Character Coding Exam questions

Question 1.

a) How many characters can be represented using ASCII? 128

b) How would the character E be represented using 7 bits? 1000101

c) Characters are transmitted using an e-bit code that includes a parity bit in the most significant bit?

D- 01000100

E- 11000101

H- 01001000




d) Parity works by either using odd or even parity. If there is an odd number of 1s in the end binary parity bit will be a 0. There are 1 bit and 3 bit parity. 1 bit is most common because it requires less data to be sent and is therefore cheaper to implement. At the receiving end, the code can be checked to see whether the number is still odd or even.



Question 2.

a) 53- 0110101

b)0110110

c) 9=57 0=48 difference is 9

d)1

e)3

f)The advantages of majority vote over parity bits is that the majority vote can repair the errors because the data is being sent multiple times where a parity bit can only detect that there is an error.

Character Codes Passport questions

1. What 3 different character systems exist and how many characters does each hold?
Ascii-128 characters, Extended Ascii-256 characters, Unicode-65,536 characters.

2. What are the decimal code equivalent of some letters in the alphabet? what are the Binary versions? a is 97 or 1100001. e is 101 1100101.

3. What are the differences with character codes of capital and lower case letter? They have a decimal difference of 32. The 32 bit is different. 0 is capital 1 is lower case.

4. What is meant by a parity bit? How does Parity work? what different parity systems are there? Parity bit is an extra bit on the end of the information to make sure it is correct and has not been changed. Parity works by either using odd or even parity. so if there is an odd or even number of 1 the end parity bit will be a 1 or 0. There are 1 bit and 3 bit parity. ! bit is most common because it requires less data to be sent and is therefore cheaper to implement.

5. What is meant by a check digit? How does this work? A check digit works by using the rest of the numbers then multiplying them and adding them. Then the check digit is the number between the total and the total rounded up to the nearest 10.

6. What is majority vote? How does it work? Majority vote is when the computer decides whether info is correct by what the majority of that bit is. so the info is sent 3 times and the majority of the 1s or 0s for that bit is what the computer assumes correct.

ISBN Check digit

ISBN Check digit

A ISBN is used to make sure a book code is legal. It is worked out and the check digit is the final digit of the 13 digit combination that makes up the ISBN Code. Here I have an example of my Excel spread sheet that can be used to easily find the check digit and 13 digit code from the first 12 digits. simply input the digits in and it produces the full code at the bottom in orange. You will notice the check digit is in the 13th number column.

Character sets

       

Tasks-Character Coding

1. A) What does ASCII stand for?
        American standard communication information interchange

 B) What is it used for?
      To create a more universal form of coding information mapping the same characters to certain binary numbers.

2. A) How many characters can you have with 7 bit ASCII?

    128

B) What is 8 bit ASCII known as? How many characters can you have with this?
You can have 256 characters

3. What is the ASCII denary character codes for A, C, E?
     A=65  C=67   E=69

4. How do we represent all of the characters from for e.g. Arabic / China?
    We use character set called Unicode.

5. What is meant by Parity?
    It is a technique that checks whether data has been lost or written over when it is moved from one place in storage to another or when it is transmitted between computers.

6. Write your name in ASCII (Binary)
1001010  , 1100001  ,  11001101  ,  1100101  ,  1110011

     J                  a                  m                e                   s

7. What is the letter from the ASCII code 80?   P

8. What is the difference in bit pattern from a capital A to a lower case a?
     The second most important bit determines if it is a capital or lower case.   0=A , 1=a.

9. What is Character Set?

     A set of symbols used to convey information.

Variables and data types

Data type	Description	Sample data
INTEGER	Stores positive or negative whole numbers	17
REAL	Stores numbers that contain decimal places/values and can also store integers	17.65
CHARACTER	Stores a single character which can be a letter, number or symbol	$
STRING	Stores alphanumeric combinations and text. String is really a group of characters stored together as one. Numbers to be used for calculations should not be stored as string data even though they can be. They should be stored as INTEGER or REAL	Batman
BOOLEAN	Stores True or False only. This is sometimes taught as 1 or 0 only where 1 is true and 0 false	True

In a program, data values can be constant or variable. If values are variable they can be changed by the program and the user. When a program is run, the data values are held in memory whilst they are being worked on.

Constants:  Data values that stay the same every time a program is executed are known as constants. Constants are not expected to change.

Variables: are data values that can change when the user is asked a question, for example, their age. Variables may change during program execution.

A variable is a memory location. It has a name that is associated with that location. The memory location is used to hold data. The key difference when comparing a constant to a variable is that the value associated with a variable name may change during program execution. For example 'highScore' would need to be variable to change throughout a game.

Franklin start milestone

Franklin Start Milestone

Six Famous pioneers of Computer Science:

•Tim Berners-Lee.

•Leonard Kleinrock.

•Konrad Zuse.

•Steve Wozniak.

•Ada Lovelace.

•John Atanasoff.

Milestones of development in computing history:

1800s- First works and notes on computer programs. This paved the way for modern computer programs and laid the foundation for computer programming.

First electronic digital computer in the 1930s.

World's first programmable computer. The functional program-controlled Turing-complete Z3 became operational in May 1941.

The first message on the ARPANET was sent by UCLA student programmer Charley 

Kline, at 10:30 p.m, on October 29, 1969. The Advanced Research Projects Agency Network (ARPANET) was an early packet switching network and the first network to implement the protocol suite TCP/IP. Both technologies became the technical foundation of the Internet. ARPANET was initially funded by the Advanced Research Projects Agency (ARPA) of the United States Department of Defense.

World Wide Web is invented in 1989. This allowed information to be transmitted across the globe allowing a new age of communication and information. in March 1990, the first high-speed T1 (1.5 Mbit/s) link between the NSFNET and Europe was installed between Cornell University and CERN, allowing much more robust communications than were capable with satellites. Six months later Tim Berners-Lee would begin writing WorldWideWeb, the first web browser after two years of lobbying CERN management. By Christmas 1990, Berners-Lee had built all the tools necessary for a working Web: the HyperText Transfer Protocol (HTTP) 0.9, the HyperText Markup Language (HTML), the first Web browser (which was also a HTML editor and could access Usenet newsgroups and FTP files), the first HTTP server software (later known as CERN httpd), the first web server(http://info.cern.ch), and the first Web pages that described the project itself. Public commercial use of the Internet began in mid-1989 with the connection of MCI Mail andCompuserve's email capabilities to the 500,000 users of the Internet.


Ada Lovelace- recognised for establishing an early model for a computer. Her notes on the Analytical engine (1840) are now viewed as a description of a computer and software programming. During a nine-month period in 1842–43, Lovelace translated the Italian mathematician Luigi Menabrea's article on Babbage's newest proposed machine, the Analytical Engine. With the article, she appended a set of notes. Explaining the Analytical Engine's function was a difficult task, as even many other scientists did not really grasp the concept and the British establishment was uninterested in it. Lovelace's notes even had to explain how the Analytical Engine differed from the original Difference Engine. Her work was well received at the time; the scientist Michael Faraday described himself as a supporter of her writing.

John Vincent Atanasoff (October 4, 1903 – June 15, 1995) was an American physicist and inventor. He is known for being credited with inventing the first electronic digital computer.

Atanasoff invented the first electronic digital computer in the 1930s at Iowa State College. However there were many challenges to his claim. These were resolved in 1973 when the Honeywell v. Sperry Rand lawsuit ruled that Atanasoff was the inventor of the computer. His special-purpose machine has come to be called the Atanasoff–Berry Computer.

Konrad Zuse (22 June 1910 – 18 December 1995) was a German civil engineer, inventor and computer pioneer. His greatest achievement was the world's first programmable computer. The functional program-controlled Turing-complete Z3 became operational in May 1941. Thanks to this machine and its predecessors, the Z1 and the Z2 Zuse has often been regarded as the inventor of the modern computer.

He founded one of the earliest computer businesses in 1941, producing the Z4, which became the world's first commercial computer. From 1943 to 1945 he designed the first high-level programming language, Plankalkül. In 1969, Zuse suggested the concept of a computation-based universe in his book Rechnender Raum (Calculating Space).

Due to World War II, Zuse's work went largely unnoticed in the United Kingdom and the United States. Possibly his first documented influence on a US company was IBM's option on his patents in 1946.

Leonard Kleinrock (born June 13, 1934) is an American engineer and computer scientist. A computer science professor at UCLA's Henry Samueli School of Engineering and Applied Science, he made several important contributions to the field of computer networking. Most notably in the theoretical foundations of computer networking. He also played an influential role in the development of the ARPANET, the precursor to the Internet, at UCLA.

Sir Timothy John Berners-Lee OM KBE FRS FREng FRSA FBCS (born 8 June 1955), also known as TimBL, is an English computer scientist, best known as the inventor of the World Wide Web.

He made a proposal for an information management system in March 1989, and he implemented the first successful communication between a Hypertext Transfer Protocol (HTTP) client and server via the Internet sometime around mid-November of that same year.

Berners-Lee is the director of the World Wide Web Consortium (W3C), which oversees the continued development of the Web. He is also the founder of the World Wide Web Foundation, and is a senior researcher and holder of the founders chair at the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL).  In 2004, Berners-Lee was knighted by Queen Elizabeth II for his pioneering work. In April 2009, he was elected a foreign associate of the United States National Academy of Sciences. Named in Time magazine's list of the 100 Most Important People of the 20th century, Berners-Lee has received a number of other accolades for his invention.

Stephen Gary "Steve" Wozniak (August 11, 1950) nicknamed "Woz", and sometimes The Wonderful Wizard of Woz, is an American inventor, electronics engineer, programmer, and technology entrepreneur who co-founded Apple Inc. He is known as a pioneer of the personal computer revolution of the 1970s and 1980s, along with Apple co-founder Steve Jobs.

Wozniak single-handedly developed the 1976 Apple I, which was the computer that launched Apple. He primarily designed the 1977 Apple II, while Jobs oversaw the development of its unusual case and Rod Holt developed the unique power supply.