Showing posts with label Class 11. Show all posts
Showing posts with label Class 11. Show all posts

Thursday, July 14, 2011

Unicode vs ASCII


Unicode vs ASCII
Unicode and ASCII both are standards for encoding texts. Uses of such standards are very much important all around the world. Code or standard provides unique number for every symbol no matter which language or program is being used. From big corporation to individual software developers, Unicode and ASCII have significant influence. Communication between different regions in the world was difficult but this was needed in every time. Recent easiness in communication and development of a unique platform for all people in the world is the result of inventing some universal encoding system.
Unicode
Development of Unicode was coordinated by a non-profit organization Unicode Consortium. Unicode is most compatible with different language like Java, XML, Microsoft .Net etc. Symbolic figure or glyptic art are greatly available due to modification of character shape which is done using some mechanism adopted by Unicode. Invention of Unicode has brought major renovation in texture, graphics, themes etc. Natural numbers or electrical pulse is used to convert a text or picture and they are easy to transmit through different networks.
• Recent version of Unicode consist more than 109000 characters, charts for visual reference, encoding methodology, standard for encoding, collation, two-way display, depicting etc.
• UTF-8 is one of the widely used encodings.
• Unicode consortium consists of world leading software and hardware companies like Apple, Microsoft, Sun Microsystems, Yahoo, IBM, Google Oracle Corporation.
• First book was published by the consortium in 1991 and latest Unicode 6.0 published in 2010.
ASCII
Short form of American Standard Code for Information Interchange is ASCII. Encoding of that system is based on ordering the English alphabet. All modern data encoding machines support ASCII as well as other. ASCII was first used by Bell data services as a seven bit Tele-printer. Use of binary system had brought tremendous change in our personal computing. Personal Computer as we see now is the boon of using binary language which was used as core things for encoding and decoding. Various languages later created and adopted are based on it. As binary system makes the PC more comfortable and user friendly for all, similarly ASCII is being used for making easiness in communicating. 33 characters are non-printing, 94 printing characters and space altogether makes 128 characters which are used by ASCII.
• It allows 128 characters.
• WWW or World Wide Web used ASCII as character encoding system but now ASCII is superseded by UTF-8.
• Short passage was encoded by early ASCII.
• ASCII-code order is different from traditional alphabetical order.
Difference between Unicode and ASCII
• Unicode is an expedition of Unicode Consortium to encode every possible languages but ASCII only used for frequent American English encoding. For example, ASCII does not use symbol of pound or umlaut.
• Unicode require more space than ASCII.
• Unicode use 8, 16 or 32 bit characters based on different presentation while ASCII is seven-bit encoding formula.
• Many software and email can’t understand few Unicode character set.
• ASCII only supports 128 characters while Unicode supports much more characters.
Though different variations appear among Unicode and ASCII but both are very much essential in development of web based communication.

ASCII


ASCII
Short form of American Standard Code for Information Interchange is ASCII. Encoding of that system is based on ordering the English alphabet. All modern data encoding machines support ASCII as well as other. ASCII was first used by Bell data services as a seven bit Tele-printer. Use of binary system had brought tremendous change in our personal computing. Personal Computer as we see now is the boon of using binary language which was used as core things for encoding and decoding. Various languages later created and adopted are based on it. As binary system makes the PC more comfortable and user friendly for all, similarly ASCII is being used for making easiness in communicating. 33 characters are non-printing, 94 printing characters and space altogether makes 128 characters which are used by ASCII.
• It allows 128 characters.
• WWW or World Wide Web used ASCII as character encoding system but now ASCII is superseded by UTF-8.
• Short passage was encoded by early ASCII.
ASCII-code order is different from traditional alphabetical order.
Difference between Unicode and ASCII
• Unicode is an expedition of Unicode Consortium to encode every possible languages but ASCII only used for frequent American English encoding. For example, ASCII does not use symbol of pound or umlaut.
• Unicode require more space than ASCII.
• Unicode use 8, 16 or 32 bit characters based on different presentation while ASCII is seven-bit encoding formula.
• Many software and email can’t understand few Unicode character set.
• ASCII only supports 128 characters while Unicode supports much more characters.
Though different variations appear among Unicode and ASCII but both are very much essential in development of web based communication.

Compiler vs Interpreter


Compiler and interpreter, both basically serve the same purpose. They convert one level of language to another level. A compiler converts the high level instructions into machine language while an interpreter converts the high level instruction into some intermediate form and after that, the instruction is executed.
Compiler
A compiler is defined as a computer program that is used to convert high level instructions or language into a form that can be understood by the computer. Since computer can understand only in binary numbers so a compiler is used to fill the gap otherwise it would have been difficult for a human to find info in the 0 and 1 form.
Earlier the compilers were simple programs which were used to convert symbols into bits. The programs were also very simple and they contained a series of steps translated by hand into the data. However, this was a very time consuming process. So, some parts were programmed or automated. This formed the first compiler.
More sophisticated compliers are created using the simpler ones. With every new version, more rules added to it and a more natural language environment is created for the human programmer. The complier programs are evolving in this way which improves their ease of use.
There are specific compliers for certain specific languages or tasks. Compliers can be multiple or multistage pass. The first pass can convert the high level language into a language that is closer to computer language. Then the further passes can convert it into final stage for the purpose of execution.
Interpreter
The programs created in high level languages can be executed by using two different ways. The first one is the use of compiler and the other method is to use an interpreter. High level instruction or language is converted into intermediate from by an interpreter. The advantage of using an interpreter is that the high level instruction does not goes through compilation stage which can be a time consuming method. So, by using an interpreter, the high level program is executed directly. That is the reason why some programmers use interpreters while making small sections as this saves time.
Almost all high level programming languages have compilers and interpreters. But some languages like LISP and BASIC are designed in such a way that the programs made using them are executed by an interpreter.
• A complier converts the high level instruction into machine language while an interpreter converts the high level instruction into an intermediate form.
• Before execution, entire program is executed by the compiler whereas after translating the first line, an interpreter then executes it and so on.
• List of errors is created by the compiler after the compilation process while an interpreter stops translating after the first error.
• An independent executable file is created by the compiler whereas interpreter is required by an interpreted program each time.


What is the difference between primary & secondary storage device?


PRIMARY STORAGE DEVICES            SECONDARY STORAGE DEVICES

1.These devices are tempo-      1.These devices are permanent.
rary.                       
2.These devices are expensive.  2.These are cheaper.
3.These devices are faster,     3.These devices Computers via 
therefore expensive.            cables,and slow, therefore 
                                cheaper.
4.These devices have less       4.These devices have high 
storage capacity.               storage capacity.
5.These devices refer to RAM.   5.These devices refer to FDD

Difference between primary and secondary memory.

The primary memory or the main memory is part of the main computer system. The processor or the CPU directly stores and retrieves information from it. This memory is accessed by CPU, in random fashion. That means any location of this memory can be accessed by the CPU to either read information from it, or to store information in it.
o The primary memory itself is implemented by two types of memory technologies. The first is called Random Access Memory (RAM) and the other is read only memory (ROM). A more appropriate name for RAM is RWM (Read Write Memory), the CPU can write and read information from any primary memory location implemented using RAM. The other part of primary memory is implemented using ROM which stands for Read Only Memory.


Primary memory is much faster and also it is more cost effective. But the secondary memory is much slower and also less costly. It stores the data permanently unless it is erased. The secondary memory is usually available in the form of floppy disk storage media, hard disk, CD, DVD, Pen drive (i.e. Mass storage devices), memory chips. A 5 and1/4 inch floppy disk typically stores 1.44 mb of data. The data on the floppy disk is organized in terms of tracks and sectors. Hard disk can have large capacity something like 80-300 GB's or higher. Hard disk itself is made up of, large number of platters. Hard disk is usually much faster compared to floppy disk. CD can store up to 750 mb of data. Information on CD ROM is organized in terms of a spiral track. A DVD is digital Versatile Disk and can store 4.6 Gigabyte of information. All these CD disk are usually write ones and read many times (if the disk is not multisession and re writable). So are the DVDs.


INTRODUCTION TO COMPUTER IX

INTRODUCTION TO COMPUTER

Introduction

A computer is an electronic machine that accepts instruction as input data, stores the data, processes them and produces the desired output. Computer automatically accepts data and instructions as input, stores and processes them and produces and gives the output under the control of the instructions of the stored programs.

Features of computer:

As computer is an intelligent amplifier that performs the above-mentioned operations in a faster, accurate and efficient way, it creates extra leisure time which can be used in matters involving creativity & judgment. Some of the common characteristics possessed by computers are as follows:
  • A computer can perform tasks at very high speed. The speed, with which computers carry out these operations, varies from a few microseconds (10-6 of a second or millionth of a second) to nanoseconds (10-9 of a second or billionth of a second).
  • It can store a large amount of data in its memory forever
  • It gives 100% accurate outputs unless the wrong data and instructions are entered.
  • Once the data and instructions are given, it caries out its operation automatically to produce the desired output.
  • It can perform its tasks repetitively with same speed, efficiency and accuracy, without being affected by traits of tiredness and lack of concentration.
  • It is versatile in a sense that it can perform from simple tasks, such as Desktop Publishing, to advanced tasks, such as controlling of automatic weapons, satellite launching, etc.

Limitations of Computers:

  • Since computer does not have its own intelligence, it should be given instructions to carry out its tasks. However, the fifth generation is supposed to have own intelligence.
  • An important data can be lost sometimes due to the breakdown of storage media in machine.
  • However there are various systems to protect data, but there is always fear of data piracy.
  • Computer is a very expensive to install and maintain that it would be difficult to afford it for everybody. But, with the ever-increasing advances being made in the state of the art, the cost of computer equipment has dropped drastically over the years. Hardware costs have been decreasing at an estimated annual rate of 25%.
  • Computers cannot store data unless they are given instructions.