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Jeffery Johnston
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1 !"#$%&'())*'"+,&-,.-!! 1

2 Thinking about thinking in code George V. Neville-Neil Ottawa, Canada

3 What is this about? 3

4 What is this about? This is not about any particular BSD 3

5 What is this about? This is not about any particular BSD This presentation is about how we think about coding 3

6 What is this about? This is not about any particular BSD This presentation is about how we think about coding The opinions expressed are those of the author and do not reflect the opinions of any BSD project... 3

7 What is this about? This is not about any particular BSD This presentation is about how we think about coding The opinions expressed are those of the author and do not reflect the opinions of any BSD project... - Yes, this is a bit of a rant 3

8 A Challenge 4

9 A Challenge If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1000 MPG. 4

10 A Challenge If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1000 MPG. 4

11 A Challenge If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1000 MPG. Bill Gates 4

12 A Challenge If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1000 MPG. Bill Gates 4

13 A Challenge If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1000 MPG. Bill Gates People who build software are soooo much more innovative than people who build cars. 4

14 A Challenge If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1000 MPG. Bill Gates People who build software are soooo much more innovative than people who build cars. 4

15 A Challenge If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1000 MPG. Bill Gates People who build software are soooo much more innovative than people who build cars. Or are we? 4

16 Just how is GM doing? 5

17 How about Microsoft? 6

18 MSFT vs. GM Who s Better? 7

19 GM s Original Product 8

20 GM s Latest Product 9

21 Sometimes you take a wrong turn 10

22 and you never recover... 11

23 Changing Internals of Autos 12

24 Are we assembly line programmers? Automobiles Assembly Line Modular Design Unified UI Just In Time Delivery Software Waterfall Model Modules Objects Components Re-use Design Patterns 13

25 Parts Used in Construction Automobile Engine Brakes Drive Train Wheels Transmission Door Locks Exhaust System Operating System Kernel Scheduler Memory VM I/O Filesystem Sockets 14

26 MSFT s Early Product 15

27 MSFT s Latest Product 16

28 Early Innovation? 17

29 Still thinking differently? 18

30 One of our early products 19

31 One of our recent products 20

32 Never forget your history! 21

33 Well, perhaps that s just UIs 22

34 Well, perhaps that s just UIs Users force us to provide these types of systems. 22

35 Well, perhaps that s just UIs Users force us to provide these types of systems. Paradigm shift is hard. 22

36 Well, perhaps that s just UIs Users force us to provide these types of systems. Paradigm shift is hard. If we make it too different it won t sell. 22

37 Well, perhaps that s just UIs Users force us to provide these types of systems. Paradigm shift is hard. If we make it too different it won t sell. We re just implementing the marketing spec! 22

38 Well, perhaps that s just UIs Users force us to provide these types of systems. Paradigm shift is hard. If we make it too different it won t sell. We re just implementing the marketing spec! What s under the hood is totally different! 22

39 Changing Internals of OSs 23

40 How Different Are We? BSD Linux Windows Mac OS C C C C/C++ Kernel Kernel Kernel ukernel? VM VM VM VM Processes Processes Processes Processes Threads Threads Threads Threads Events UI Events UI Events UI Events UI 24

41 Why do we fail to provide new models? 25

42 Why do we fail to provide new models? What we were taught? 25

43 Why do we fail to provide new models? What we were taught? What the people want? 25

44 Why do we fail to provide new models? What we were taught? What the people want? What we want? 25

45 Why do we fail to provide new models? What we were taught? What the people want? What we want? These are the best models? 25

46 Why do we fail to provide new models? What we were taught? What the people want? What we want? These are the best models? Our languages and environment dictate our models? 25

47 How do most programmers program? 26

48 How do most programmers program? Text structured in various (non)sensical ways 26

49 How do most programmers program? Text structured in various (non)sensical ways Edit, Compile, Link, Run, Debug cycle 26

50 How do most programmers program? Text structured in various (non)sensical ways Edit, Compile, Link, Run, Debug cycle Edit, run, edit, run, edit, run 26

51 How do most programmers program? Text structured in various (non)sensical ways Edit, Compile, Link, Run, Debug cycle Edit, run, edit, run, edit, run Three basic types of languages 26

52 But what are your options? 27

53 But what are your options? Algol 27

54 But what are your options? Algol - Procedural 27

55 But what are your options? Algol - Procedural Lisp 27

56 But what are your options? Algol - Procedural Lisp - Functional 27

57 But what are your options? Algol - Procedural Lisp - Functional Prolog 27

58 But what are your options? Algol - Procedural Lisp - Functional Prolog - Insanity 27

59 How we think in code matters! 28

60 How we think in code matters! Sloppy languages lead to sloppy code 28

61 How we think in code matters! Sloppy languages lead to sloppy code - Almost always 28

62 How we think in code matters! Sloppy languages lead to sloppy code - Almost always Unsafe languages lead to unsafe code 28

63 How we think in code matters! Sloppy languages lead to sloppy code - Almost always Unsafe languages lead to unsafe code - Almost always 28

64 How we think in code matters! Sloppy languages lead to sloppy code - Almost always Unsafe languages lead to unsafe code - Almost always Confusing languages lead to confusing code 28

65 How we think in code matters! Sloppy languages lead to sloppy code - Almost always Unsafe languages lead to unsafe code - Almost always Confusing languages lead to confusing code - Almost always 28

66 How we think in code matters! Sloppy languages lead to sloppy code - Almost always Unsafe languages lead to unsafe code - Almost always Confusing languages lead to confusing code - Almost always Lowering the barrier to entry has lowered the quality of code 28

67 How many words is a comic worth? 29

68 Programmers learn what they live 30

69 Programmers learn what they live If a programmer reads good code she will write good code 30

70 Programmers learn what they live If a programmer reads good code she will write good code If a programmer sees good abstractions he will write good abstractions 30

71 Programmers learn what they live If a programmer reads good code she will write good code If a programmer sees good abstractions he will write good abstractions If a programmer works with good programmers her code will improve 30

72 Programmers learn what they live If a programmer reads good code she will write good code If a programmer sees good abstractions he will write good abstractions If a programmer works with good programmers her code will improve If a programmer works with poor programmers his code will suffer 30

73 Programmers learn what they live If a programmer reads good code she will write good code If a programmer sees good abstractions he will write good abstractions If a programmer works with good programmers her code will improve If a programmer works with poor programmers his code will suffer Don t read crap code! 30

74 Programmers learn what they live If a programmer reads good code she will write good code If a programmer sees good abstractions he will write good abstractions If a programmer works with good programmers her code will improve If a programmer works with poor programmers his code will suffer Don t read crap code! Don t hang out with crap programmers! 30

75 Everything has been discovered! 31

76 Everything has been discovered! Everything that can be invented has been invented. Charles Duell (?) 31

77 Everything has been discovered! Everything that can be invented has been invented. Charles Duell (?) Turns out not to be true 31

78 Will the real Charles Duell... 32

79 Will the real Charles Duell... "Our future progress and prosperity depend upon our ability to equal, if not surpass, other nations in the enlargement and advance of science, industry and commerce. To invention we must turn as one of the most powerful aids to the accomplishment of such a result." Charles Duell 32

80 Stop Re-inventing the Wheel 33

81 Stop Re-inventing the Wheel There does not need to be another list implementation 33

82 Stop Re-inventing the Wheel There does not need to be another list implementation No one needs another hash table 33

83 Stop Re-inventing the Wheel There does not need to be another list implementation No one needs another hash table Tree 33

84 Stop Re-inventing the Wheel There does not need to be another list implementation No one needs another hash table Tree - Dictionary 33

85 Stop Re-inventing the Wheel There does not need to be another list implementation No one needs another hash table Tree - Dictionary Locking API 33

86 Stop Re-inventing the Wheel There does not need to be another list implementation No one needs another hash table Tree - Dictionary Locking API > Spin Lock 33

87 Stop Re-inventing the Wheel There does not need to be another list implementation No one needs another hash table Tree - Dictionary Locking API > Spin Lock Stop fighting over the scraps 33

88 Stop Re-inventing the Wheel There does not need to be another list implementation No one needs another hash table Tree - Dictionary Locking API > Spin Lock Stop fighting over the scraps Stop re-implementing your school projects 33

89 Invent Some New Wheels 34

90 Invent Some New Wheels UNIX should not be the end of the family tree 34

91 Invent Some New Wheels UNIX should not be the end of the family tree - No matter how much we love BSD 34

92 Invent Some New Wheels UNIX should not be the end of the family tree - No matter how much we love BSD Can you imagine if Vista is what our grandchildren will use? 34

93 Invent Some New Wheels UNIX should not be the end of the family tree - No matter how much we love BSD Can you imagine if Vista is what our grandchildren will use? MacOS X? (XI?) 34

94 Invent Some New Wheels UNIX should not be the end of the family tree - No matter how much we love BSD Can you imagine if Vista is what our grandchildren will use? MacOS X? (XI?) Linux? 34

95 How to Find New Wheels 35

96 How to Find New Wheels Read some papers 35

97 How to Find New Wheels Read some papers - Read the abstracts first 35

98 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless 35

99 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch 35

100 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like 35

101 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme 35

102 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme - Perl 35

103 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme - Perl - Python 35

104 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme - Perl - Python - Haskell 35

105 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme - Perl - Python - Haskell - C++ 35

106 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme - Perl - Python - Haskell - C

107 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme - Perl - Python - Haskell - C Don t specialize too much 35

108 How to Find New Wheels Read some papers - Read the abstracts first - Ignore most of them, most are pointless Look at code you wouldn t normally touch Learn a computer language you don t like - Scheme - Perl - Python - Haskell - C Don t specialize too much Lose your religion! 35

109 You must be willing to 36

110 You must be willing to break things 36

111 You must be willing to break things look stupid 36

112 You must be willing to break things look stupid be wrong 36

113 You must be willing to break things look stupid be wrong learn from others 36

114 All Programmers Have 2 Enemies 37

115 All Programmers Have 2 Enemies Hubris 37

116 All Programmers Have 2 Enemies Hubris Not starting projects 37

117 All Programmers Have 2 Enemies Hubris Not starting projects Never finishing a project 37

118 All Programmers Have 2 Enemies Hubris Not starting projects Never finishing a project - OK, all programmers have 3 enemies 37

119 All Programmers Have 2 Enemies Hubris Not starting projects Never finishing a project - OK, all programmers have 3 enemies Off by one errors are a programmer s 3rd enemy 37

120 All Programmers Have 2 Enemies Hubris Not starting projects Never finishing a project - OK, all programmers have 3 enemies Off by one errors are a programmer s 3rd enemy > Counting from 0 37

121 Your time is limited 38

122 Your time is limited You are only going to live to 72 38

123 Your time is limited You are only going to live to 72 - On average 38

124 Your time is limited You are only going to live to 72 - On average You have to work to eat 38

125 Your time is limited You are only going to live to 72 - On average You have to work to eat Most people only ever have 3 original ideas in their life 38

126 Your time is limited You are only going to live to 72 - On average You have to work to eat Most people only ever have 3 original ideas in their life - Not 3 good ideas, just 3 original ideas 38

127 Your time is limited You are only going to live to 72 - On average You have to work to eat Most people only ever have 3 original ideas in their life - Not 3 good ideas, just 3 original ideas You can easily waste your time on the wrong ideas 38

128 Your time is limited You are only going to live to 72 - On average You have to work to eat Most people only ever have 3 original ideas in their life - Not 3 good ideas, just 3 original ideas You can easily waste your time on the wrong ideas Find people who will honestly tell you if your ideas are crap 38

129 Places to start 39

130 Places to start Safe and powerful programming languages 39

131 Places to start Safe and powerful programming languages Anything that measurably reduces complexity 39

132 Places to start Safe and powerful programming languages Anything that measurably reduces complexity Visualization Tools 39

133 Places to start Safe and powerful programming languages Anything that measurably reduces complexity Visualization Tools Real Software Re-use 39

134 Places to start Safe and powerful programming languages Anything that measurably reduces complexity Visualization Tools Real Software Re-use Novel ways of organizing data 39

135 Places to start Safe and powerful programming languages Anything that measurably reduces complexity Visualization Tools Real Software Re-use Novel ways of organizing data Solve the dependency problem 39

136 Thank you for your time 40

137 Get back to work! 41

Chapter 2: Operating-System Structures. Operating System Concepts 9 th Edit9on

Chapter 2: Operating-System Structures Operating System Concepts 9 th Edit9on Silberschatz, Galvin and Gagne 2013 Chapter 2: Operating-System Structures 1. Operating System Services 2. User Operating System