1 Lecture Notes for This WeekIndex

1.1 From the Class Notes link on the Course Home PageIndex

120_CharacterEncoding.html - Character Encoding / Line Ends
- know these Seven Famous ASCII Characters: 0D 0A 20 30 41 61 7F
- do not memorize any EBCDIC
130_big_picture.txt - The Big Picture on Bit Patterns
140_attack.txt - Remote Attack Script uses hexadecimal obfuscation
145_textbook_secrets.txt - Alcatel-Lucent Traning Manual containing secret messages in hexadecimal
200_DEBUGbasics.html
200_DEBUGhelp.txt

1.1.1 AssignmentsIndex

Assignment #06 - midterm corrections.

1.2 From Blackboard Course DocumentsIndex

These documents have restricted distribution and cannot be put on the Course Home Page.

02.ppt - Data Representation
- Character encoding: ASCII, Unicode, Line Endings
06.ppt - Memory
- see memory speeds on slide 7
- ignore slides 12-34, 37
- see memory types, memory hierarchy (speeds), cache, virtual memory
- omit the rest of this slide set
03.ppt - Boolean Algebra and Digital Logic
- ignore Digital Logic and slides 19-73, 75-76
- Boolean Algebra

1.3 From the InternetIndex

http://en.wikipedia.org/wiki/American_Standard_Code_for_Information_Interchange
http://en.wikipedia.org/wiki/Latin-1
http://en.wikipedia.org/wiki/Unicode
http://en.wikipedia.org/wiki/UTF-8
http://en.wikipedia.org/wiki/ISO/IEC_8859 - a joint ISO and IEC series of standards for 8-bit character encodings
http://czyborra.com/charsets/iso8859.html - The ISO 8859 Alphabet Soup
http://en.wikipedia.org/wiki/UTF-8
http://en.wikipedia.org/wiki/Bitwise_operation
http://download.oracle.com/javase/tutorial/java/nutsandbolts/op3.html - Bitwise Operators in Java
http://en.wikipedia.org/wiki/Introduction_to_Boolean_algebra
http://en.wikipedia.org/wiki/Parity_bit

1.4 From the Classroom Whiteboard/ChalkboardIndex

Your in-class notes go here.

1.4.1 Character EncodingIndex

Character codes: ASCII, extended ASCII, EBCDIC, Unicode, UTF-8
- ASCII Control Characters (unprintable)
- line ends for text files on Unix/Mac/Windows
- reading character tables
- compare ASCII & EBCDIC for sort order and common printable characters
- ASCII puts ‘A’ before ‘a’; EBCDIC does the reverse
- tabs vs. spaces
- know the Seven Famous ASCII Characters
  - 0D 0A 20 30 41 61 7F
- do not memorize any EBCDIC
- how to print the decimal value of 00001111(2) on the screen in ASCII?
  - decimal value is 15: send 31h and 35h (“1” and “5”)
Problems with all the 8-bit extended-ASCII character sets
- can’t have Latin1 French and Latin2 Polish in the same text file: why?
UTF-8 advantages and disadvantages
- same as ASCII, no endian-ness, multi-byte, full Unicode, may require more bytes than Unicode due to encoding scheme
Fonts vs. Character codes
- codes only say what letter, not what it looks like
Why can’t French (Latin1) and Polish (Latin2) exist in the same text file?
- same problem for all the 8-bit extended-ASCII character sets
How many ASCII characters are there?
What is the difference between ‘A’ and ‘a’? ‘M’ and ‘m’? ‘Z’ and ‘z’?
How many ASCII control characters (unprintable) are there?
- what are their hex values?

1.4.2 Boolean Algebra / Bitwise OperatorsIndex

Shifting numbers right and left
- shifiting effect on two’s complement numbers: does it work?
- Arithmetic Right Shift vs. Logical Right Shift
  - duplicate the top (carry) bit for Arithmetic Right Shift
- F4240h = 1,000,000(10)
  - so F42400h = 1,000,000 * 16 = 16,000,000
  - so F424h = 1,000,000/16 = 1000000 * 0.0625 = 100 * 625 = 62,500
- 03641100(8) = 1,000,000(10)
  - so 036411000 = 1,000,000 * 8 = 8,000,000
- 1010(2) = 10 decimal
  - so 101000(2) = 10 * 2 * 2 = 40 decimal
Bitwise Operators AND, OR, XOR, NOT (in Java: & | ^ ~)
- don’t confuse bitwise with logical: & with &&, | with ||, or ~ with !
- if x=1, y=2 then x&y = 0 (no bits in common)
- if x=6, y=12 then x&y = 4 (one bit in common)
- XOR is Exclusive OR - A or B but not both
  - true OR true is true
  - true XOR true is false
- if a=6,b=3 what is a&b? what is a|b? what is a^b? what is ~a?
- if a=5,b=10 what is a&b? what is a|b? what is a^b? what is ~a?
Note: All integer types in Java are signed (except char)!
- see http://www.javamex.com/java_equivalents/unsigned.shtml
- Java has a special unsigned (“logical”) right shift operator: >>>
- need to use bit masking for unsigned arithmetic
Conversions between upper/lower in ASCII using bitwise OR and AND:
- 'A' | ' ' = 'a' (OR turns on the 20h bit, making it lower-case)
- 'a' & ~' ' = 'A' (AND turns off the 20h bit, making it upper-case)
ASCII parity bit, used to detect errors in data transmission
- is ‘A’ even or odd parity? convert it to even parity, then to odd
- is CR even or odd parity? convert it to even parity, then to odd
Simplifying complex logic using Boolen Algebra - identities - deMorgan
1. simplify: if ((x < y) && (y < z)) || ((x < y) && (y >=z ))
  - simplifies to just if (x < y) because:
  - let a = (x<y) and b = (y<z), therefore b' = (y>=z)
  - rewrite ab+ab' = a(b+b') = a(1) = a = (x<y)
2. suppose a stale order means: date > 120 and amount > 0
  1. simplify: print unless stale
    - unless stale means if NOT stale
    - print if NOT (date > 120 && amt > 0)
    - using deMorgan: print if (date <= 120 || amt <= 0)
  2. simplify: print unless (stale and amt < 0)
    - print if NOT (stale && amt < 0)
    - print if ( !stale || amt >= 0)
    - print if ( date <= 120 || amt <= 0 || amt >= 0)
    - print if ( date <= 120 || TRUE )
    - therefore: always print (probably an error in the specifications!)
3. Show that (xy + x'z + yz')' = y'(x+z')
  - (x'+y')(x+z')(y'+z) -- deMorgan
  - (x'x + x'z' + xy' + y'z')(y'+z) -- expand first two expressions
  - ( 0 + x'z' + xy' + y'z')(y'+z) -- identities
  - x'y'z' + x'z'z + xy'y' + xy'z + y'y'z' + y'z'z -- expand again
  - x'y'z' + 0 + xy' + xy'z + y'z' + 0 -- identities
  - x'y'z' + y'z' + xy' + xy'z -- regroup similar terms
  - y'z' + xy' -- absorption rule
  - y'(x+z') -- QED

2 Midterm Test #1 - 15%Index

Midterm Test One Results: 100 96.7 96.7 93.3 93.3 93.3 90 90 86.7 83.3 83.3 79.2 76.7 76.7 76.7 76.7 76.7 76.7 76.7 73.3 73.3 73.3 73.3 73.3 70 66.7 66.7 66.7 66.7 66.7 62.7 60 60 60 56.7 56.7 56.1 53.3 53.3 46.7 46.7 46.7 46.7 43.3 42.9 40 33.3 33 30 30 29.7 29.7 26.7 23.3 20 20 13.3
See Assignment #06 - midterm corrections.

3 Self-Mark 03Index

COUNT=36 AVERAGE 2.2 Q1=2.7 Q2=2.6 Q3=2.5 Q4=2.7 Q5=2.1 Q6=2.4 Q7=2.2 Q8=2.6 Q9=2.6 Q10=2.5 Q11=2.3 Q12=2.4 Q13=2.2 Q14=2.4 Q15=2.7 Q16=2.4 Q17=2.2 Q18=2.2 Q19=2.5 Q20=2.6 Q21=2.2 Q22=2.0 Q23=2.1 Q24=2.5 Q25=2.1 Q26=2.4 Q27=2.2 Q28=2.2 Q29=2.1 Q30=2.0 Q31=2.0 Q32=2.3 Q33=2.3 Q34=2.3 Q35=2.1 Q36=1.9 Q37=1.7 Q38=2.2 Q39=2.2 Q40=2.2 Q41=1.6 Q42=2.5 Q43=2.2 Q44=2.2 Q45=2.1 Q46=1.9 Q47=2.2 Q48=1.8 Q49=1.9 Q50=1.9 Q51=1.8 Q52=2.3

4 Self-Mark 04Index

COUNT=40 AVERAGE 2.3 Q1=2.5 Q2=2.5 Q3=2.5 Q4=2.6 Q5=2.6 Q6=2.5 Q7=2.5 Q8=2.6 Q9=2.5 Q10=2.4 Q11=2.6 Q12=2.5 Q13=2.5 Q14=2.6 Q15=2.4 Q16=2.2 Q17=2.4 Q18=2.5 Q19=2.3 Q20=2.4 Q21=2.5 Q22=2.4 Q23=2.2 Q24=2.2 Q25=1.9 Q26=2.0 Q27=2.1 Q28=2.3 Q29=2.4 Q30=2.4 Q31=2.3 Q32=2.3 Q33=2.4 Q34=2.4 Q35=2.4 Q36=2.4 Q37=2.4 Q38=2.0 Q39=2.1 Q40=2.1 Q41=1.8 Q42=1.4 Q43=1.8 Q44=1.9 Q45=1.9 Q46=1.8 Q47=1.7 Q48=1.9

Author: 
| Ian! D. Allen  -  idallen@idallen.ca  -  Ottawa, Ontario, Canada
| Home Page: http://idallen.com/   Contact Improv: http://contactimprov.ca/
| College professor (Free/Libre GNU+Linux) at: http://teaching.idallen.com/
| Defend digital freedom:  http://eff.org/  and have fun:  http://fools.ca/

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