DATA REPRESENTATION

 

DATA REPRESENTATION

Very Short answer Type Questions

Q.1       Add the binary numbers (a) 110101 and 101111                                   (b) 10110 and 1101

Ans: (a) 1100100              (b) 100011

Q.2     Convert 11111011110101₂ to octal.

Ans: 37365

Q.3    Covert  the following binary numbers to decimal  - 

           (a)1010                   (b) 111000        (c) 10101111               (d) 10110

Ans: (a) 10             (b) 56           (c) 175                                                  (d) 22

Q.4 Covert  the following Decimal numbers to binary  - 

           (a) 23                      (b) 100                    (c) 161                     (d) 145

Ans: (a) 10111                  (b) 1100100                      (c) 10100001  (d) 10010001

Q.5         Covert  the following Hexadecimal numbers to Binary  - 

           (a) BE                      (b) BC9                    (c) A07                   (d) 7AB4

Ans: (a)10111110          (b) 101111001001 (c) 101000000111 (d) 0111101010110100

Q.6    Covert  the following binary numbers to Hexadecimal  - 

           (a)101000001        (b) 11100011                                            (c) 10101111                                           (d) 101101111

Ans: (a) 141                      (b) E3                                                   (c) AF                                                  (d)16F

Q.7 Covert  the following Octal numbers to Binary - 

           (a) 456                    (b) 26                       (c) 751                                   (d) 777

Ans: (a) 100101110           (b) 010110                                         (c) 111101001                                       (d)111111111

Q.8     Convert the following:

           (a) 446₈ to (           )₁₆          (b) 47.5₈ to (      )₁₀          (c) 45.9₁₀ to (           )₂ Ans:  (a) 126                           (b) 39.625                              (c) 101101.1110

 

Short Answer Type Questions  Q.1 What is the use of encoding schemes?

Ans: A character encoding provides a key to unlock (ie. crack) the code. It is a set of mappings between the bytes in the computer and the characters in the character set. Without the key, the data looks like garbage.

 So, when you input text using a keyboard or in some other way, the character encoding maps characters you choose to specific bytes in computer memory, and then to display the text it reads the bytes back into characters. Unfortunately, there are many different character sets and character encodings, ie. many different ways of mapping between bytes, code points and characters. The section Additional information provides a little more detail for those who are interested.

Q.2     Discuss UTF-8 encoding Scheme.

Ans: UTF-8 is a compromise character encoding that can be as compact as ASCII (if the file is just plain English text) but can also contain any unicode characters (with some increase in file size). UTF stands for Unicode Transformation Format. The '8' means it uses 8-bit blocks to represent a character.

Q.3   How UTF-8 encoding scheme different from UTF-32 encoding scheme?

Ans: UTF-8: Variable-width encoding, backwards compatible with ASCII. ASCII characters (U+0000 to U+007F) take 1 byte, code points U+0080 to U+07FF take 2 bytes, code points U+0800 to U+FFFF take 3 bytes, code points U+10000 to U+10FFFF take 4 bytes. Good for English text, not so good for Asian text.

UTF-32 uses 32-bit values for each character. That allows them to use a fixed-width code for every character. UTF-32 is opposite, it uses the most memory (each character is a fixed 4 bytes wide), but on the other hand, you know that every character has this precise length, so string manipulation becomes far simpler. You can compute the number of characters in a string simply from the length in bytes of the string. You can't do that with UTF-8. Q.4 What are ASCII and extended ASCII schemes?

Ans: The standard ASCII character set uses just 7 bits for each character. There are several larger character sets that use 8 bits, which gives them 128 additional characters. The extra characters are used to represent non-English characters, graphics symbols, and mathematical symbols.

 The extended ASCII character set uses 8 bits, which gives it an additional 128 characters. The extra characters represent characters from foreign languages and special symbols for drawing pictures.

Q.5      What is the utility of ISCII encoding schemes?

ISCII is a bilingual character encoding (not glyphs) scheme. Roman characters and punctuation marks as defined in the standard lower-ASCII take up the first half the character set (first 128 slots). Characters for indie languages are allocated to the upper slots (128-255). T Q.6 What is Unicode? What is its significance?

Ans: Unicode is a character encoding standard that has widespread acceptance. Microsoft software

uses Unicode at its core. Whether you realize it or not, you are using Unicode already! Basically, ―computers just deal with numbers. They store letters and other characters by assigning a number for each one. Before Unicode was invented, there were hundreds of different encoding systems for assigning these numbers. No single encoding could contain enough characters.1‖ This has been the problem we, in SIL, have often run into. If you are using a legacy encoding your font conflicts with the font someone in another area of the world uses. You might have an  in your font while someplace else someone used a  at the same codepoint. Your files are incompatible. Unicode provides a unique number for every character and so you do not have this problem if you use Unicode. If your document calls for U+0289  it will be clear to any computer program what the character should be

Q.7       What are ASCII and ISCII? Why are these used?

Ans: ASCII uses a 7-bit encoding and ISCII uses an 8-bit which is an extension of ASCII. These are encoding schemes to represent character set in s computer system.

Q.8  Compare UTF-8 and UTF-32 encoding schemes. Which one is most popular scheme?

Ans: UTF-8: Variable-width encoding, backwards compatible with ASCII. ASCII characters (U+0000 to U+007F) take 1 byte, code points U+0080 to U+07FF take 2 bytes, code points U+0800 to U+FFFF take 3 bytes, code points U+10000 to U+10FFFF take 4 bytes. Good for English text, not so good for Asian text.

UTF-32 uses 32-bit values for each character. That allows them to use a fixed-width code for every character. UTF-32 is opposite, it uses the most memory (each character is a fixed 4 bytes wide), but on the other hand, you know that every character has this precise length, so string manipulation becomes far simpler. You can compute the number of characters in a string simply from the length in bytes of the string. You can't do that with UTF-8. Q.9 What do you understand by code point and code unit?

Ans: A code point is the atomic unit of information. ... Each code point is a number which is given meaning by the Unicode standard. A code unit is the unit of storage of a part of an encoded code point. In UTF-8 this means 8-bits, in UTF-16 this means 16-bits. Q.10 What is code space? How is it related to code point?

Ans: In computing, Code space may refer to: In memory address space: code space, where machine code is stored. For a character encoding: code space (or code space), the range of code points.