I101 Parity Assignment
Translate each line to a character.(show the result in a way that I
can check it – to the right of the row)
If there is an error, circle the bit that is wrong (or just change its
color). Show the correct character at the right of each row.
You can work on this sheet -- be sure to put your name on it
If you make any extra marks on the page be sure I can tell which ones
count.
Read the material below the table before doing the homework.
EVEN PARITY
010101001
011010001
011001010
001000001
011001100
011011000
011101011
011001100
011000000
011001100
001000001
011100110
011000011
011100111
001000001
010100110
011101000
001001000
011011111
011001100
001000001
010010000
011011110
010010000
010011111
001000010
001010000
We parity check by both rows and columns. That is, for each row the
first eight bits constitute one ASCII character and the ninth (rightmost)
bit is the parity check bit (originally set to zero or one so that the total
number of ones in the row is even)
After every eight rows there is a row that is all parity check for the
columns above. That is, the first (left) bit in the ninth row is a parity
check bit for the eight bits in the COLUNM above it. Obviously you
don't try to convert this row into a character! Finally the last (right) bit in
this row is a check bit for both the row AND column. That is the total
number of ones in the ninth row and the ninth column (taken together) is
made even by this bit.
Remember that this allows you to trace the row with bad parity and the
column with bad parity to identify the exact bit that is wrong (and thus
you can correct it, since it can be only one thing other than what it is.)
Parity Assignment Grading Criteria
Failure to demonstrate understanding of a major point is a reduction of
at least one letter grade.
Inconsistency on a sub-point is a reduction of at least one half a letter
grade.


Students must understand how to convert binary into a character
o understand that upper case and lower case are different
characters
o correctly represent non-letter characters. (space, punctuation)
Students must understand how parity bits are added to character
representations
must not translate parity rows into characters
o must correctly use the parity bits
Students must understand how parity is used to detect and correct
errors.
o differentiate error bits from those that indicate errors
o follow directions for marking errors
o show correct letters
o

Marking:
uc/lc -- you have not made it absolutely clear what case the letter is
uc -- the letter should be upper case
lc -- the letter should be lower case
parity -- incorrect handling of parity check