3rd PROJECT-5 Generations of Computers

5 Generations of Computers

First Generation (1940-1956) Vacuum Tubes

The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.

First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.

The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

                              

Second Generation (1956-1963) Transistors

Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.

Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.

The first computers of this generation were developed for the atomic energy industry.

                                                                                             

Third Generation (1964-1971) Integrated Circuits

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

                                                                                                      

Fourth Generation (1971-Present) Microprocessors

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.

In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.

As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.

                                                                                                             

Fifth Generation (Present and Beyond) Artificial Intelligence

Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

                                     

            

                                 

2nd PROJECT - ICT AND MULTIMEDIA FUNDAMENTALS II

INTERNET

The Internet is a global network connecting millions of computers. More than 100 countries are linked into exchanges of data, news and opinions. According to Internet World Stats, as of December 31, 2011 there was an estimated 2,267,233,742 Internet users worldwide. This represents 32.7% of the world's population.

Unlike online services, which are centrally controlled, the Internet is decentralized by design. Each Internet computer, called a host, is independent. Its operators can choose which Internet services to use and which local services to make available to the global Internet community. Remarkably, this anarchy by design works exceedingly well. There are a variety of ways to access the Internet. Most online services offer access to some Internet services. It is also possible to gain access through a commercial Internet Service Provider (ISP).

WORLD WIBE WEB

A system of Internet servers that support specially formatted documents. The documents are formatted in a markup language called HTML (HyperText Markup Language) that supports links to other documents, as well asgraphics, audio, and video files. This means you can jump from one document to another simply by clicking on hot spots. Not all Internet servers are part of the World Wide Web.

There are several applications called Web browsers that make it easy toaccess the World Wide Web; Two of the most popular being Firefox andMicrosoft's Internet Explorer.

INTERNET SERVICES

• ELECTRONIC MAIL

Short for electronic mail, the transmission of messages over communications networks. The messages can be notes entered from the keyboard or electronic files stored on disk. Most mainframes, minicomputers, and computer networks have an e-mail system. Some electronic-mail systems are confined to a single computer system or network, but others have gateways to other computer systems, enabling users to send electronic mail anywhere in the world. Companies that are fully computerized make extensive use of e-mail because it is fast, flexible, and reliable.

Most e-mail systems include a rudimentary text editor for composing messages, but many allow you to edit your messages using any editor you want. You then send the message to the recipient by specifying the recipient's address. You can also send the same message to several users at once. This is called broadcasting.

Sent messages are stored in electronic mailboxes until the recipient fetches them. To see if you have any mail, you may have to check your electronic mailbox periodically, although many systems alert you when mail is received. After reading your mail, you can store it in a text file, forward it to other users, or delete it. Copies of memos can be printed out on a printer if you want a paper copy.

All online services and Internet Service Providers (ISPs) offer e-mail, and most also support gateways so that you can exchange mail with users of other systems. Usually, it takes only a few seconds or minutes for mail to arrive at its destination. This is a particularly effective way to communicate with a group because you can broadcast a message or document to everyone in the group at once.

Although different e-mail systems use different formats, there are some emerging standards that are making it possible for users on all systems to exchange messages. In the PC world, an important e-mail standard is MAPI. The CCITT standards organization has developed the X.400 standard, which attempts to provide a universal way of addressing messages. To date, though, the de facto addressing standard is the one used by theInternetsystem because almost all e-mail systems have an Internet gateway.


                                                     

• VIDEO CONFERENCING 

Conducting a conference between two or more participants at different sites by using computer networks to transmit audio and video data. For example, a point-to-point (two-person) video conferencing system works much like a video telephone. Each participant has a video camera, microphone, and speakers mounted on his or her computer. As the two participants speak to one another, their voices are carried over the network and delivered to the other's speakers, and whatever images appear in front of the video camera appear in a window on the other participant's monitor.

 Multipoint video conferencing allows three or more participants to sit in a virtual conference room and communicate             as if they were sitting right next to each other. Until the mid 90 s, the hardware costs made video conferencing    prohibitively expensive for most organizations, but that situation is changing rapidly. Many analysts believe that video conferencing will be one of the fastest-growing segments of the computer industry in the latter half of the decade.

• SOCIAL MEDIA NETWORK

Social media refers to the means of interactions among people in which they create, share, and exchange information and ideas in virtual communities and networks. Examples :

Facebook

Facebook is an online social networking service, whose name stems from the colloquial name for the book given to students at the start of the academic year by some university administrations in the United States to help students get to know each other. 

  


 Twitter

Twitter is an online social networking service and micro blogging service that enables its users to send and read text-based messages of up to 140 characters, known as "tweets".

                                            

     

  KEEK      

 Keek is a free online social networking service that allows its users to upload video status updates, which are called "keeks". Users can post keeks to the keek website using a webcam or via the Keek mobile apps for iPhone, Android, BlackBerry or Windows Phone.

  

                               

Youtube

YouTube is a video-sharing website, created by three former PayPal employees in February 2005 and owned by Google since late 2006, on which users can upload, view and share videos.

                                 

• BLOG

A blog is a type of website that is usually arranged in chronological order from the most recent ‘post’ (or entry) at the top of the main page to the older entries towards the bottom.

Blogs are usually (but not always) written by one person and are updated pretty regularly. Blogs are often (but not always) written on a particular topic – there are blogs on virtually any topic you can think of. From photography, to spirituality, to recipes, to personal diaries to hobbies – blogging has as many applications and varieties as you can imagine. Whole blog communities have sprung up around some of these topics putting people into contact with each other in relationships where they can learn, share ideas, make friends with and even do business with people with similar interests from around the world.

                                            

• INTERNET RELAY CHAT

Internet Relay Chat or IRC has become very popular as more people get connected to the Internet because it enables people connected anywhere on the Internet to join in live discussions. Unlike older chat systems, IRC is not limited to just two participants.

To join an IRC discussion, you need an IRC client and Internet access. The IRC client is a program that runs on your computer and sends and receives messages to and from an IRC server. The IRC server, in turn, is responsible for making sure that all messages are broadcast to everyone participating in a discussion. There can be many discussions going on at once; each one is assigned a unique channel.

                               

• ONLINE SHOPPING

Online shopping or online retailing is a form of electronic commerce which allows consumers to directly buy goods or services from a seller over the Internet using a web browser. Alternative names are: e-web-store, e-shop, e-store, Internet shop, web-shop, web-store, online store, and virtual store.

   

• SEARCH ENGINE

Search engines are programs that search documents for specified keyword sand returns a list of the documents where the keywords were found. A search engine is really a general class of programs, however, the term is often used to specifically describe systems like Google, Bing and Yahoo! Search that enable users to search for documents on the World Wide Web.

            

                             

• NEWSGROUP

A newsgroup is an Internet-based discussion about a particular topic. These topics range from sports, cars, investing, teen problems, and some stuff you probably don't want to know about. Users post messages to a news server which then sends them to a bunch of other participating servers. Then other users can access the newsgroup and read the postings. The groups can be either "moderated," where a person or group decides which postings will become part of the discussion, or "unmoderated," where everything posted is included in the discussion.

                                             

• MAILING LIST

A mailing list is a list of people who subscribe to a periodic mailing distribution on a particular topic. On the Internet, mailing lists include each person's e-mail address rather than a postal address. Mailing lists have become a popular way for Internet users to keep up with topics they're interested in. Many software producers and other vendors are now using them as a way to keep in touch with customers.

                                             

         REFERENCES

• whatis.techtarget.com
• www.webopedia.com
• en.wikipedia.org 
• www.harley.com

                                                                     

1st PROJECT - ICT AND MULTIMEDIA FUNDAMENTALS

1.Type of transmission media

The means through which data is transformed from one place to another is called transmission or communication media. There are two categories of transmission media used in computer communications.

• BOUNDED/GUIDED MEDIA
• UNBOUNDED/UNGUIDED MEDIA

BOUNDED/GUIDED MEDIA

Bounded media are the physical links through which signals are confined to narrow path. These are also called guide media. Bounded media are made up o a external conductor (Usually Copper) bounded by jacket material. Bounded media are great for LABS because they offer high speed, good security and low cast. However, some time they cannot be used due distance communication. Three common types of bounded media are used of the data transmission. These are

• Coaxial Cable
• Twisted Pairs Cable
• Fiber Optics Cable

Coaxial Cable

Coaxial cable is very common & widely used commutation media. For example TV wire is usually coaxial.

Coaxial cable gets its name because it contains two conductors that are parallel to each other. The center conductor in the cable is usually copper. The copper can be either a solid wire or stranded martial.

Outside this central Conductor is a non-conductive material. It is usually white, plastic material used to separate the inner Conductor form the outer Conductor. The other Conductor is a fine mesh made from Copper. It is used to help shield the cable form EMI.

Outside the copper mesh is the final protective cover. (as shown in Fig)

The actual data travels through the center conductor in the cable. EMI interference is caught by outer copper mesh. There are different types of coaxial cable vary by gauge & impedance.

Gauge is the measure of the cable thickness. It is measured by the Radio grade measurement, or RG number. The high the RG number, the thinner the central conductor core, the lower the number the thicker the core.

CHARACTERISTICS OF COAXIAL CABLE

·         Low cost

·         Easy to install

·         Up to 10Mbps capacity

·         Medium immunity form EMI

·         Medium of attenuation

ADVANTAGES COAXIAL CABLE

·         Inexpensive

·         Easy to wire

·         Easy to expand

·         Moderate level of EMI immunity

DISADVANTAGE COAXIAL CABLE

·         Single cable failure can take down an entire network

     

Twisted Pair Cable

The most popular network cabling is Twisted pair. It is light weight, easy to install, inexpensive and support many different types of network. It also supports the speed of 100 mps.Twisted pair cabling is made of pairs of solid or stranded copper twisted along each other. The twists are done to reduce vulnerably to EMI and cross talk. The number of pairs in the cable depends on the type. The copper core is usually 22-AWG or 24-AWG, as measured on the American wire gauge standard. There are two types of twisted pairs cabling :

- Unshielded twisted pair (UTP)

- Shielded twisted pair (STP)

Unshielded twisted pair (UTP)

UTP is more common. It can be either voice grade or data grade depending on the condition. UTP cable normally has an impedance of 100 ohm. UTP cost less than STP and easily available due to its many use. 

Characteristics of UTP

•  low cost
• easy to install
• High speed capacity
• High attenuation
• Effective to EMI
• 100 meter limit

Advantages of UTP

• Easy installation
• Capable of high speed for LAN
• Low cost

Disadvantages of UTP

• Short distance due to attenuation

Shielded twisted pair (STP)

It is similar to UTP but has a mesh shielding that’s protects it from EMI which allows for higher transmission rate.

Characteristics of STP

• Medium cost
• Easy to install
• Higher capacity than UTP
• Higher attenuation, but same as UTP
• Medium immunity from EMI
• 100 meter limit

Advantages of STP:

• Shielded
• Faster than UTP and coaxial

Disadvantages of STP:

• More expensive than UTP and coaxial
• More difficult installation
• High attenuation rate

             

Fiber Optics

Fiber optic cable uses electrical signals to transmit data. It uses light. In fiber optic cable light only moves in one direction for two way communication to take place a second connection must be made between the two devices. It is actually two stands of cable. Each stand is responsible for one direction of communication. A laser at one device sends pulse of light through this cable to other device. These pulses translated into “1’s” and “0’s” at the other end.

In the center of fiber cable is a glass stand or core. The light from the laser moves through this glass to the other device around the internal core is a reflective material known as cladding. No light escapes the glass core because of this reflective cladding.

Fiber optic cable has bandwidth more than 2 gbps (Gigabytes per Second)

Characteristics Of Fiber Optic Cable:

·         Expensive

·         Very hard to install

·         Capable of extremely high speed

·         Extremely low attenuation

·         No EMI interference

Advantages Of Fiber Optic Cable:

·         Fast

·         Low attenuation

·         No EMI interference

Disadvantages Fiber Optics:

·         Very costly

·         Hard to install 

  

                         

UNBOUNDED/UNGUIDED MEDIA

Unguided media relates to data transmission through the air and is commonly referred to as wireless. The transmission and reception of data is carried out using antenna.

There are two main ways that antenna work:

• Directional (in a beam)
• Omnidirectional (all around)

2.0 Communication Devices

A communication device is a peripherical used for communication between the computers and other devices. Modem is a popular communication device which is normally used for internet communication. Infra red, Bluetooth and LAN card are the examples of communication devices.

Modem

The Modem is a hardware device that enables a computer to send and receive information over telephone lines by converting the digital data used by your computer into an analog signal used on phone lines and then converting it back once received on the other end. In the below picture, is an example of an internal expansion card modem.Modems are referred to as an asynchronous device, meaning that the device transmits data in an intermittent stream of small packets. Once received, the receiving system then takes the data in the packets and reassembles it into a form the computer can use.

                                       

Infrared

Definition: Infrared technology allows computing devices to communicate via short-range wireless signals. With infrared, computers can transfer files and other digital data bidirectionally. The infrared transmission technology used in computers is similar to that used in consumer product remote control units.

nstallation and Usage - Computer infrared network adapters both transmit and receive data through ports on the rear or side of a device. Infrared adapters are installed in many laptops and handheld personal devices. In Microsoft Windows, infrared connections can be created through the same method as other local area network connections. Infrared networks were designed to suppport direct two-computer connections only, created temporarily as the need arises. However, extensions to infrared technology also support more than two computers and semi-permanent 

Performance - Infrared technology used in local networks exists in three different forms:

• IrDA-SIR (slow speed) infrared supporting data rates up to 115 Kbps
• IrDA-MIR (medium speed) infrared supporting data rates up to 1.15 Mbps
• IrDA-FIR (fast speed) infrared supporting data rates up to 4 Mbps

Bluetooth

Definition: Bluetooth is a specification (IEEE 802.15.1) for the use of low-power radio communications to link phones, computers and other network devices over short distances without wires. Bluetooth technology was designed primarily to support simple wireless networking of personal consumer devices and peripherals, including cell phones, PDAs, and wireless headsets. Wireless signals transmitted with Bluetooth cover short distances, typically up to 30 feet (10 meters). Bluetooth devices generally communicate at less than 1 Mbps.

Bluetooth networks feature a dynamic topology called a piconet or PAN. Piconets contain a minimum of two and a maximum of eight Bluetooth peer devices. Devices communicate using protocols that are part of the Bluetooth Specification. Definitions for multiple versions of the Bluetooth specification exist including versions 1.1, 1.2 and 2.0.