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1 Common Ground And Coordination in Joint Activity A Walkthrough By John Allspaw (CTO, Etsy) 5/25/16 Papers We Love NYC f(x)=x

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The Paper 2 What Should I Read Next? 3 Context 1 Agenda

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3 SECTION # I See Connections!

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4 Priming The Pump of Connections

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4 Priming The Pump of Connections “When the cost of coordinating change increases, one of two things happen. Either people find ways to reduce the coordination/ communication costs, or they stop making changes. The latter is exactly how we end up with large, hard-to-maintain codebases.” Newman, Sam (2015-02-02). Building Microservices (Kindle Locations 3923-3925). O'Reilly Media. Kindle Edition.

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5 Priming The Pump of Connections

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5 “In large organizations where the delivery process is divided between different groups such as development, DBA, operations, testing, etc., the cost of coordination between these silos can be enormous, sometimes stalling the release process in ticketing hell.” Humble, Jez; Farley, David (2010-07-27). Continuous Delivery: Reliable Software Releases through Build, Test, and Deployment Automation Priming The Pump of Connections

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Connections You May See 6 CAP Theorem microservice/monolith justification validation of Conway’s “Law” reification of Dunbar’s Number distributed systems consensus concepts

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7 CAP Theorem microservice/monolith justification validation of Conway’s “Law” reification of Dunbar’s Number distributed systems consensus concepts RESIST THE URGE TO MAP THESE TO THIS PAPER

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8 CHAPTER 7 GROUNDING IN COMMUNICATION HERBERT H. CLARK AND SUSAN E. BRENNAN GROUNDlNG It takes two people working together to play a duet, shake hands, play chess, waltz, teach, or make love. To succeed, the two of them have to coordinate both the content and process of what they are doing. Alan and Barbara, on the piano, must come to play the same Mozart duet. This is coordination of content. They must also synchronize their entrances and exits, coordinate how loudly to play forte and pianissimo, and otherwise adjust to each other’s tempo and dynamics. This is coordination of process. They cannot even begin to coordinate on content without assuming a vast amount of shared information or common ground-that is, mutual knowledge, mutual beliefs, and mutual assumptions (Clark & Carlson, 1982; Clark & Marshall, 1981; Lewis, 1969; Schelling, 1960). And to coordinate on process, they need to update their common ground moment by moment. All collective actions are built on common ground and its accumulation. We thank many colleagues for discussion of the issues we take up here. The research was supported in part by National Science Foundation Grant BNS 83-20284 and a National Science Foundation Graduate Fellowship. Correspondence concerning this chapter should be addressed to Herbert H. Clark, Department of Psychology, Jordan Hall, Building 420, Stanford University, Stanford, CA 94305-2130, or Susan E. Brennan, Department of Psychology, State University of New York at Stony Brook, Stony Brook NY 11794-2500. 127

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9 Dr. Paul Feltovich B.S., Math PhD, Educational Psychology Post-doc, Cognitive Psychology Dr. Jeff Bradshaw B.S., Math PhD, Cognitive Science Post-doc, Cognitive Psychology Dr. David Woods PhD, Cognitive Psychology Dr. Gary Klein PhD, Experimental Psychology

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Background Studies Relay races Driving in traffic Coaching high school football teams 10

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11 A Note On Models

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Herbert Clark 12

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Noticed that people repair when they miscommunicate. Usually, these miscommunications aren’t “fatal”. Herbert Clark 12

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Noticed that people repair when they miscommunicate. Usually, these miscommunications aren’t “fatal”. People have a repair process that is ongoing. Herbert Clark 12

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Noticed that people repair when they miscommunicate. Usually, these miscommunications aren’t “fatal”. People have a repair process that is ongoing. People are sensitive to each other during the process of communicating. Herbert Clark 12

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“pertinent mutual knowledge, mutual beliefs, and mutual assumptions that support interdependent actions in some joint activity.” Common Ground 13

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14 Not a thing. Not a state. Instead: grounding

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Common ground does not mean knowing the same things! 15

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Common ground does not mean knowing the same things! • A process during communication where I understand the other’s person’s perspective. I can understand the relationship between their knowledge, beliefs, and assumptions and my own. 15

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Common ground does not mean knowing the same things! • A process during communication where I understand the other’s person’s perspective. I can understand the relationship between their knowledge, beliefs, and assumptions and my own. • We invest in the process of grounding to avoid miscommunication. In other words, we’re continually repairing. 15

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Common ground does not mean knowing the same things! • A process during communication where I understand the other’s person’s perspective. I can understand the relationship between their knowledge, beliefs, and assumptions and my own. • We invest in the process of grounding to avoid miscommunication. In other words, we’re continually repairing. • We monitor it by asking explicitly about our knowledge, beliefs, and assumptions. 15

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Common ground does not mean knowing the same things! • A process during communication where I understand the other’s person’s perspective. I can understand the relationship between their knowledge, beliefs, and assumptions and my own. • We invest in the process of grounding to avoid miscommunication. In other words, we’re continually repairing. • We monitor it by asking explicitly about our knowledge, beliefs, and assumptions. • Detecting a mismatch in common ground is one of the primary ingredients in comedy. 15

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Airplane, Paramount Pictures, 1980

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Airplane, Paramount Pictures, 1980

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Dr. Rumack (Leslie Neilsen)

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You’d better tell the Captain Dr. Rumack (Leslie Neilsen)

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You’d better tell the Captain We’ve got to land as soon as we can Dr. Rumack (Leslie Neilsen)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital Dr. Rumack (Leslie Neilsen)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital Dr. Rumack (Leslie Neilsen) Elaine Dickinson (Julie Hagerty)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital Dr. Rumack (Leslie Neilsen) Elaine Dickinson (Julie Hagerty)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? Dr. Rumack (Leslie Neilsen) Elaine Dickinson (Julie Hagerty)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? Dr. Rumack (Leslie Neilsen) Dr. Rumack (Leslie Neilsen) Elaine Dickinson (Julie Hagerty)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? It’s a big building with patients Dr. Rumack (Leslie Neilsen) Dr. Rumack (Leslie Neilsen) Elaine Dickinson (Julie Hagerty)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? It’s a big building with patients But that’s not important right now Dr. Rumack (Leslie Neilsen) Dr. Rumack (Leslie Neilsen) Elaine Dickinson (Julie Hagerty)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? It’s a big building with patients But that’s not important right now Tell the Captain I must speak to him Dr. Rumack (Leslie Neilsen) Dr. Rumack (Leslie Neilsen) Elaine Dickinson (Julie Hagerty)

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? It’s a big building with patients But that’s not important right now Tell the Captain I must speak to him

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? It’s a big building with patients But that’s not important right now Tell the Captain I must speak to him

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? It’s a big building with patients But that’s not important right now Tell the Captain I must speak to him

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You’d better tell the Captain We’ve got to land as soon as we can This woman has to be gotten to a hospital A hospital What is it? It’s a big building with patients But that’s not important right now Tell the Captain I must speak to him

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The Pink Panther Strikes Again, MGM, 1976

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The Pink Panther Strikes Again, MGM, 1976

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Does your dog bite? Insp. Clouseau (Peter Sellers)

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Does your dog bite? Insp. Clouseau (Peter Sellers) QUESTION

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Does your dog bite? Insp. Clouseau (Peter Sellers) No. Inkeeper QUESTION

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Does your dog bite? Insp. Clouseau (Peter Sellers) No. Inkeeper ANSWER QUESTION

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Does your dog bite? Insp. Clouseau (Peter Sellers) No. Inkeeper I thought you said your dog does not bite. Insp. Clouseau (Peter Sellers) ANSWER QUESTION

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Does your dog bite? Insp. Clouseau (Peter Sellers) No. Inkeeper I thought you said your dog does not bite. Insp. Clouseau (Peter Sellers) That is not my dog. Inkeeper ANSWER QUESTION

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Does your dog bite? Insp. Clouseau (Peter Sellers) No. Inkeeper I thought you said your dog does not bite. Insp. Clouseau (Peter Sellers) That is not my dog. Inkeeper ANSWER QUESTION

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Does your dog bite? Insp. Clouseau (Peter Sellers) No. Inkeeper I thought you said your dog does not bite. Insp. Clouseau (Peter Sellers) That is not my dog. Inkeeper ANSWER QUESTION Shared views of the world establish context

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The Bedford Incident, Columbia, 1965

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The Bedford Incident, Columbia, 1965

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Captain, you are a fool Cmdr Wolfgang Schrepke

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Finlander, leave it alone Ben Munceford Captain, you are a fool Cmdr Wolfgang Schrepke

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready Captain Eric Finlander U.S.N. Take it easy

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready Captain Eric Finlander U.S.N. Take it easy Ensign Ralston Fire control A.O.K. sir... all systems armed and ready... ready

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready Captain Eric Finlander U.S.N. Take it easy Ensign Ralston Fire control A.O.K. sir... all systems armed and ready... ready This is insane Cmdr Wolfgang Schrepke

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready Captain Eric Finlander U.S.N. Take it easy Ensign Ralston Fire control A.O.K. sir... all systems armed and ready... ready This is insane Cmdr Wolfgang Schrepke Now don’t worry commodore Captain Eric Finlander U.S.N.

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready Captain Eric Finlander U.S.N. Take it easy Ensign Ralston Fire control A.O.K. sir... all systems armed and ready... ready This is insane Cmdr Wolfgang Schrepke Now don’t worry commodore Captain Eric Finlander U.S.N. the Bedford will never fire first

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready Captain Eric Finlander U.S.N. Take it easy Ensign Ralston Fire control A.O.K. sir... all systems armed and ready... ready This is insane Cmdr Wolfgang Schrepke Now don’t worry commodore Captain Eric Finlander U.S.N. the Bedford will never fire first but if he fires one, I’ll fire one

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Finlander, leave it alone Ben Munceford Captain Eric Finlander U.S.N. Take it easy, Ralston Captain, you are a fool Cmdr Wolfgang Schrepke Ensign Ralston All systems in automatic control sir... weapons armed and ready Captain Eric Finlander U.S.N. Take it easy Ensign Ralston Fire control A.O.K. sir... all systems armed and ready... ready This is insane Cmdr Wolfgang Schrepke Now don’t worry commodore Captain Eric Finlander U.S.N. the Bedford will never fire first but if he fires one, I’ll fire one Fire one Ensign Ralston

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A Convoy As a Distributed Team

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INTENTION INTERDEPENDENCE 24 Criteria for “joint activity”

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25 Basic Compact Criteria for “joint activity” INTENTION

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25 Basic Compact “constitutes a level of commitment for all parties to support the process of coordination.” Criteria for “joint activity” INTENTION

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25 Basic Compact “constitutes a level of commitment for all parties to support the process of coordination.” Goal Alignment Criteria for “joint activity” INTENTION

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26 Criteria for “joint activity” INTERDEPENDENCE

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26 “what party “A” does must depend in some significant way on what party “B” does and vice versa.” Criteria for “joint activity” INTERDEPENDENCE

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26 “what party “A” does must depend in some significant way on what party “B” does and vice versa.” Mutual influence Criteria for “joint activity” INTERDEPENDENCE

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INTERPREDICTABILITY C O M M O N G R O U N D D I R E C TA B I L I T Y 27 Requirements for “joint activity”

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INTERPREDICTABILITY C O M M O N G R O U N D D I R E C TA B I L I T Y 28 Requirements for “joint activity”

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INTERPREDICTABILITY C O M M O N G R O U N D D I R E C TA B I L I T Y 29 Requirements for “joint activity”

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30 1.Initial common ground 2.Public events so far 3.Current state of the activity Requirements for “joint activity” C O M M O N G R O U N D

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31 Joint Activity

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31 Joint Activity depends on

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31 Joint Activity interpredictability depends on

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31 Joint Activity interpredictability depends on based on

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31 Joint Activity interpredictability common ground depends on based on

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31 Joint Activity interpredictability common ground depends on based on defined as

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31 Joint Activity interpredictability common ground depends on based on defined as mutual knowledge mutual beliefs mutual assumptions

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31 Joint Activity interpredictability common ground depends on based on defined as assumes a mutual knowledge mutual beliefs mutual assumptions

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31 Joint Activity interpredictability common ground depends on based on defined as Basic Compact assumes a mutual knowledge mutual beliefs mutual assumptions

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31 Joint Activity interpredictability common ground depends on based on defined as Basic Compact assumes a which is a mutual knowledge mutual beliefs mutual assumptions

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31 Joint Activity interpredictability common ground depends on based on defined as Basic Compact assumes a commitment to participate and align goals which is a mutual knowledge mutual beliefs mutual assumptions

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PHA SE S SI GNAL I NG C O O R D I N AT I O N D E V I C E S C O O R D I N AT I O N C O S T S 32 Choreography of “joint activity”

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33 Choreography of “joint activity” Phases ENTRY B O D Y O F A C T I O N EXI T

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34 Choreography of “joint activity” Signaling

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35 Choreography of “joint activity” Coordination Devices

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35 Choreography of “joint activity” Coordination Devices AGR EEMEN T

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35 Choreography of “joint activity” Coordination Devices AGR EEMEN T CO NV EN TION

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35 Choreography of “joint activity” Coordination Devices AGR EEMEN T CO NV EN TION PRECEDEN T

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35 Choreography of “joint activity” Coordination Devices AGR EEMEN T CO NV EN TION PRECEDEN T SALIENCE

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36 Choreography of “joint activity” Coordination Costs

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36 Choreography of “joint activity” Coordination Costs SYNC HRONI ZATI ON OVERHEAD

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36 Choreography of “joint activity” Coordination Costs SYNC HRONI ZATI ON OVERHEAD CO MMU NI CAT I ON OVERH EAD

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36 Choreography of “joint activity” Coordination Costs SYNC HRONI ZATI ON OVERHEAD CO MMU NI CAT I ON OVERH EAD RE DIRECTION OVERHEAD

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36 Choreography of “joint activity” Coordination Costs SYNC HRONI ZATI ON OVERHEAD CO MMU NI CAT I ON OVERH EAD RE DIRECTION OVERHEAD DIAGN OSI S OVERHEAD

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38 http://bit.ly/AllspawThesis

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Ethnographic Coding

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IE2 PE2 IE5 IE1 IE1 PE3 IE3 PE3 PE3 ProdEng1 re-enables the sidebar, with blog turned off 13:06:44 13:15:00 13:30:00 13:45:00 14:00:00 14:15:00 14:30:00 ProdEng2 turns off homepage sidebar module disable a CDN? Load balancer changes? Network changes? Wordpress issue? Frozen shop? Featured shop? PE1 PE1 Varnish queuing? Featured staff shop? Sidebar loading staff shop? IE1 IE1 IE1 IE1 IE1 IE1 IE1 Varnish not caching? IE3 Database schema change? IE2 IE2 IE1 Errors from Homepage sidebar IE2 400 response code IE2 PublicShops_GetShopCards API method PE3 Featured shop loading OK IE2 “Shop 1234567 does not exist” Varnish queuing, not caching 400 responses? Stated hypothesis Critical relayed observation

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44 BACK TO THE PAPER

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45 some ‘most important’ types

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45 some ‘most important’ types •the roles and functions of each participant;

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45 some ‘most important’ types •the roles and functions of each participant; •the routines that the team is capable of executing;

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45 some ‘most important’ types •the roles and functions of each participant; •the routines that the team is capable of executing; •the skills and competencies of each participant;

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45 some ‘most important’ types •the roles and functions of each participant; •the routines that the team is capable of executing; •the skills and competencies of each participant; •the goals of the participants, including their commitment to the success of the team activity; and

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45 some ‘most important’ types •the roles and functions of each participant; •the routines that the team is capable of executing; •the skills and competencies of each participant; •the goals of the participants, including their commitment to the success of the team activity; and •the “stance” of each participant (e.g., his or her perception of time pressure, level of fatigue, and competing priorities).

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Fundamental Common Ground Breakdown 46

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Fundamental Common Ground Breakdown 46 • Party A believes that Party B possesses some knowledge.

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Fundamental Common Ground Breakdown 46 • Party A believes that Party B possesses some knowledge. • Party B doesn’t have this knowledge, and doesn’t know he or she is supposed to have it.

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Fundamental Common Ground Breakdown 46 • Party A believes that Party B possesses some knowledge. • Party B doesn’t have this knowledge, and doesn’t know he or she is supposed to have it. • Therefore, he or she doesn’t request it.

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Fundamental Common Ground Breakdown 46 • Party A believes that Party B possesses some knowledge. • Party B doesn’t have this knowledge, and doesn’t know he or she is supposed to have it. • Therefore, he or she doesn’t request it. • This lack of a request confirms to Party A that Party B has the knowledge.

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“We are asserting that people need to have a model of the machine as an agent participating in the joint activity.” p.169 47

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50 “I WANT TO TREAT THE PATIENT- NOT THE ALARM” USER IMAGE MISMATCH IN ANESTHESIA ALARM DESIGN Thesis/Project work submitted in partial fulfillment of the requirements for the MSc in Human Factors and System Safety Karen Raymer, M.D., FRCP(C) LUND UNIVERSITY SWEDEN Date of submission: 2012-06-04

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53 Parting Thought

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54

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54 “As alternative to CAP, we propose a "delay-sensitivity" framework, which analyzes the sensitivity of operation latency to network delay, and which may help practitioners reason about the trade-offs between consistency guarantees and tolerance of network faults.”

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55

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55 “Alternative OSs like microkernels have long been considered more stable and easier to reason about by the systems community, but the performance overhead that comes with running them means typically our OSs still resemble the ones from the ‘60s."

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56

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56 “For those who don't think they're interested in compilers, consider how insight into JIT optimizations can help you reason about the performance of all that JavaScript, JVM, and .NET code you interact with all the time!”

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57

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57 What does it mean to reason about something?

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57 What does it mean to reason about something? Does reasoning come only from our minds?

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57 What does it mean to reason about something? Does reasoning come only from our minds? Do we reason when we’re participating in joint activity?

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QUESTIONS? 58 The End