History of Computers : Part-3

1) History Of Computers : Part-1

2) History Of Computers-part-2

John Von Neumann, originator of the stored program concept, developed the IAS (Institute for Advanced Study) computer at Princeton University. This machine was the realization of John Von Neumann ideas on computer design. Most computers built after the IAS computer have "Von Neumann ideas on computer design. Most computers built after the IAS computer have "Von Neumann " characteristics.

A group of scientists at MIT in USA headed by Ken Olsen developed the Whirlwind computer, which was more than twenty times faster than the ENIAC. Both the IAS and Whirlwind computers introduced computational innovations of astronomical proportions. Computers were not available commercially until early 1951. In 1951, the Sperry Rand Corporation of USA built the UNIVAC. The UNIVAC I built for the Bureau of Census of the United States was the first commercially available computer. The first computer installation to handle business applications was set up in 1954 at Louisville, Kentucky, USA. The UNIVAC I is now on display in the Smithsonian Institution in Washington D.C in USA.

Day by day computers were becoming smaller, faster, and more powerful. In 1956, MIT in the USA introduced its compact TX-0 transistorized computer system. A few years later, in 1960, the first integrated circuit was produced by Jack Kilby of Texas Instruments in USA and the DEC PDP-1 minicomputer was developed. In the Mid 1960s, minicomputer began appearing as a forerunner of mainframes and supercomputers. The intention of microprocessor in 1971 began a new ara and microcomputers based on microprocessors began to appear from the Mid-1970s. Microcomputers provide the driving force of the present information age.


History of Computers : Part-2

 1) History Of Computers Part-1

1) History Of Computer Part-3

Insignificant progress took place over the next decades. In the United States the 1890 census was approaching, and there was on way that it could be completed by 1900, as required by the constitution. Herman Hollerith, an employee of the Census Office Washington, started to develop an automated device to complete this task in ten years. The result was Holleriths tabulator. A manual card puncher, a card reader, and an electromechanical card sorter were the main components of this machine.

With this tabulator, Hollerith was able to complete the census calculations in only two years. Holleriths success paved the way for further research and development. Analog computers, a new class of computing devices, emerged. These devices used electrical voltages to represent physical quantities. They functioned by establishing an analogy between a physical quantity and a voltage level. They were very east but not sufficiently accurate.

The first electronic computers, the ABC (Atanasoff Berry Computer) and the ENIAC (Electronic Numerical Integrator And Calculator) were built in USA in the early 1940s. The ABC, built by Atanasoff and Berry, was the first electronic computer using vacuum tubes. The ENIAC, built by Eskert and Mauchly, was an special purpose computer. In first general purpose electroic computer operating under the control of a stored program, was completed. A stored program is a set of instructions stored in memory that guides the computer, step by step, through a process.


History of Computers : Part -1

Different devices and tools have been used in calculation and processing of data. An ancient calculating device is the abacus, a mechanical calculating device first used around 2500 BC to add and subtract. Scientists and mathematicians later sought other means for calculations. John Nepier, a Scottish mathematician, developed a series of rods made of comes that could be arranged to generate the products of selected numbers. If used these rods to produce the first table of logarithms. In 1865 French mathematician Blase Pascal improved on this concept and produced a mechanical calculator called Pascaline was capable of performing all the four arithmetic operations and producing mathematical tables quickly and accurately were not successful until 1820. Thomas De Colmar of France produced the arithmometer, the first four-function practical mechanical calculator in 1920.

A young English mathematician named Charles Babbage of Cambridge University contributed substantially towards the development of computers. Babbage gave much thought to the design of a device to produce mathematical and navigational tables and came upon a principle that used the "differences" between previous values in a table to produce new values. Babbage was able to construct a working model to illustrate the principle of the difference engine. Babbage thought of a steam-driven version of the difference engine. Babbage thought of a steam-driven version of the difference engine capable of calculating and printing results at a rate of two twenty-digit numbers per minute.

Babbage built part of the difference engine but abandoned it in favor of a more powerful and versatile machine, the analytical engine. The analytical engine was designed to use punched cards to provide a constan flow of information through the machines elaborate series of columns, gears, wheels, and levers. The analytical engine included all the functional units of a modern computer ; input of data, arithmetic unit for computation, memory for data and instructions, and display for output. This was an ambitious project during a time when electronics, transistors, and chips did not exist. The engine was a puzzle to all but a few mathematicians. This machine, however, was never built. Nearly a century later a new generation of scientists and engineers equipped with new developments brought Babbages vision back into focus.


Goal-line technolog by 2014 worldcup in Braazil

FIFA President Sepp Blatter said he would welcome the use of technology to the goal line in the 2014 World Cup in Brazil, if a suitable system can be found.

Ten systems are not met FIFA requirements for the exam in the last month, but the standard soccer body today agreed to extend for another year of study.
"Goal-line technology allows referee," Blatter said after the meeting of the International Football Association Board.
Blatter has compared high-tech to help referee: missing a goal for England have reversed, though the ball clearly crossed the finish line in the first round against Germany Cup World 2010. He called for "fundamental errors ... and huge."

Were the goal, tied the game 2-2, but Germany won 4-1.
In an attempt to eliminate such errors in the tournament in 2014, said the International Football Association Board held further testing in games held at FIFA headquarters in Zurich conducted.

The decision on the goal-line technology is planned for March 2012.  Blatter hopes Technology more tests to be held under the terms of the game, a measurement system on controversial goals in a second rule with the highest accuracy.

"We will continue with technical experience and bring this matter to the meeting of the IFAB in London next year, and then the final decision is made," said Blatter. "If it works, certainly, the board said yes to the technology. And if the board says yes, then no problem, then there should be no problem in 2014.
"I have my natural optimism and back limits are a little bit, because the evidence that we are not yet conclusive.
The English Football Association, which was one of the eight votes IFAB not happy that the test took only.
"It's not perfect, because I wanted the principle already adopted the goal-line technology," said Alex Horne, the general secretary of the FA. "Considering where we were last year, when thrown, that was my worst fear, that it happens again.

"My favorite position was to accept the principle and expect to be detected by the technology. We are now in a position where you see the technology in different environments and then we will decide, in March next year want. It the next meeting of the year will be very important. "
The IFAB has approved the use of two additional assistant referees "at the Euro 2012 in Poland and Ukraine, after successful tests on the basis of five officials of UEFA, Michel Platini, president of the League of the System Europe.

The system of five officers could also be used in the World Cup, Blatter said.
"It is with great optimism that we have additional referees in 2014," said Blatter.
In a decision that he does not like some football teams will play in the cold, the players move IFAB not use the neck warmer. The ban is effective immediately.

"It was not even a discussion because it is part of the uniform and can be dangerous," said Blatter.
The Board also decided that the experience in South America for the referee to use a spray to approve the disappearance or free-standing walls mark.
In a further change in July, officials said stop playing when a lost object, like an extra ball or an animal appears in the field. In 2009, Daren doubled scored for Sunderland against Liverpool, when the ball deflected by a beach ball.

The IFAB is an organization of 125 years, representatives from England, Northern Ireland, Scotland and Wales, and FIFA, the countries and 204 soccer referees, coaches and players all over the world.
Each member has one vote UK, FIFA has four, and a proposed new rule requires six votes to pass.


Organization of a Microcomputer : Packaging Style

Microcomputer system units have evolved to a number of packaging styles, primarily to support different levels of expansion capability and ergonomic needs of the user.

For desktop designs the packaging changed very little over the years. Developers have maintained the basic design and simply dress up the systems with unique front designs and custom colours and logos. The basic layout and partitioning of function usually remains intact. Other mechanical packages have evolved to meet specific needs not addressed by the basic desktop design. The tower package added significant needs not capacity. This includes space for additional disk drives and hard drives and in some designs, additional bus expansion slots. Tower designs often had larger power supplies and additional cooling fans to support these expansion features.

There are a number of packages supporting portable microcomputers. These range from the large, barely transportable systems to the very small palmtop devices. The basic concept of a portable system is to integrate all the functions into a single device. Some compromises have to be made to achieve the size and weight desired. Displays are usually smaller flat panel devices, expansion slots are limited, and keyboard size and layout are reduced. In the smallest designs, floppy and hard disk drivers are replaced with other more compact memory technologies.

Notebooks are partitioned into two basic categories, notebooks and sub notebooks. The primary difference is the presence or absence of a floppy disk drive and the smaller screen in the sub-notebooks, sub-notebooks seem to be losing some of their popularity as notebooks become lighter, approaching the weight of a sub-notebook. Also contributing to their decline is the difficulty of typing on small keyboards and smaller screen sizes.


Organization of a Microcomputer : Hardware Organization Part-6

I gonna to write now Organization of a Microcomputer : Hardware Organization Part -6 and last part. So dont wait see this last part of Microcomputer Hardware Organization.

CD-ROM Drives :
A CD-ROM drive is capable of storing over 600MB of data on a single 5-inch disk. CD-ROMs are suitable for distribution of large software packages and can contain all types of multimedia data. The CD-ROM technology is low cost and easy to produce. In future it will be possible to save data or programs on a CD-ROM in real-time, similar to a floppy disk. CD-ROM drives can be installed in the same size drive bays as a 5.25-inch floppy disk drive. The CD-ROM drive interfaces to the microcomputer through one of several port adapters. Often, a SCSI adapter comes with the CD-ROM drives are now capable of being attached to the IDE adapter port. The IDE port adapter standard has recently been extended to support additional IDE posts with CD-ROM attachment capability.

Microcomputer System Unit :
Most of the intelligence and functioning of a PC system resides in the system unit. All external input/output devices are attached to the system unit and upgrade and expansion features are installed in the system unit. The system unit is the heart of the microcomputer figure 4.3 is a they of the inside of a desktop microcomputer system unit. The drive bays accept hard disk drives, floppy disk drives and CD-ROM drive of various physical sizes. The motherboard is installed on the case of the system unit. The processor, cache memory, system DRAM , core logic chip set, integrated adapters and ports, BIOS ROM, and expansion slots are mounted on the motherboard. What is actually in a microcomputer depends on the PCs packaging style and its bus architecture.


Organization of a Microcomputer : Hardware Organization Part-5

1) Organization of a Microcomputer Part-4

This is Organization of a Microcomputer : Microcomputer Organization Part-5.

Floppy Disk Drives :
All Microcomputer with the exception of some notebooks and palmtop devices, support one floppy disk drive. The floppy disk is a data distribution medium because it is removable after it is read or written. Data and programs can be moved from system to system by storing them on floppy disks. Also, software is sold or distributed on floppy disks. Early floppy disks were 5.25 inches in diameter and used to store from 160KB to 1.2MB of data. A smaller 3.5 inch disk introduced later stores up to 2.88MB of data. Most PCs equipped with 3.5 inch floppy disk dives. Most PCs come with floppy disk drive adapters that support a minimum of two drives.

Hard Disk Drives :
The hard disk drive is used for high-speed access and storage of programs and data. It is a nonvolatile rotating medium similar to the floppy disk. However, it is not flexible, hence the name hard disk. It is capable of storing much more data at significantly higher speeds than the floppy disk drives. Todays typical hard drives stores from 8GB to more than 40GB of data with access times below 10 milliseconds. Hard drives come in several package sizes with disk media or platter sizes from 8 inches to under 1.8 images in diameter. Most Microcomputer hard drives are 3.5 images in diameter, enabling them to fit in the same drive bays as 3.5 inch floppy disk drives. Hard drives attach to a Microcomputer through and Intelligent Drive Electronics or Small Computer Systems Interface adapter port.
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Organizaton of Microcomputer : Hardware Organization Part-4

This is part 4 of a Organization of a Microcomputer : Hardware Organization.

Other Ports and Adapters :
Most Microcomputers today come with two serial communication (COM) posts and a game port. Often one of the serial communications posts is used to attach the mouse. These serial ports support data rates up to 115 kb/second using an asynchrononts start/stop serial protocol. This protocol spandp the serial data that are transmitted to the interfaces. The electrical interface is called an RS-233-C standard interface. The two COM posts are accesssale at the rear of the system unit as either 9-pin or 25-pin D connectors. The COM ports are typically created using a UART ( Universal Asyn Chronous Receives Transmitter ) chip attached to the processors bus. Sometimes the chip is integrated on the system units main boards, but most often it is installed on an adapter board in one of the bus expansion slots. Often it is combined with other adapters on a single board called a multi-I/O adapter board. A game port connector is often on the same multi-I/O adapter board.

Power Supply :
The PC power supply converts the standard wall outlet 220 volt AC to DC voltages to run the electronics and peripheral devices in the microcomputer. This power supply unit also supplies AC voltage to the system display monitor through an mouldu on the power supply. The power supply converts the AC voltage to four DC voltages : +5 volts, +12 volts, -5 volts, -12 volts. Today most desktop units come desktop units come with power supplies rated at between 150 and 220 watts. Tower designs are typically saved at 200 to 400 watts. If a large number of hard driver and adapter boards are to be installed in a tower watts. If a large number of hardc drivers and adapter boards are to be installed in a tower system a minimum of 272 watts should be sufficient.

Cooling :
In most desktop and mini-tower systems cooling is provide by the power supply fans. This fan is used to cool both the power supply and the system unit. In larger tower systems, separate cooling fans may be necessary. One fan cools the power supply and the second fan cools the motherboard and the adapter boards. With the newer high performance CPUs often a fan is attached to the CPU.


Organization of a Microcomputer : Hardware Organizatio Part -3

I gonna to now, Organization of a Microcomputer : Hardware Organization Part-3. To day i write two common things of computer Keyboard and Mouse.

Printer :

A Printer is attached to the system unit through a parallel port, also called the printer port. In a paralle port, data transferred 8 bits at a time in parallel, as compared to the keyboard port where data are transferred in a serial mode, one bit at a time. Tin printer or parallel port is sometimes referred to as bentsnogar printer port. Early printers manufactured by a company called bentsnogar defined a parallel port interface for their printers and this interface was selected by IBM on the original PC.

Most microcomputer come with parallel or printer port as standard, sometimes the parallel port adapter is integrated on the systems units motherboard and sometimes it is on an adapter board installed in one of the expansion bus slots. To save expansion slots, the printer port function may be included on a multi-I/O port adapter board supporting several commonly used ports and adapters.

Three basic types of printers are popular for microcomputers. They are wire matrix impact printers, laser printers, and ink jet printers.

Mouse :

The Mouse is now the preferred input device for navigation through an application. The mouse is attached to the system unit in different ways. On most microcomputers, the mouse is attached using one of the two asynchronous communications ports, or COM ports. The Mouse detects motion on a surface and sends tracking information to mouse port.

Okay bye now, next part will coming soon.


Organization of a Microcomputer : Hardware Organization Part-2

Hello, I gonna to know to day Organization of a Microcomputer : Hardware Organization Part-2.

Display :

The main output device for a microcomputer is the display device. In most microcomputers the display device is a Cathode Ray Tube ( CRT)G In Notebooks, it is often a flat panel device known as Liquid Crystal Display (LCD). The term monitor is used to describe the CRT display. This display monitor is very similar to a TV, but is designed to be viewed at much higher rates, typically more than 72 frames per second. The TV Displays images at only 30 frames per second.

The PC systems today use 14-,15-, and 17-inch displays. Larger displays are available but are very costly. High resolution and high refresh rates are needed to display computer generated text and images that do not flicker when viewed at close range. At present PC displays are able to display images with pixel resolutions in the 1024*768 range. This means 768 horizontal lines where each line contains 1024 picture elements or pixels. A pixel is the smallest picture element that can be created and displayed by the display monitor.

The monitor is attached to the computer through a short cable attached to the system units display adapter port. The display adapter attaches to the system bus. The display adapter is either integrated on the motherboard with the processor or installed as a separate adapter board so one slots of the expansion of the motherboard.

Keyboard :

Keyboard are sold with adapter plugs that can connect the keyboard to the keyboard port. An 8-bit microprocessor inside the keyboard is programmed to continuously scan the keyboard and report key presses and releases to the keyboard adapter. A keyboard adapter actually contains another 8-bit microprocessor that communicates with the keyboradr microprocessor and send the keystroke to the main processor through the system bus.


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