Friday, 10 May 2013

Information Technology

Q. 1 Draw and explain the block diagram of computer.
A computer can process data, pictures, sound and graphics. They can solve highly complicated problems quickly and accurately. A computer as shown in Fig.  performs basically five major computer operations or functions irrespective of their size and make. These are
 
 
1) it accepts data or instructions by way of input,
2) it stores data,
3) it can process data as required by the user,
4) it gives results in the form of output, and
5) it controls all operations inside a computer.
We discuss below each of these Computer operations
Q. 2 Explain generations of computer.
Ans.
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. A magnetic drum,also referred to as drum, is a metal cylinder coated with magnetic iron-oxide material on which data and programs can be stored. Magnetic drums were once use das a primary storage device but have since been implemented as auxiliary storage devices.

Transistors replaced vacuum tubes and ushered in the second generation computer. Transistor is a device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today's latest microprocessor contains tens of millions of microscopic transistors.



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.







Fourth Generation - 1971-Present: Microprocessors
The microprocessor brought the fourth generation of computers, as thousands of integrated circuits we rebuilt onto a single silicon chip. A silicon chip that contains a CPU. In the world of personal computers,the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor. Microprocessors also control the logic of almost all digital devices, from clock radios to fuel-injection systems for automobiles.


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.
Artificial Intelligence is the branch of computer science concerned with making computers behave like humans. The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology. Artificial intelligence includes:

Q. 3 what is the difference between Impact and Non impact printer? Give one example of each.
Ans. non-impact printers are quieter and produce better quality print than impact printers.
non-impact printers, the characters and images are form without any direct physical contact of the paper.
impact printers are noisily because of the hitting activity.
and non-impact printers are usually more expensive than impact printers.
In non-impact printers the text or image is formed without any physical contact of the paper and the printer head. But in impact printers the paper and the printer head come in contact and hence the text or image is formed.
Q. 4 Differentiate between RAM and ROM
Ans. Random Access Memory is a form of memory that can be read without having to begin at the first address, then the second address, then the third, and so on. This is a carryover from when most memory was Serial Access, such as magnetic tape, paper tape, or punched cards. The on-board memory computers use for temporary storage is Random Access Memory, but on chips, instead of a hard disc drive.
Read Only Memory is exactly what the name implies, it can only be read, not written to. A CD-ROM is a form of memory, as is a chip on the motherboard which is used to store instructions for the Central Processor Unit. RAM is your computer's temporary storage space. RAM is really the computer's short-term memory. As such, it remembers everything that the computer needs to process the data into information, such as data that has been entered and software instructions, but only when the computer is on. This means that RAM is an example of volatile storage. When the power is off, the data stored in RAM is cleared out. This is why, in addition to RAM, systems always include nonvolatile storage devices for permanent storage of instructions and data when the computer is powered off. Hard disks provide the greatest nonvolatile storage capacity in the computer system.

Q. 5 Define Operating System. Why it is necessary for a computer?
Ans.
An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. The operating system is a vital component of the system software in a computer system. Application programs usually require an operating system to function.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting for cost allocation of processor time, mass storage, printing, and other resources.