A microprocessor is an electronic device capable of manipulating data to produce desired results. The functions of a digital computer are performed using the microprocessor’s arithmetic, logic and control circuitry. It essentially consists of several hundred thousands, or perhaps even billions of tiny transistors on a single integrated circuit.
Every microprocessor depends on an ‘instruction set’, which is designed to program it to perform specialized functions.

Main parts of microprocessors

Microprocessors consist of several different parts:

1. The arithmetic and logic unit (ALU), which performs calculations and logical outputs.
2. Registers, in which temporary data is stored.
3. The control unit which decodes the programs fed into the processor.
4. The address, data and control buses, which exchange information to and from the various parts of the microprocessor system.

More advanced microprocessors series consist of an additional component called the cache memory that speeds up memory access and processing.
A crystal oscillator in a computer system provides a clock signal to govern the functioning of the microprocessor, helping it carry out billions of instructions per second.

Types and uses
Microprocessors are popularly classed according to the number of bits that they can manipulate. For instance, a microprocessor with an arithmetic and logic unit which can manipulate data 4-bits wide is referred to as a 4-bit microprocessor. This form of classification does not take into account the number of address bus lines (the channel which sends out addresses of memory locations or ports) or data bus lines (the channel which sends data to/from memory or ports).
Another way of classing microprocessors is as embedded controllers, also referred to as dedicated controllers or microcontrollers. These pre-programmed devices consist of not just a basic microprocessor, but also random-access memory (RAM), read-only memory (ROM) and input/output capabilities all integrated onto one and the same chip. These are used to control ‘smart machines’ such as programmable washing machines and microwave ovens.
One or more microprocessors typically make up a central processing unit (CPU) in a particular application using a computer system. In this way, scientific and business tasks can be effectively handled. Microprocessors are needed for a wide variety of applications from simple calculators to the largest mainframe computers and hand-helds.

History and development
The earliest microprocessors appeared in the 1970s with the development of Large Scale Integration (LSI) in integrated circuit technology, which made it possible to accommodate several thousand transistors, resistors and diodes onto a single silicon chip. With the advent of Very Large Scale Integration (VLSI) in the 1980s it became possible to fit several hundred thousand components onto chips not larger than 5mm square in size.
Some of the earliest microprocessors were Intel’s 4004 and Texas Instruments’ TMS 1000, both 4-bit microprocessors. Later, the 8-bit Intel 8008 was made in 1972. The more advanced 8080 had a larger instruction set than its predecessors. It used NMOS transistors, and was referred to as a second generation microprocessor. Around the same time, Motorola came up with its MC6800, also an 8-bit microprocessor.

Embedded controllers
An evolution in three different directions has been seen as far as microprocessors are concerned. The first direction is that of the embedded controllers. Examples are the 8051 series of Intel and Atmel’s 89C51/2.

Bit-slice processors
A second direction has been that of the bit-slice processors. Bit-slice processors have components that can work in parallel to manipulate 8-bit, 16-bit or 32-bit words. AMD’s 2900 family of processors is an example of this category.

The Internet - How it began.....

The Internet was the result of some visionary thinking by people in the early 1960s who saw great potential value in allowing computers to share information on research and development in scientific and military fields. J.C.R. Licklider of MIT, first proposed a global network of computers in 1962, and moved over to the Defense Advanced Research Projects Agency (DARPA) in late 1962 to head the work to develop it. Leonard Kleinrock of MIT and later UCLA developed the theory of packet switching, which was to form the basis of Internet connections. Lawrence Roberts of MIT connected a Massachusetts computer with a California computer in 1965 over dial-up telephone lines. It showed the feasibility of wide area networking, but also showed that the telephone line's circuit switching was inadequate. Kleinrock's packet switching theory was confirmed. Roberts moved over to DARPA in 1966 and developed his plan for ARPANET. These visionaries and many more left unnamed here are the real founders of the Internet.
The Internet, then known as ARPANET, was brought online in 1969 under a contract let by the renamed Advanced Research Projects Agency (ARPA) which initially connected four major computers at universities in the southwestern US (UCLA, Stanford Research Institute, UCSB, and the University of Utah). The contract was carried out by BBN of Cambridge, MA under Bob Kahn and went online in December 1969. By June 1970, MIT, Harvard, BBN, and Systems Development Corp (SDC) in Santa Monica, Cal. were added. By January 1971, Stanford, MIT's Lincoln Labs, Carnegie-Mellon, and Case-Western Reserve U were added. In months to come, NASA/Ames, Mitre, Burroughs, RAND, and the U of Illinois plugged in. After that, there were far too many to keep listing here.
The Internet was designed in part to provide a communications network that would work even if some of the sites were destroyed by nuclear attack. If the most direct route was not available, routers would direct traffic around the network via alternate routes.
The early Internet was used by computer experts, engineers, scientists, and librarians. There was nothing friendly about it. There were no home or office personal computers in those days, and anyone who used it, whether a computer professional or an engineer or scientist or librarian, had to learn to use a very complex system.
E-mail was adapted for ARPANET by Ray Tomlinson of BBN in 1972. He picked the @ symbol from the available symbols on his teletype to link the username and address. The telnet protocol, enabling logging on to a remote computer, was published as a Request for Comments (RFC) in 1972. RFC's are a means of sharing developmental work throughout community. The ftp protocol, enabling file transfers between Internet sites, was published as an RFC in 1973, and from then on RFC's were available electronically to anyone who had use of the ftp protocol.
The Internet matured in the 70's as a result of the TCP/IP architecture first proposed by Bob Kahn at BBN and further developed by Kahn and Vint Cerf at Stanford and others throughout the 70's. It was adopted by the Defense Department in 1980 replacing the earlier Network Control Protocol (NCP) and universally adopted by 1983.
The Unix to Unix Copy Protocol (UUCP) was invented in 1978 at Bell Labs. Usenet was started in 1979 based on UUCP. Newsgroups, which are discussion groups focusing on a topic, followed, providing a means of exchanging information throughout the world . While Usenet is not considered as part of the Internet, since it does not share the use of TCP/IP, it linked unix systems around the world, and many Internet sites took advantage of the availability of newsgroups. It was a significant part of the community building that took place on the networks.
Similarly, BITNET (Because It's Time Network) connected IBM mainframes around the educational community and the world to provide mail services beginning in 1981. Gateways were developed to connect BITNET with the Internet and allowed exchange of e-mail, particularly for e-mail discussion lists. 
In 1986, the National Science Foundation funded NSFNet as a cross country 56 Kbps backbone for the Internet. They maintained their sponsorship for nearly a decade, setting rules for its non-commercial government and research uses.
As the commands for e-mail, FTP, and telnet were standardized, it became a lot easier for non-technical people to learn to use the nets. It was not easy by today's standards by any means, but it did open up use of the Internet to many more people in universities in particular. Other departments besides the libraries, computer, physics, and engineering departments found ways to make good use of the nets--to communicate with colleagues around the world and to share files and resources.
In 1991, the first really friendly interface to the Internet was developed at the University of Minnesota. The University wanted to develop a simple menu system to access files and information on campus through their local network. A debate followed between mainframe adherents and those who believed in smaller systems with client-server architecture. The mainframe adherents "won" the debate initially, but since the client-server advocates said they could put up a prototype very quickly, they were given the go-ahead to do a demonstration system. The demonstration system was called a gopher after the U of Minnesota mascot--the golden gopher. The gopher proved to be very prolific, and within a few years there were over 10,000 gophers around the world. It takes no knowledge of unix or computer architecture to use. In a gopher system, you type or click on a number to select the menu selection you want.
In 1989 another significant event took place in making the nets easier to use. Tim Berners-Lee and others at the European Laboratory for Particle Physics, more popularly known as CERN, proposed a new protocol for information distribution. This protocol, which became the World Wide Web in 1991, was based on hypertext--a system of embedding links in text to link to other text, which you have been using every time you selected a text link while reading these pages. Although started before gopher, it was slower to develop.

The development in 1993 of the graphical browser Mosaic by Marc Andreessen and his team at the National Center For Supercomputing Applications (NCSA) gave the protocol its big boost. Later, Andreessen moved to become the brains behind Netscape Corp., which produced the most successful graphical type of browser and server until Microsoft declared war and developed its Microsoft Internet Explorer.

Since the Internet was initially funded by the government, it was originally limited to research, education, and government uses. Commercial uses were prohibited unless they directly served the goals of research and education. This policy continued until the early 90's, when independent commercial networks began to grow. It then became possible to route traffic across the country from one commercial site to another without passing through the government funded NSFNet Internet backbone.
Delphi was the first national commercial online service to offer Internet access to its subscribers. It opened up an email connection in July 1992 and full Internet service in November 1992. All pretenses of limitations on commercial use disappeared in May 1995 when the National Science Foundation ended its sponsorship of the Internet backbone, and all traffic relied on commercial networks. AOL, Prodigy, and CompuServe came online. Since commercial usage was so widespread by this time and educational institutions had been paying their own way for some time, the loss of NSF funding had no appreciable effect on costs.
Today, NSF funding has moved beyond supporting the backbone and higher educational institutions to building the K-12 and local public library accesses on the one hand, and the research on the massive high volume connections on the other.
Microsoft's full scale entry into the browser, server, and Internet Service Provider market completed the major shift over to a commercially based Internet. The release of Windows 98 in June 1998 with the Microsoft browser well integrated into the desktop shows Bill Gates' determination to capitalize on the enormous growth of the Internet. Microsoft's success over the past few years has brought court challenges to their dominance. We'll leave it up to you whether you think these battles should be played out in the courts or the marketplace.

A current trend with major implications for the future is the growth of high speed connections. 56K modems and the providers who support them are spreading widely, but this is just a small step compared to what will follow. 56K is not fast enough to carry multimedia, such as sound and video except in low quality. But new technologies many times faster, such as cablemodems, digital subscriber lines (DSL), and satellite broadcast are available in limited locations now, and will become widely available in the next few years. These technologies present problems, not just in the user's connection, but in maintaining high speed data flow reliably from source to the user. Those problems are being worked on, too.
During this period of enormous growth, businesses entering the Internet arena scrambled to find economic models that work. Free services supported by advertising shifted some of the direct costs away from the consumer--temporarily. Services such as Delphi offered free web pages, chat rooms, and message boards for community building. Online sales have grown rapidly for such products as books and music CDs and computers, but the profit margins are slim when price comparisons are so easy, and public trust in online security is still shaky. Business models that have worked well are portal sites, that try to provide everything for everybody, and live auctions. AOL's acquisition of Time-Warner was the largest merger in history when it took place and shows the enormous growth of Internet business! The stock market has had a rocky ride, swooping up and down as the new technology companies, the dot.com's encountered good news and bad. The decline in advertising income spelled doom for many dot.coms, and a major shakeout and search for better business models is underway by the survivors.
It is becoming more and more clear that many free services will not survive. While many users still expect a free ride, there are fewer and fewer providers who can find a way to provide it. The value of the Internet and the Web is undeniable, but there is a lot of shaking out to do and management of costs and expectations before it can regain its rapid growth.