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33 - Error Checking and Correction

 1. With the huge amounts of 1s and 0s being transmitted along cables, even with representing a simple text document errors can occur.

  FALSE

  TRUE

 2. Errors can arise from ______________________ usually in the form of electrical noise.

  virus attacks

  hacking attempts

  DDOS attacks

  interference on a network

 3. The end result (when errors occur) is that certain bits get corrupted. This means, for example, that some _______________

  bits explode and fail to send

  some binary sequences duplicate themselves by a factor of million

  several bits double themselves to produce a greater number

  binary 0's get turned into binary 1's

 4. Normal ASCII characters do not make use of the MSB storing the letter in 7 bits. This leaves us one left over or unused bit, which can be put to good use when turned into a ______________

  parity bit

  minority bit

  majority voting bit

  least significant bit

 5. This is a crude method of identifying errors in data by transmitting binary digits multiple times and then looking at the pattern received.

  check sums

  majority voting

  check digits

  parity bit checking

 6. This is a form of redundancy checking used for error detection on identification numbers, such as bank account numbers (where at least sometimes the input is manual)

  check digits

  parity bit checking

  check sums

  majority voting

 7. The ISBN-10 number system used for books makes use of a process called Modulo-11 to create its _______________

  check digits

  majority voting

  check sums

  parity bit checking

 8. This is a mathematical algorithm applied to a block of data. The data from the block is used in order to create the initial __________. 
The initial ___________ is then added and transmitted along with the original data.

  check sum

  check digit

  parity bit

  majority vote

 9. If the checksums match (assuming the same algorithm has been applied at both ends) then the ___________________-

  error is set to 1 (e.g. an error has occurred in transmission)

  the data has most likely been transmitted correctly

  the data has failed to arrive

  the data has an error (but only in transmission) which suggests packet errors

 10. In computer processors the parity flag indicates if the number of set bits is odd or even in the binary representation of the result of the last operation. It is normally a ____________

  8 bit (byte) in a processor control unit

   single bit in a processor status register

  None of the above

  double bit (for double precision)


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