX: $300
-64MB of Memory: $300 (300 times cheaper/MB than 1983 !)
1998- Single Instruction Multiple Data (SIMD) for Floating Point operations
-AMD K6-2 w/3DNow
*Integrated CPU/Video/Audio:
-Cyrix/NSM MediaGX
*Low-Cost computing:
-300 MHz CPU w/MMX+3D: $125
-64 MB of Memory (PC-100 SDRAM): $75
-10 GByte Hard Drive: $200
1999+- More Floating point Parallelism
-Pentium III (Katmai)
* Faster Bus Architectures
-AMD K3-III (3DNow + 256k on-chip Full-speed L2 cache)
-AMD K7 (Fast Alpha EV-6 Bus)
* Explicit Instruction-level Floating-point Parallelism:
-Merced IA-64 (80×86/PA-RISC)
-Supercomputing on the Microprocessor
-Ubiquitous Computing
-Active Networks
Computer Generations
1-First Generation Computers
First generation computers used Thermion valves. These computers were large in size and writing programs on them was difficult.
Some of the computers of this generation were:
ENIAC : It was named Electronic Numerical Integrator And Calculator (ENIAC). Today your favorite computer is many times as powerful as ENIAC, still size is very small.
EDVAC: It stands for Electronic Discrete Variable Automatic Computer and was developed in 1950. The advantages is storing and doing logical decision internally.
- Other Important Computers of First Generation:
EDSAC: ( Electronic Delay Storage Automatic Computer )
UNIVAC-1.
Limitations of First Generation Computer:
· The operating speed was quite slow.
· Power consumption was very high.
· It required large space for installation.
· The programming capability was quite low.
2-Second Generation Computers
*Around 1955 a device called Transistor replaced the bulky electric tubes in the first generation computer. They have no filament and require no heating. Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.
*It is in the second generation that the concept of Central Processing Unit (CPU), memory, programming language and input and output units were developed. The programming languages such as COBOL, FORTRAN were developed during this period. Some of the computers of the Second Generation were:
*IBM 1620: Its size was smaller as compared to First Generation computers and mostly used for scientific purpose.
*IBM 1401: Its size was small to medium and used for business applications.
*CDC 3600: Its size was large and is used for scientific purposes.
3 Third Generation Computers
was introduced in 1964. They used Integrated Circuits (ICs). Some of the computers developed during this period were: IBM-360, ICL-1900, IBM-370, and VAX-750.
*Higher level language such as BASIC was developed during this period.
*Computers of this generations were small in size, low cost, large memory and processing speed is very high.
4-Fourth Generation Computers( present day computers) .
It uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer’s central processing unit (CPU) on single chip. These computers are called microcomputers.
5-Fifth Generation Computer
was introduced in 1990s . The speed is extremely high and it can perform parallel processing. The concept of Artificial intelligence has been introduced to allow the computer to take its own decision. It is still in a developmental stage.
Classification of Computers
Analog computer:
Digital computer:
1-Microcomputer.
Microcomputer is at the lowest end of the computer range in terms of speed and storage capacity. Its CPU is a microprocessor. The most common application of personal computers (PC) is in this category. The PC supports a number of input and output devices. Examples of microcomputer are IBM PC, PC-AT
-1973: Xerox Alto
-1975: Altair
-1978: Apple II
-1981: IBM PC (5150)
-1983: Apple Macintosh
2-Mini Computer.
-The mini computer is used in multi-user system in which various users can work at the same time. This type of computer is generally used for processing large volume of data in an organization. They are also used as servers in Local Area Networks (LAN).
3-Mainframes.
-These types of computers are generally 32-bit microprocessors. They operate at very high speed, have very large storage capacity and can handle the work load of many users. They are generally used in centralized databases. They are also used as controlling nodes in Wide Area Networks (WAN).
-Example of mainframes are DEC, ICL and IBM 3000 series.
4-Supercomputer.
They are the fastest and most expensive machines. They have high processing speed compared to other computers. They have also multiprocessing technique. One of the ways in which supercomputers are built is by interconnecting hundreds of microprocessors.
-Supercomputers are mainly being used for whether forecasting, biomedical research, remote sensing, aircraft design and other areas of science and technology. Examples of supercomputers are CRAY YMP, CRAY2, NEC SX-3, CRAY XMP and PARAM from India.
Categories of Computers
Rapid advances in computer technology often blur the differences among types of computers, and industry professionals may disagree on how computers should be categorized. Typically, they use criteria based on differences in usage, size, speed, processing capabilities, and price, resulting in the following categories. For an overview, see Table 1-1.
Personal Computers
A personal computer (PC) is a self-contained computer capable of input, processing, output, and storage. A personal computer is designed to be a single-user computer and must have at least one input device, one output device, a processor, and memory. The three major groups of PCs are desktop computers, portable computers, and handheld computers.
Desktop Computers A desktop computer is a PC designed to allow the system unit, input devices, output devices, and other connected devices to fit on top of, beside, or under a user’s desk or table. This type of computer may be used in the home, a home office, a library, or a corporate setting.
Portable Computers A portable computer is a PC small enough to be moved around easily. As the name suggests, a laptop computer fits comfortably on the lap. As laptop computers have decreased in size, this type of computer is now more commonly referred to as a notebook computer. Manufacturers recently began introducing a new type of computer called the tablet PC, which has a liquid crystal display (LCD) screen on which the user can write using a special-purpose pen, or stylus. Tablet PCs rely on digital ink technology that allows the user to write on the screen. Another type of portable computer, called a wearable computer, is worn somewhere on the body, thereby providing a user with access to mobile computing capabilities and information via the Internet.
Did You Know? In 1974, Micro Instrumentation Telemetry Systems (MITS) began selling the Altair personal computer, widely regarded as the world’s first PC, as a mail-order kit. Buyers were required to assemble the components.
Handheld Computers An even smaller type of personal computer that can fit into the hand is known as a handheld computer (also called simply handheld, pocket PC, or Palmtop). In recent years, a type of handheld computer called a personal digital assistant (PDA) has become widely used for performing calculations, keeping track of schedules, making appointments, and writing memos. Some handheld computers are Internet-enabled, meaning they can access the Internet without wire connections. For example, a smartphone is a cell phone that connects to the Internet to allow users to transmit and receive e-mail messages, send text messages and pictures, and browse through Web sites on the phone display screen.
Workstations
A workstation is a high-performance single-user computer with advanced input, output, and storage components that can be networked with other workstations and larger computers. Workstations are typically used for complex applications that require considerable computing power and high-quality graphics resolution, such as computer-aided design (CAD), computer-assisted manufacturing (CAM), desktop publishing, and software development.
· The operating speed was quite slow.
· Power consumption was very high.
· It required large space for installation.
· The programming capability was quite low.
2-Second Generation Computers
*Around 1955 a device called Transistor replaced the bulky electric tubes in the first generation computer. They have no filament and require no heating. Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.
*It is in the second generation that the concept of Central Processing Unit (CPU), memory, programming language and input and output units were developed. The programming languages such as COBOL, FORTRAN were developed during this period. Some of the computers of the Second Generation were:
*IBM 1620: Its size was smaller as compared to First Generation computers and mostly used for scientific purpose.
*IBM 1401: Its size was small to medium and used for business applications.
*CDC 3600: Its size was large and is used for scientific purposes.
3 Third Generation Computers
was introduced in 1964. They used Integrated Circuits (ICs). Some of the computers developed during this period were: IBM-360, ICL-1900, IBM-370, and VAX-750.
*Higher level language such as BASIC was developed during this period.
*Computers of this generations were small in size, low cost, large memory and processing speed is very high.
4-Fourth Generation Computers( present day computers) .
It uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer’s central processing unit (CPU) on single chip. These computers are called microcomputers.
5-Fifth Generation Computer
was introduced in 1990s . The speed is extremely high and it can perform parallel processing. The concept of Artificial intelligence has been introduced to allow the computer to take its own decision. It is still in a developmental stage.
Classification of Computers
Analog computer:
Digital computer:
1-Microcomputer.
Microcomputer is at the lowest end of the computer range in terms of speed and storage capacity. Its CPU is a microprocessor. The most common application of personal computers (PC) is in this category. The PC supports a number of input and output devices. Examples of microcomputer are IBM PC, PC-AT
-1973: Xerox Alto
-1975: Altair
-1978: Apple II
-1981: IBM PC (5150)
-1983: Apple Macintosh
2-Mini Computer.
-The mini computer is used in multi-user system in which various users can work at the same time. This type of computer is generally used for processing large volume of data in an organization. They are also used as servers in Local Area Networks (LAN).
3-Mainframes.
-These types of computers are generally 32-bit microprocessors. They operate at very high speed, have very large storage capacity and can handle the work load of many users. They are generally used in centralized databases. They are also used as controlling nodes in Wide Area Networks (WAN).
-Example of mainframes are DEC, ICL and IBM 3000 series.
4-Supercomputer.
They are the fastest and most expensive machines. They have high processing speed compared to other computers. They have also multiprocessing technique. One of the ways in which supercomputers are built is by interconnecting hundreds of microprocessors.
-Supercomputers are mainly being used for whether forecasting, biomedical research, remote sensing, aircraft design and other areas of science and technology. Examples of supercomputers are CRAY YMP, CRAY2, NEC SX-3, CRAY XMP and PARAM from India.
Categories of Computers
Rapid advances in computer technology often blur the differences among types of computers, and industry professionals may disagree on how computers should be categorized. Typically, they use criteria based on differences in usage, size, speed, processing capabilities, and price, resulting in the following categories. For an overview, see Table 1-1.
Personal Computers
A personal computer (PC) is a self-contained computer capable of input, processing, output, and storage. A personal computer is designed to be a single-user computer and must have at least one input device, one output device, a processor, and memory. The three major groups of PCs are desktop computers, portable computers, and handheld computers.
Desktop Computers A desktop computer is a PC designed to allow the system unit, input devices, output devices, and other connected devices to fit on top of, beside, or under a user’s desk or table. This type of computer may be used in the home, a home office, a library, or a corporate setting.
Portable Computers A portable computer is a PC small enough to be moved around easily. As the name suggests, a laptop computer fits comfortably on the lap. As laptop computers have decreased in size, this type of computer is now more commonly referred to as a notebook computer. Manufacturers recently began introducing a new type of computer called the tablet PC, which has a liquid crystal display (LCD) screen on which the user can write using a special-purpose pen, or stylus. Tablet PCs rely on digital ink technology that allows the user to write on the screen. Another type of portable computer, called a wearable computer, is worn somewhere on the body, thereby providing a user with access to mobile computing capabilities and information via the Internet.
Did You Know? In 1974, Micro Instrumentation Telemetry Systems (MITS) began selling the Altair personal computer, widely regarded as the world’s first PC, as a mail-order kit. Buyers were required to assemble the components.
Handheld Computers An even smaller type of personal computer that can fit into the hand is known as a handheld computer (also called simply handheld, pocket PC, or Palmtop). In recent years, a type of handheld computer called a personal digital assistant (PDA) has become widely used for performing calculations, keeping track of schedules, making appointments, and writing memos. Some handheld computers are Internet-enabled, meaning they can access the Internet without wire connections. For example, a smartphone is a cell phone that connects to the Internet to allow users to transmit and receive e-mail messages, send text messages and pictures, and browse through Web sites on the phone display screen.
Workstations
A workstation is a high-performance single-user computer with advanced input, output, and storage components that can be networked with other workstations and larger computers. Workstations are typically used for complex applications that require considerable computing power and high-quality graphics resolution, such as computer-aided design (CAD), computer-assisted manufacturing (CAM), desktop publishing, and software development.
Midrange Servers
Linked computers and terminals are typically connected to a larger and more powerful computer called a network server, sometimes referred to as a host computer. Although the size and capacity of network servers vary considerably, most are midrange rather than large mainframe computers (discussed later).
Ø Midrange server – formerly known as a minicomputer, a midrange server is a powerful computer capable of accommodating hundreds of client computers or terminals (users) at the same time.
Ø Terminal – a device consisting of only a monitor and keyboard, with no processing capability of its own.
Mainframe Computers
Larger, more powerful, and more expensive than midrange servers, a mainframe computer is capable of accommodating hundreds of network users performing different computing tasks. These computers are useful for dealing with large, ever-changing collections of data that can be accessed by many users simultaneously. Government agencies, banks, universities, and insurance companies use mainframes to handle millions of transactions each day.
Supercomputers
A supercomputer is the fastest, most powerful, and most expensive of all computers. Many are capable of performing trillions of calculations in a single second. Primary applications include weather forecasting, comparing DNA sequences, creating artificially intelligent robots, and performing financial analyses.
Did You Know? The fastest computer in the world is IBM’s latest supercomputer, named the BlueGene/L. Housed at the Lawrence Livermore National Laboratory, it can perform up to 280.6 trillion calculations in one second. The next system, Blue Gene/P, scheduled for completion in 2008, is expected to have a processing speed of 1 quadrillion calculations per second.
Linked computers and terminals are typically connected to a larger and more powerful computer called a network server, sometimes referred to as a host computer. Although the size and capacity of network servers vary considerably, most are midrange rather than large mainframe computers (discussed later).
Ø Midrange server – formerly known as a minicomputer, a midrange server is a powerful computer capable of accommodating hundreds of client computers or terminals (users) at the same time.
Ø Terminal – a device consisting of only a monitor and keyboard, with no processing capability of its own.
Mainframe Computers
Larger, more powerful, and more expensive than midrange servers, a mainframe computer is capable of accommodating hundreds of network users performing different computing tasks. These computers are useful for dealing with large, ever-changing collections of data that can be accessed by many users simultaneously. Government agencies, banks, universities, and insurance companies use mainframes to handle millions of transactions each day.
Supercomputers
A supercomputer is the fastest, most powerful, and most expensive of all computers. Many are capable of performing trillions of calculations in a single second. Primary applications include weather forecasting, comparing DNA sequences, creating artificially intelligent robots, and performing financial analyses.
Did You Know? The fastest computer in the world is IBM’s latest supercomputer, named the BlueGene/L. Housed at the Lawrence Livermore National Laboratory, it can perform up to 280.6 trillion calculations in one second. The next system, Blue Gene/P, scheduled for completion in 2008, is expected to have a processing speed of 1 quadrillion calculations per second.
Computer Hardware: An Overview
Hardware includes all of the physical components that comprise the computer and other devices connected to it, such as the keyboard or monitor. These connected devices are referred to as peripheral devices because they are outside, or peripheral to, the computer.
Hardware devices are grouped into the following categories:
-system unit
-input devices
-output devices
-storage devices
-communications devices
The System Unit The system unit is a relatively small plastic or metal cabinet housing the electronic components that process data into information. Inside the cabinet is the main circuit board, called the motherboard (Figure 1-7), which provides for the installation and connection of other electronic components. The main components of the motherboard include:
*central processing unit (CPU), also called the processor, which consists of electronic chips that read, interpret, and execute the instructions that operate the computer and perform specific computing tasks.
*memory, also called primary storage, which consists of small electronic chips that provide temporary storage for instructions and data during processing.
Input Devices An input device is a hardware device that allows users to enter program instructions, data, and commands into a computer. Common input devices are the keyboard, mouse, and microphone.
Output Devices An output device is a device that makes information available to the user. Some output devices produce output in hardcopy (tangible) form, while other output devices produce output in softcopy (intangible) form that can be viewed, but not physically handled.
Storage Devices Unlike memory that stores instructions and data temporarily during processing, a storage device, often called secondary storage, provides for the permanent storage of programs, data, and information that can be reused.
Communications Devices A communications device makes it possible for a user to communicate with another computer and to exchange instructions, data, and information with other computer users. The most popular communications device is a modem, an electronic device capable of converting computer-readable information into a form that communications systems, such as standard telephone lines, can transmit and receive.
The Central Processing Unit
Every computer contains a central processing unit (CPU). The CPU of larger computers often spans several separate microprocessor chips and various circuit boards, whereas in a personal computer the CPU is a single chip. This microprocessor chip is a small electronic device consisting of tiny transistors and other circuit parts on a piece of semiconductor material.
Recall from Chapter 1 that the CPU, or microprocessor, is often referred to as the “brain” of a personal computer system because it interprets and executes the instructions for most computer operations. The CPU consists of a control unit, an arithmetic/logic unit (ALU), and registers (see Figure 2-13).
These components of the CPU perform four basic operations that are collectively called a machine cycle. The machine cycle includes fetching an instruction, decoding the instruction, executing the instruction, and storing the result (see Figure 2-14). The machine cycle is the same for all types of computers.
Did You Know? Intel’s first microprocessor, the 4004, was introduced in 1971. It contained 2,300 transistors. Today’s Pentium 4 processor, by contrast, contains 55 million transistors.
Control Unit The control unit directs and coordinates the overall operation of the computer system. It acts as a traffic officer, signaling to other parts of the computer system what they are to do. It interprets program instructions and then initiates the action needed to carry them out. These are the fetching and decoding steps of the machine cycle. Fetching means retrieving an instruction or data from memory. Decoding means interpreting or translating the instruction into strings of binary digits (bytes) the computer understands. The time required to fetch and decode an instruction is called instruction time, or I-time.
Arithmetic/Logic Unit The arithmetic/logic unit (ALU) is the part of the CPU that performs the executing step of the machine cycle. Executing means carrying out the instructions and performing arithmetic and logical operations on the data. The arithmetic operations the ALU can perform are addition, subtraction, multiplication, and division. The ALU can also perform logical operations, such as comparing data items.
Registers To speed up processing, the ALU uses registers (temporary storage locations) to hold instructions and data. This is the storing step of the machine cycle. Storing means writing or recording the result to memory. The time required to execute and store an instruction is called execution time, or E-time.
Various kinds of registers are used, each serving a specific purpose. Once processing begins, an instruction register holds instructions currently being executed. A data register holds the data items being acted upon. A storage register hold the immediate and final results of processing.
Number Systems
Binary to Decimal
• Technique
– Multiply each bit by 2n, where n is the “weight” of the bit
– The weight is the position of the bit, starting from 0 on the right
– Add the results
1010112 => 1 x 20 = 1
Hardware includes all of the physical components that comprise the computer and other devices connected to it, such as the keyboard or monitor. These connected devices are referred to as peripheral devices because they are outside, or peripheral to, the computer.
Hardware devices are grouped into the following categories:
-system unit
-input devices
-output devices
-storage devices
-communications devices
The System Unit The system unit is a relatively small plastic or metal cabinet housing the electronic components that process data into information. Inside the cabinet is the main circuit board, called the motherboard (Figure 1-7), which provides for the installation and connection of other electronic components. The main components of the motherboard include:
*central processing unit (CPU), also called the processor, which consists of electronic chips that read, interpret, and execute the instructions that operate the computer and perform specific computing tasks.
*memory, also called primary storage, which consists of small electronic chips that provide temporary storage for instructions and data during processing.
Input Devices An input device is a hardware device that allows users to enter program instructions, data, and commands into a computer. Common input devices are the keyboard, mouse, and microphone.
Output Devices An output device is a device that makes information available to the user. Some output devices produce output in hardcopy (tangible) form, while other output devices produce output in softcopy (intangible) form that can be viewed, but not physically handled.
Storage Devices Unlike memory that stores instructions and data temporarily during processing, a storage device, often called secondary storage, provides for the permanent storage of programs, data, and information that can be reused.
Communications Devices A communications device makes it possible for a user to communicate with another computer and to exchange instructions, data, and information with other computer users. The most popular communications device is a modem, an electronic device capable of converting computer-readable information into a form that communications systems, such as standard telephone lines, can transmit and receive.
The Central Processing Unit
Every computer contains a central processing unit (CPU). The CPU of larger computers often spans several separate microprocessor chips and various circuit boards, whereas in a personal computer the CPU is a single chip. This microprocessor chip is a small electronic device consisting of tiny transistors and other circuit parts on a piece of semiconductor material.
Recall from Chapter 1 that the CPU, or microprocessor, is often referred to as the “brain” of a personal computer system because it interprets and executes the instructions for most computer operations. The CPU consists of a control unit, an arithmetic/logic unit (ALU), and registers (see Figure 2-13).
These components of the CPU perform four basic operations that are collectively called a machine cycle. The machine cycle includes fetching an instruction, decoding the instruction, executing the instruction, and storing the result (see Figure 2-14). The machine cycle is the same for all types of computers.
Did You Know? Intel’s first microprocessor, the 4004, was introduced in 1971. It contained 2,300 transistors. Today’s Pentium 4 processor, by contrast, contains 55 million transistors.
Control Unit The control unit directs and coordinates the overall operation of the computer system. It acts as a traffic officer, signaling to other parts of the computer system what they are to do. It interprets program instructions and then initiates the action needed to carry them out. These are the fetching and decoding steps of the machine cycle. Fetching means retrieving an instruction or data from memory. Decoding means interpreting or translating the instruction into strings of binary digits (bytes) the computer understands. The time required to fetch and decode an instruction is called instruction time, or I-time.
Arithmetic/Logic Unit The arithmetic/logic unit (ALU) is the part of the CPU that performs the executing step of the machine cycle. Executing means carrying out the instructions and performing arithmetic and logical operations on the data. The arithmetic operations the ALU can perform are addition, subtraction, multiplication, and division. The ALU can also perform logical operations, such as comparing data items.
Registers To speed up processing, the ALU uses registers (temporary storage locations) to hold instructions and data. This is the storing step of the machine cycle. Storing means writing or recording the result to memory. The time required to execute and store an instruction is called execution time, or E-time.
Various kinds of registers are used, each serving a specific purpose. Once processing begins, an instruction register holds instructions currently being executed. A data register holds the data items being acted upon. A storage register hold the immediate and final results of processing.
Number Systems
Binary to Decimal
• Technique
– Multiply each bit by 2n, where n is the “weight” of the bit
– The weight is the position of the bit, starting from 0 on the right
– Add the results
1010112 => 1 x 20 = 1
1 x 21 = 2
0 x 22 = 0
1 x 23 = 8
0 x 24 = 0
1 x 25 =32
4310
Octal to Decimal
Technique
– Multiply each bit by 8n, where n is the “weight” of the bit
– The weight is the position of the bit, starting from 0 on the right
– Add the results
7248 => 4 x 80 = 4
4310
Octal to Decimal
Technique
– Multiply each bit by 8n, where n is the “weight” of the bit
– The weight is the position of the bit, starting from 0 on the right
– Add the results
7248 => 4 x 80 = 4
2 x 81 = 16
7 x 82 = 448
46810
Hexadecimal to Decimal
Technique
– Multiply each bit by 16n, where n is the “weight” of the bit
– The weight is the position of the bit, starting from 0 on the right
– Add the results
ABC16 => C x 160 = 12 x 1 = 12
Hexadecimal to Decimal
Technique
– Multiply each bit by 16n, where n is the “weight” of the bit
– The weight is the position of the bit, starting from 0 on the right
– Add the results
ABC16 => C x 160 = 12 x 1 = 12
B x 161 = 11 x 16 = 176
A x 162 = 10 x 256 = 2560
274810
Decimal to Binary
• Technique
– Divide by two, keep track of the remainder
– First remainder is bit 0 (LSB, least-significant bit)
– Second remainder is bit 1
– Etc.
12510 =? 2
12510 = 11111012
Octal to Binary
• Technique
– Convert each octal digit to a 3-bit equivalent binary representation
Hexadecimal to Binary
• Technique
– Convert each hexadecimal digit to a 4-bit equivalent binary representation
• Convert a hexadecimal number to a binary number,
• simply divided the binary number into 4-bit groups
• Substitute the corresponding four bits in binary for each hexadecimal digit in the number.
• For example, convert ABCD to a binary value, The binary equivalent is:
• ABCD= 1010 1011 1100 1101
Binary to Octal
• Technique
– Group bits in threes, starting on right
– Convert to octal digits
Binary to Hexadecimal
• Technique
– Group bits in fours, starting on right
– Convert to hexadecimal digits
• Binary to Hex Conversion
• Break the binary number into 4-bit groups from the Left to the right.
• Convert the 4-bit binary number to its Hex equivalent.
• For example, the binary value 101011111011 0010 will be written:
• 1010 1111 1011 0010=AFB2
274810
Decimal to Binary
• Technique
– Divide by two, keep track of the remainder
– First remainder is bit 0 (LSB, least-significant bit)
– Second remainder is bit 1
– Etc.
12510 =? 2
12510 = 11111012
Octal to Binary
• Technique
– Convert each octal digit to a 3-bit equivalent binary representation
Hexadecimal to Binary
• Technique
– Convert each hexadecimal digit to a 4-bit equivalent binary representation
• Convert a hexadecimal number to a binary number,
• simply divided the binary number into 4-bit groups
• Substitute the corresponding four bits in binary for each hexadecimal digit in the number.
• For example, convert ABCD to a binary value, The binary equivalent is:
• ABCD= 1010 1011 1100 1101
Binary to Octal
• Technique
– Group bits in threes, starting on right
– Convert to octal digits
Binary to Hexadecimal
• Technique
– Group bits in fours, starting on right
– Convert to hexadecimal digits
• Binary to Hex Conversion
• Break the binary number into 4-bit groups from the Left to the right.
• Convert the 4-bit binary number to its Hex equivalent.
• For example, the binary value 101011111011 0010 will be written:
• 1010 1111 1011 0010=AFB2
Computer Softwares
Hardware
$ Hardware is the machine itself and its various individual equipment.
$ It includes all mechanical,electronic and magnetic devices such as monitor, printer, electronic circuit, floppy and hard disk.
Software
· Software refers to the set of computer programs, which are used in applications and operating systems.
· It is the collection of programs, which increase the capabilities of the hardware.
· Software guides the computer at every step where to start and stop during a particular job. · The process of software development is called programming.
SOFTWARE TYPES
Application Software:
· Application Software is a set of programs for a specific application.
· Application software is useful for word processing, accounting, producing statistical report, Graphics, Excel and Data Base.
· programming languages COBOL, FORTRAN, C++, VB, VC, Java
Types of Application Software
Application software enables users to perform the activities and work that computers were designed for. The specific type of application used depends on the intended purpose, and there are application programs for almost every need. Three broad types of application software available for business users are individual, collaboration, and vertical programs (see Table 5-1).
Individual application software refers to programs individuals use at work or at home. Examples include word processing, spreadsheet, database management, and desktop publishing programs.
Collaboration software (also called groupware) enables people at separate PC workstations to work together on a single document or project, such as designing a new automobile engine.
Vertical application software is a complete package of programs that work together to perform core business functions for a large organization. For example, a bank might have a mainframe computer at its corporate headquarters connected to conventional terminals in branch offices, where they are used by managers, tellers, loan officers, and other employees. All financial transactions are fed to the central computer for processing. The system then generates managers’ reports, account statements, and other essential documents.
Other Application Software Models
Shareware Shareware is software developed by an individual or software publisher who retains ownership of the product and makes it available for a small “contribution” fee. The voluntary fee normally entitles users to receive online or written product documentation and technical help.
Freeware Freeware is software that is provided free of charge to anyone wanting to use it. Hundreds of freeware programs are available, many written by college students and professors who create programs as class projects or as part of their research.
Open Source Software An open source software program is software whose programming code is owned by the original developer but made available free to the general public, who is encouraged to experiment with the software, make improvements, and share the improvements with the user community
Application Software for Individual Use
The thousands of application programs that individuals use to perform computing tasks at work and at home can be grouped into four types:
$ productivity software
$ software for household use
$ graphics and multimedia software
$ communication software
Productivity Software
Productivity software is designed to improve efficiency and performance on the job and at home, and is the largest category of application software for individual use. In-depth knowledge and skill in using productivity software applications can make a potential employee more valuable to a business, organization, or agency.
Word Processing
A word processing program can be used to create almost any kind of printed document. Word processors are the most widely used of all software applications because they are central to communication. Whatever the type of document created with a word processing program, the essential parts of the procedure remain the same:
$create (enter) text
$edit the text
$format the document
$save and print the file
Desktop Publishing
Desktop publishing (DTP) software allows users to create impressive documents that include text, drawings, photographs, and various graphics elements in full color. Professional-quality publications can be produced with DTP software. Textbooks such as this one may be designed and laid out with a desktop publishing application such as PageMaker, QuarkXpress, or Adobe InDesign. Major word processors offer limited desktop publishing features sufficient for creating simple newsletters and brochures.
Spreadsheets
Spreadsheet software is an electronic version of the ruled worksheets accountants used in the past. Spreadsheet software provides a means of organizing, calculating, and presenting financial, statistical, and other numerical information. Businesses find spreadsheets particularly useful for evaluating alternative scenarios. The spreadsheet uses “what if” calculations to evaluate possibilities. By entering various data values and formulas into a spreadsheet, questions can be answered quickly and accurately.
For the individual user, spreadsheets fulfill many purposes, including:
$ preparing and analyzing personal or business budgets
$ reconciling checkbooks
$ analyzing financial situations
$ tracking and analyzing investments
$ preparing personal financial statements
$ estimating taxes
Database Management
In a computerized database system, data are stored in electronic form on a storage medium, such as hard or floppy disks or CDs. A database is a collection of data organized in one or more tables consisting of individual pieces of information, each located in a field, and a collection of related fields, each collection making up one record (see Figure 5-1). A commercial database program typically allows users to create a form for entering data. A user can design an electronic form to make entering information into the database easier. The information entered using such a form will become a record in a table. Users can add, remove, or change the stored data.
Presentation Graphics
Presentation graphics software allows users to create computerized slide shows that combine text, numbers, animation, graphics, sounds, and videos. A slide is an individual document that is created in presentation graphics software. A slide show may consist of any number of individual slides. For example, an instructor may use a slide show to accompany a lecture to make it more engaging and informative. Microsoft PowerPoint and Corel Presentations are two popular presentation software programs.
Software for Household Use
Numerous software applications designed for use in the household are available for purchase. Among the many products available are applications for managing personal finances, preparing tax returns, preparing legal documents, playing games, and education and reference.
Graphics and Multimedia Software
Graphics and multimedia software allows both professional and home users to work with graphics, video, and audio. A variety of applications software is focused in this area, including painting and drawing software, image-editing software, video and audio editing software, Web authoring software, and computer-aided design (CAD) software.
Communications Software
One of the major reasons people use computers is to communicate with others and to retrieve and share information. Communications software allows users to send and receive e-mail, browse and search the Web, engage in group communications and discussions, and participate in videoconferencing activities.
Automatic Multimedia Tagging Software
Advances in Speech Recognition Software
Pattern Recognition Software
Distributed Computing
System Software:
· When you switch on the computer the programs written in ROM is executed which activates different units of your computer and makes it ready for you to work.
· This set of programs can be called system software.
· System software are general programs designed for performing tasks such as controlling all operations required to move data into and out of the computer
· System Software allows application packages to be run on the computer.
Computer manufactures build and supply this system software with the computer system.
An operating system is the most important piece of software on a personal computer. The location of the operating system identifies the boot drive for the personal computer, which is typically the hard drive. Once started, the operating system manages the computer system and performs functions related to the input, processing, output, and storage of information, including:
managing main memory, or RAM
$ configuring and controlling peripheral devices
$ managing essential file operations, including formatting or copying disks, and renaming or deleting files
$ monitoring system performance
$ providing a user interface
Windows
Windows 2000 Professional Windows 2000 Professional, introduced in late 1999, was designed for use with business computers and was the successor to Windows 98 for office environments. Incorporating the power of Windows NT, Windows 2000 Professional was used to link
Windows XP Professional Microsoft’s Windows XP Professional was designed for the latest computers that are fast, powerful, and have lots of memory and hard disk space. It combined the more powerful features of Windows 2000 and Windows NT and included many cosmetic changes. Windows XP contained many new and improved features and was extremely user-friendly. Icons had a three-dimensional look, and provided impressive features for managing photo and music files. It was the first Windows version to be copy-protected.
Windows Vista Windows Vista, released in 2007, improves and expands on Windows XP’s capabilities. It provides much more robust security features than any earlier version. The centerpiece of this security system is User Access Control (UAC), a protection system that prompts the user for administrator-level credentials whenever an operation is attempted that might affect system stability or security in some way. Home networking is easier than ever with Windows Vista.
Macintosh Operating System
The Macintosh, the first commercial GUI, was originally released in 1984 and has been updated many times since. It included a virtual desktop, pull-down menus, dialog boxes, and icons representing common commands and programs. With its impressive graphics and ease of use, it quickly became the model for other GUIs.
OS/2
IBM’s OS/2 GUI operating system was the company’s response to the popularity of Microsoft Windows and the Apple Mac OS. The latest version is called OS/2 Warp. In addition to running native application programs, OS/2 can also run programs written for DOS and Windows systems.
Linux
Linux is a UNIX-based operating system that runs on a number of computer platforms including PCs, servers, and handheld devices. The Linux kernel (the central module or basic part) was developed mainly by Linus Torvalds. Torvalds designed Linux as an open-source software program, which means that the developer retains ownership of the original programming code but makes it free to the general public, who is encouraged to experiment with the software, make improvements, and share the improvements with the entire user community. During recent years, many improvements and refinements have been made rendering Linux an extremely popular and functional operating system for both large and small computers.
Server Operating Systems
Some operating systems are designed specifically for use with local area networks, allowing multiple users to connect to the server and to share network resources such as files and peripheral devices such as printers. The kind of operating system selected for use with a network server depends on network architecture and processing requirements.
Novell Netware
NetWare, developed by Novell, Inc. during the 1980s, is a popular and widely used operating system for microcomputer-based local area networks. Network users have the option of working with or without network resources.
Windows
Microsoft’s Windows NT Server was one of Microsoft’s earlier entries into the client/server market. It supported the connection of various peripheral devices and multitasking operations in which networked computers could process applications at the same time. Windows NT Server was replaced by Windows 2000 Server.
UNIX
Developed in the early 1970s by programmers at Bell Laboratories, the UNIX operating system was originally designed for servers and large computer systems
Linux Linux (pronounced LIN-UKS) is one of the fastest-growing server operating systems. Linux is an open-source software program based on the UNIX operating system
Solaris Solaris is a Unix-based operating environment developed by Sun Microsystems. It was originally developed to run on Sun’s SPARC workstations but now runs on many workstations from other manufacturers
Compiler :It is a program translator that translates the instruction of a higher level language to machine language.
An interpreter is another type of program translator used for translating higher level language into machine language.
1 . It takes one statement of higher level languages, translate it into machine language and immediately execute it.
Software Development Steps
Software Development Life Cycle
The product developed which achieves customer satisfaction is not done in a single step. It involves series of steps in a software development process. This is needed to develop quality products with error free products to achieve customer satisfaction. There are many models available in the software development process.
But majority of software development process follow the model named as software development life cycle. This software develop life cycle has number of steps in it. The below article describes about the software development life cycle and the steps involved into it.
Software development life cycle model is also called as waterfall model which is followed by majority of systems. This software development life cycle process has the following seven stages in it namely
1. System Requirements Analysis2. Feasibility study3. Systems Analysis and Design4. Code Generation5. Testing6. Maintenance7. Implementation
Let us discuss each of these to have an overview about teach of the following steps in software development life cycle.
1. System Requirements Analysis:
The first essential or vital thing required for any software development is system. Also the system requirement may vary based on the software product that is going to get developed. So a careful analysis has to be made about the system requirement needed for the development of the product. After the analysis and design of the system requirement phase the system required for the development would be complete and the concentration can be on the software development process.
2. Feasibility study:
After making an analysis in the system requirement the next step is to make analysis of the software requirement. In other words feasibility study is also called as software requirement analysis. In this phase development team has to make communication with customers and make analysis of their requirement and analyze the system. By making analysis this way it would be possible to make a report of identified area of problem. By making a detailed analysis on this area a detailed document or report is prepared in this phase which has details like project plan or schedule of the project, the cost estimated for developing and executing the system, target dates for each phase of delivery of system developed and so on. This phase is the base of software development process since further steps taken in software development life cycle would be based on the analysis made on this phase and so careful analysis has to be made in this phase.
3. Systems Analysis and Design: This is an important phase in system development .Here analysis is made on the design of the system that is going to be developed. In other words database design, the design of the architecture chosen, functional specification design, low level design documents, high level design documents and so on takes place. Care must be taken to prepare these design documents because the next phases namely the development phase is based on these design documents. If a well structured and analyzed design document is prepared it would reduce the time taken in the coming steps namely development and testing phases of the software development life cycle.
4. Code Generation:
This is the phase where actual development of the system takes place. That is based on the design documents prepared in the earlier phase code is written in the programming technology chosen. After the code is developed generation of code also takes place in this phase. In other words the code is converted into executables in this phase after code generation.
5. Testing:
A software or system which is not tested would be of poor quality. This is because this is the phase where system developed would be tested and reports are prepared about bugs or errors in system. To do this testing phase there are different levels and methods of testing like unit testing, system test and so on. Based on the need the testing methods are chosen and reports are prepared about bugs. After this process the system again goes to development phase for correction of errors and again tested. This process continues until the system is found to be error free. To ease the testing process debuggers or testing tools are also available.
To develop reliable and good quality Program/Software we need to follow the following 5 steps :
1. Requirement Specification.
2. Analysis.
3. Design.
4. Implementation.
5. Verification and testing.
Internet Evolution
— The Internet is a network of networks
— Computer users on the Internet can contact one another anywhere in the world
— In Internet a huge resource of information is accessible to people across the world
— Information in every field starting from education, science, health, medicine, history, and geography to business, news, etc. can be retrieved through Internet
— You can also download programs and software packages from anywhere in the world
— In 1969 Department of Defense (DOD) of USA started a network called ARPANET (Advanced Research Projects Administration Network )
— Around 1970, NSFNET (National Science Foundation Network) was created. With the advancement of modern communication facilities,
— By 1990 many computers were looking up to NSFNET giving birth to Internet
— Internet is not a governmental organization.
— The ultimate authority of the Internet is the Internet Society.
— This is a voluntary membership organization whose purpose is to promote global information exchange.
— Internet has more than one million computers attached to it.
— Ten years of research brought Local Area Ethernet Networks (LANs) and workstations were developed to get connected to LAN.
— Computers connected to ARPANET used a standard or rule to communicate with each other with NCP (National Control Protocol).
— Protocol is a network term used to indicate the standard used by a network for communication.
— Rapid change in information technology suppressed NCP and brought TCP/IP (Transmission Control Protocol/Internet Protocol) in to the world of networking
— The Internet is a rare example of a large democracy with no state of head, no official censors, no bosses, no board of directors. Nobody controls the Internet and in principle, any computer can speak to any other computer, as long as it obeys the technical rules of the TCP/IP protocol.
— This freedom of Internet helped it to move out of its original base in military and research institutions, into elementary and high schools, colleges, public libraries, commercial sectors
Basic Internet Terminology
Blog - A blog is information that is instantly published to a Web site. Blog scripting allows someone to automatically post information to a Web site. The information first goes to a blogger Web site. Then the information is automatically inserted into a template tailored for your Web site.
Bookmark – a way of storing your favorite sites on the Internet. Browsers like Netscape or Internet Explorer let you to categorize your bookmarks into folders.
Browser – A software program that allows users to access the Internet. Examples:
Non-graphical a user interface for computers which allows you to read plain text, not pictures, sound, or video, on the Internet. It is strictly text based, non-Windows, and does not place high memory demands on your computer. An example is lynx .(http://lynx.browser.org/)
Graphical a user interface for computers which enables people to see color, graphics, and hear sound and see video, available on Internet sites. These features are usually designated by underlined text, a change of color, or other distinguishing feature; sometimes the link is not obvious, for example, a picture with no designated characteristic. Examples are Netscape and Internet Explorer.
CGI (Common Gateway Interface script) – a specificiation for transferring information between a Web server and a CGI program, designed to receive and and return data. The script can use a variety of languages such as C, Perl, Java, or Visual Basic. Many html pages that contain forms use a cgi program to process the data submitted by users/clients.
Chat – real-time, synchronous, text-based communication via computer.
Cookie – Information (in this case URLs, Web addresses) created by a Web server and stored on a user’s computer. This information lets Web sites the user visits to keep of a user’s browsing pattterns and preferences. People can set up their browsers to accept or not accept cookies.
Domain Name – A method of identifying computer addresses. Your e-mail address has a domain address. If you have an “edu” at the end of your e-mail address that means your account is affiliated with an educational institution. A “com” extension means you have a business account. A government account has a .gov suffix.
FTP – Using file transfer protocol software to receive from upload) or send to (download) files (text, pictures, spreadsheets, etc.) from one computer/server to another.
Home page - Generally the first page retrieved when accessing a Web site. Usually a “home” page acts as the starting point for a user to access information on the site. The “home” page usually has some type of table of contents for the rest of the site information or other materials. When creating Web pages, the “home” page has the filename “index.html,” which is the default name. The “index” page automatically opens up as the “home” page.
HTML – A type of text code in Hypertext Markup Language which, when embedded in a document, allows that document to be read and distributed across the Internet.
HTTP – The hypertext transfer protocol (http) that enables html documents to be read on the Internet.
Hypertext – text that is non-sequential, produced by writing in HTML (Hypertext Markup Language) language. This HTML coding allows the information (text, graphics, sound, video) to be accessed using HTTP (Hypertext Transfer Protocol).
Hyperlink – Text, images, graphics that, when clicked with a mouse (or activated by keystrokes) will connect the user to a new Web site. The link is usually obvious, such as underlined text or a “button” of some type, but not always.
Instant Messaging (IM) – a text-based computer conference over the Internet between two or more people who must be online at the same time. When you send an IM the receiver is instantly notified that she/he has a message.
IP Address – (Internet Protocol) The number or name of the computer from which you send and receive information on the Internet.
Modem – A device that connects your computer to the Internet, when you are not connected via a LAN (local area network, such as at work or on a campus.) Most people connect to a modem when using a home computer. The modem translates computer signals to analog signals which are sent via phone lines. The telephone “speaks” to the computer/server which provides your Internet access.
URL – A universal resource locator (a computer address) that identifies the location and type of resource on the Web. A URL generally starts with “http.”
Intranet: It is a relatively smaller private network that uses the Internet protocols and connectivity. It is an extension of the Internet and is privately used by organizations.
Web Server: A web server is a computer program that accepts HTTP requests from web clients and provides them with HTTP responses.
IP Address: It is a way of numerically identifying an entity on a computer network. The original addressing system known as IPv4, used 32 bit addresses. With the growth of the Internet, IPv6 came to be used wherein the addresses are composed of 128 bits. You might want to know how to find your IP address.
Internet Service Provider: A company, which provides users with an access to the Internet, is known as an Internet service provider or Internet access provider. ISP, as it is called, offers email accounts and other services like remote storage of files for its customers. Here is a word about choosing a cheap ISP.
Internet Address
— Every page on the Internet has a unique address.
— This address is used get the web page for user from Internet.
— The address on the Internet is known as URL (Uniform Resource Locator).
— A typical Internet address or URL would look like; http://www.mans.edu.eg/facscim/arabic/
— The URL contains the components that specify the protocol, server, and pathname of an item
URL parts
— The protocol is followed by a colon (http:),
— The server is preceded by two slashes (//www.mnmjec.edu.)
— Each segment of the pathname is preceded by a single slash /facscim/ /english/Tables/Default.htm).
— A protocol is set of rules that tells the computer know how to interpret the information at that address
— The first component, the protocol, defines the manner for interpreting computer information.
— Many Internet pages use HTTP (HyperText Transfer Protocol).
— Other common Internet protocols that one might come across are FTP (File Transfer Protocol),
— NEWS (Usenet news groups protocol), and
— GOPHER (an alternative transfer protocol). Gopher protocol is mostly out of date now.
— The second component, of the address is the server (www.mnmjec.edu), identifies the computer system that stores the information you seek and is always preceded by two slashes.
— A server is a computer that has information stored on it and sends it to the client, when a request is made.
— Each server on the Internet has a unique address name whose text refers to the organization maintaining the server.
— Most of the Web pages will have .htm or .html as their secondary or extension name.
Getting connected to Internet Applications
Types of Internet Connections
There are two main ways for users to connect to the Internet: through dial-up access or by using a LAN connection.
Dial-up Access Dial-up access allows access to the Internet over a standard telephone line by using a computer and a modem to dial into an ISP or VAN connection. Dial-up access is a feature typically included with the software provided by an ISP. Using a regular telephone line is usually the slowest telecommunications medium for setting up an individual Internet account through a dial-up ISP.
Local Area Network (LAN) Connection LAN connections provide faster and more direct Internet access by connecting users to an ISP on a direct wire, at speeds 30 or more times faster than can be achieved through a dial-up modem. Because they are more expensive than dial-up access, LAN connections are more commonly found in the workplace. Despite the increased cost there are approximately forty million LAN users in the United States using cable and DSL connections to connect from their homes.
Cable Modem Television cable companies provide a special modem and software for broadband (high-speed) Internet access. This service offers the advantage of simultaneous Web access and telephone calls, but is not available everywhere. In addition, the service slows down as more subscribers sign up in a neighborhood or location. The cost is about $50 monthly, plus a possible installation fee.
Digital Subscriber Line (DSL) DSL Internet service is as fast as cable modem and provides simultaneous Web access and telephone use, but the service is usually available only to users within three miles of the telephone carrier’s central switching office. The line is dedicated to one household, and is not shared with neighbors. DSL service costs around $50 monthly, plus an installation fee.
Wireless The fastest growing segment of Internet service involves wireless connections to the Internet. Thousands of Wireless “hot-spot” portals are springing up, allowing access in public places and even aboard airplanes.
— (i) Gateway Access
— Gateway Access is also known as Level-One connection.
— It is the access to the Internet from a network, which is not on the Internet.
— The gateway allows the two different types of networks to “talk” to each other. But the users of the Gateway Internet have limited access to the Internet.
— They might not be able to use all the tools available on Internet. The local Internet Service Provider (ISP) normally defines this limitation.
Dial-up Connection
— ‘Dial-up’ connection is also known as Level Two connection.
— This provides connection to Internet through a dial-up terminal connection.
— The computer, which provides Internet access is known as ‘Host’ and the computer that receives the access, is ‘Client’ or ‘Terminal’.
— The client computer uses modem to access a “host” and acts as if it is a terminal directly connected to that host.
— This type of connection is also known as ‘Remote Modem Access’ connection.
— And the host to which the client gets connected is actually connected to the Internet by a full time connection (See Leased Connection).
— In dial-up connection to Internet, Host carries all the command that are typed on a client machine and forward them to Internet.
— It also receives the data or information from the Internet on behalf of the ‘Client’ and passes it to them. The client computer acts as a ‘dumb’ terminal connected to remote host.
— This type of connection can further be divided into two categories.
Shell Connection
— In this type of Internet Connection, the user will get only textual matter of a Web Page.
— This connection does not support Graphics display. However the user will be able to surf the Internet, do FTP, receive mail.
— Shell Accounts were the only type of Internet access available for many years before the Internet entered in to the world of graphics and became more users friendly.
TCP/IP Connection
— Today’s graphical World Wide Web browsers provide easier access with multimedia sound and pictures.
— The major difference between Shell and TCP/IP account is that, Shell account can only display text and does not support graphics display, whereas TCP/IP can display both.
— Hence it is more popular Internet connection. Shell accounts are slowly phasing out from the Internet scenario
To access any of these dial-up accounts you need the followings;
$ computer, WebTV, personal digital assistant (PDA), or Web phone
$ dial-up modem, digital subscriber line (DSL) modem, or cable modem
$ telephone line or cable connection
$ telecommunications software
$ Web browser
$ an account with an Internet Service Provider (ISP)
Leased Connection
— Leased connection is also known as direct Internet access or Level Three connection. — It is the secure, dedicated and most expensive, level of Internet connection.
— With leased connection, your computer is dedicatedly and directly connected to the Internet using high-speed transmission lines.
— It is on-line twenty-four hours a day, seven days a week.
— Leased Internet connections are limited to large corporations and universities who could afford the cost.
Newer Internet Applications
Not only does the content of the Internet change daily, but they very way in which the Internet is used and understood as a communication medium is constantly evolving.
Peer-to-Peer File Sharing
Peer-to-Peer (P2P) file sharing allows people to download material directly from other users’ hard drives, rather than from files located on Web servers. Napster is famous for pioneering P2P file sharing.
Internet Telephony
Internet telephony is another increasingly popular way to use the Internet. By using this technology, also called Voice over IP (VoIP), two or more users with sufficiently good connections can use the Internet to make telephone calls around the world. Once their voices are digitized and broken down into packets, they can be transmitted anywhere, just like any other form of data. There are no long distance telephone charges, and users only pay their normal ISP connection fees.
Streaming Audio and Video
An alternative to downloading a piece of music or video is to access it using streaming techniques (also known as webcasting). Streaming sends a continuous stream of data to the receiving computer, where it is immediately displayed. Old data is erased as new data arrives.
Webcams
Tiny video cameras called webcams allow conversations over the Web through live video transmission. Often mounted on top of a computer monitor, the cameras automatically create and transmit video to the PC. Despite the fact that the images are a bit grainy and jerky, millions are in use. As the technology improves, their popularity is sure to increase even further.
Audio Mail
Audio mail is a fledgling type of electronic mail that allows people to transmit messages by voice. As with e-mail, attachments can be included. The technology can be compared to voice mail, without telephone charges.
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