Computer Components

Computer components: 

Input
An input device is any hardware device that sends data to the computer, without any input devices, a computer would only be a display device and not allow users to interact with it, much like a TV. In the picture to the right, is a Logitech trackball mouse and an example of an input device. Below is a complete listing of all the different computer input devices that can be used on a computer.
Examples: keyboard, webcam, microphones and etc.

Output
Any peripheral that receives or displays output from a computer. In the picture to the right, is an inkjet printer and a good example of an output device that can make a hard copy of anything on a computer. Below is a listing of all the different computer output devices found on a computer.
Examples: speaker, headphone, monitor and etc.

Storage
A term used to describe any location where information can be held permanently or temporarily for later use. A computer commonly has two storage types: internal and external. For example, an internal storage is a device such as a hard drive and an external removable storage is a device such as a floppy disk drive. Below are examples of forms of storage used on a computer.

• Primary storage:  Alternatively referred to as internal memory and main memory,primary storage is a storage location that holds memory for short periods of times while the computer running. For example, computer RAM and cache are both examples of a primary storage device. This storage is the fastest memory in your computer and is used to store data while it's being used. For example, when you open a program data is moved from the secondary storage into the primary storage.
• Secondary storage:  Alternatively referred to as external memory and auxiliary storage,secondary storage is a storage medium that holds information until it is deleted or overwritten regardless if the computer has power. For example, a floppy disk drive and hard drive are both good examples of secondary storage devices. As can be seen by the below picture there are three different storage on a computer, although primary storage is accessed much faster than secondary storage because of the price and size limitations secondary storage is used with today's computers to store all your programs and your personal data.

Computer of Classification

Personal Computers (PCs)

The most popular PCs are desktop machines. Early PCs had Intel 8088 microprocessors as their CPU. Currently (2004), Intel Dual Core is the most popular processor. The machines made by IBM are called IBM PCs. Other manufacturers use IBM’s specifications and design their own PCs. They are known as IBM compatible PCs. IBM PCs mostly use MS-Windows, WINDOWS –XP or GNU/Linux as Operating System. IBM PCs, nowadays (2004) have 64 to 256 MB main memory, 40 to 80 GB of Hard Disk and a floppy disk or flash ROM. Besides these a 650 MB CDROM is also provided in PCs intended for multimedia use. Another company called Apple also makes pCs. Apple PCs are known as Apple Macintosh. They use Apple’s proprietary OS, which is designed for simplicity of use. Apple Macintosh machines used Motorola 68030 microprocessors but now use Power PC 603 processor. IBM PCs are today the most popular computers with millions of them in use throughout the world.

Workstations

Workstations are also desktop machines. They are, however, more powerful providing processorspeeds about 10 times that of PCs. Most workstations have a large colour video display unit (19 inch monitors). Normally they have main memory of around 256 MB to 4 GB and Hard Disk of 80 to 320 GB. Workstations normally use RISC processors such as MIPS (SIG), RIOS (IBM), SPARC (SUN), or PA-RISC (HP). Some manufacturers of Workstations are Silicon Graphics (SIG), IBM, SUN Microsystems and Hewlett Packard (HP). The standard Operating System of Workstations is UNIX and its derivatives such as AIX (IBM), Solaris (SUN), and HP-UX (HP). Very good graphics facilities and large video screens are provided by most Workstations. A system called X WINDOWS is provided by Workstations to display the status of multiple processes during their execution. Most Workstations have built-in hardware to connect to a Local Area Network (LAN). Workstations are used for executing numeric and graphic intensive applications such as those, which arise in Computer Aided Design, simulation of complex systems and visualizing the results of simulation.

Mainframes Computers

There are organizations such as banks and insurance companies process large number of transactions on-line. They require computers with very large disks to store several Terabytes of data and transfer data from disk to main memory at several hundred Megabytes/sec. The processing power needed from such computers is hundred million transactions per second. These computers are much bigger and faster than workstations and several hundred times more expensive. They normally use proprietary operating systems, which usually provide high expensive services such as user accounting, file security and control. They are normally much more reliable when compared to Operating System on PCs. These types of computers are called mainframes. These are a few manufacturers of mainframes (e.g., IBM and Hitachi). The number of mainframe users has reduced as many organizations are rewriting their systems to use networks of powerful workstations.

Supercomputers

Supercomputers are the fastest computers available at any given time and are normally used to solve problems, which require intensive numerical computations. Examples of such problems are numerical weather prediction, designing supersonic aircrafts, design of drugs and modeling complex molecules. All of these problems require around 10^16calculations to be performed. These problems will be solved in about 3 hours by a computer, which can carry out a trillion floating point calculations per second. Such a computer is classifieds as supercomputer today (2004). By about the year 2006 computers which can carry out 10^15 floating point operations per second on 64 bit floating point numbers would be available and would be the ones which be called supercomputers. Interconnecting several high speed computers and programming them to work cooperatively to solve problems build supercomputers. Recently applications of supercomputers have expanded beyond scientific computing, they are now used to analyze large commercial database, produced animated movies and play games such as chess.Besides arithmetic speed, a computer to be classified as a supercomputer should have a large main memory of around 16 GB and a secondary memory of 1000 GB. The speed of transfer of data from secondary memory to the main memory should be at least a tenth of the memory to CPU data transfer speed. All supercomputers use parallelism to achieve their speed. In Sec. 12.9 we discuss the organization of parallel computers

Minicomputer

The word "minicomputer" (colloquially, "mini") is a term for a class of smaller computersthat evolved in the mid-1960s and sold for much less than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, the New York Timessuggested a consensus definition of a minicomputer as a machine costing less than $25,000, with an input-output device such as a teleprinter and at least 4K words of memory, that is capable of running programs in a higher level language, such as Fortran or Basic.The class formed a distinct group with its own hardware architectures and operating systems.

When single-chip CPUs appeared, beginning with the Intel 4004 in 1971, the term "minicomputer" came to mean a machine that lies in the middle range of the computing spectrum, in between the smallest mainframe computers and the microcomputers. The term "minicomputer" is little used today; the contemporary term for this class of system is "midrange computer", such as the higher-end SPARC, POWER and Itanium-based systems from Oracle, IBM and Hewlett-Packard.

What is Computer Network?

•         A computer network, often simply referred to as a network, is a collection of computers and other hardware components interconnected by communication channels that allow sharing of resources and information.Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network. Simply, more than one computer interconnected through a communication medium for information interchange is called a computer network.
•         Networks may be classified according to a wide variety of characteristics, such as the medium used to transport the data, communications protocol used, scale, topology, and organizational scope.
•         Communications protocols define the rules and data formats for exchanging information in a computer network, and provide the basis for network programming. Well-known communications protocols include Ethernet, a hardware and link layer standard that is ubiquitous in local area networks, and the Internet protocol suite, which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, as well as host-to-host data transfer, and application-specific data transmission formats.
•    Computer networking is sometimes considered a sub-discipline of electrical engineering, telecommunications, computer science, information technology or computer engineering, since it relies upon the theoretical and practical application of these disciplines.

How is Computer work?

Computer Basics

To accomplish a task using a computer, you need a combination of hardware, software, and input.

Hardware consists of devices, like the computer itself, the monitor, keyboard, printer, mouse and speakers. Inside your computer there are more bits of hardware, including the motherboard, where you would find the main processing chips that make up the central processing unit (CPU). The hardware processes the commands it receives from the software, and performs tasks or calculations.

Software is the name given to the programs that you install on the computer to perform certain types of activities. There is operating system software, such as the Apple OS for a Macintosh, or Windows 95 or Windows 98 for a PC. There is also application software, like the games we play or the tools we use to compose letters or do math problems.

You provide the input. When you type a command or click on an icon, you are telling the computer what to do. That is called input.

How They Work Together

First, you provide input when you turn on the computer. Then the system software tells the CPU to start up certain programs and to turn on some hardware devices so that they are ready for more input from you. This whole process is called booting up.

The next step happens when you choose a program you want to use. You click on the icon or enter a command to start the program. Let's use the example of anInternet browser. Once the program has started, it is ready for your instructions. You either enter an address (called a URL,which stands for Uniform Resource Locator), or click on an address you've saved already. In either case, the computer now knows what you want it to do. The browser software then goes out to find that address, starting up other hardware devices, such as a modem, when it needs them. If it is able to find the correct address, the browser will then tell your computer to send the information from the web page over the phone wire or cable to your computer. Eventually, you see the web site you were looking for.

If you decide you want to print the page, you click on the printer icon. Again, you have provided input to tell the computer what to do. The browser software determines whether you have a printer attached to your computer, and whether it is turned on. It may remind you to turn on the printer, then send the information about the web page from your computer over the cable to the printer, where it is printed out. 

Computer System

What is computer system?

 Computer system is a system of interconnected computers that share a central storage system and various peripheral devices such as a printers, scanners, or routers. Each computer connected to the system can operate independently, but has the ability to communicate with other external devices and computers.

Computer History and Generations

First Generation : Vacuum Tubes (1940-1956)

•The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms.

•The UNIVAC and ENIAC computers are examples of first-generation computing devices.

    

Second Generation: Transistors (1956-1963)

•       The invention of Transistors marked the start of the second generation. These transistors took place of the vacuum tubes used in the first generation computers. 

•        First large scale machines were made using these technologies to meet the requirements of atomic energy laboratories. One of the other benefits to the programming group was that the second generation replaced Machine language with the assembly language. Even though complex in itself Assemly language was much easier than the binary code.

•         Second generation computers also started showing the characteristics of modern day computers with utilities such as printers, disk storage and operating systems. Many financial information was processed using these computers. 

  

Third Generation: Intergrated Circuits (1964-1971)

• Although transistors were great deal of improvement over the vacuum tubes, they generated heat and damaged the sensitive areas of the computer. The Intergreated Circuit(IC) was invented in 1958 by Jack Kilby. It combined electronic components onto a small silicon disc, made from quartz. 

• More advancement made possible the fitings of even more components on a small chip or a semi conductor. Also in third generation computers, the operating systems allowed the machines to run many different applications. These applications were monitored and coordinated by the computer's memory.
  
  
  
  
  
  
  
  
  
  Fourth Generation: Microprocessor (1971 - present)

  
  

  • Fourth Generation computers are the modern day computers. The Size started to go down with the improvement in the integerated circuits. Very Large Scale(VLSI) and Ultra Large scale(ULSI) ensured that millions of components could be fit into a small chip. It reduced the size and price of the computers at the same time increasing power, efficiency and reliability. "The Intel 4004 chip, developed in 1971, took the integrated circuit one step further by locating all the components of a computer (central processing unit, memory, and input and output controls) on a minuscule chip." 
    
    

  • Due to the reduction of cost and the availability of the computers power at a small place allowed everyday user to benefit. First came the minicomputers, which offered users different applications, most famous of these the word processors and spreadsheets, which could be used by non-technical users. Video game systems like Atari 2600 generated the interest of general populace in the computers. 

  
  

  • In 1981, IBM introduced personal computers for home and office use. "The number of personal computers in use more than doubled from 2 million in 1981 to 5.5 million in 1982. Ten years later, 65 million PCs were being used." Computer size kept getting reduced during the years. It went down from Desktop to laptops to Palmtops. Machintosh introduecd Graphic User Interface in which the users didnt' have to type instructions but could use Mouse for the purpose. 

  
  

  • The continued improvement allowed the networking of computers for the sharing of data. Local Area Networks(LAN) and Wide Area Network(WAN), were potential benefits, in that they could be implemented in corporations and everybody could share data over it. Soon the internet aand World Wide Web appeared on the computer scene and formented the Hi-Tech revolution of 90's. 

   

  

   

   

   

   

   Fifth Generation : Artificial Intelligence (Present and beyond)

  
  

  • Fifth generations computers are only in the minds of advance research scientiets and being tested out in the laboratories. These computers will be under Artifical Intelligence(AI), They will be able to take commands in a audio visual way and carry out instructions. Many of the operations which requires low human intelligence will be perfomed by these computers.

  • Parallel Processing is coming and showing the possibiliy that the power of many CPU's can be used side by side, and computers will be more powerful than thoes under central processing. Advances in Super Conductor technology will greatly improve the speed of information traffic. Future looks bright for the computers.