The Digital Machine is a model-based method for designing software. This presentation explains how the systems thinking concepts of elements, relationships, purpose, feedback and state can be used to develop the 5 critical models that make up the Digital Machine: - conceptual model - persona model - interaction model - object model - data model

1. THIS WORK
THE DIGITAL
MACHINE
Transforming Systems to Software
Tim Sheiner
Systems Class Visit 2015

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A system is an interconnected set of
elements that is coherently organized
in a way that achieves something.
2
Donella Meadows, Thinking in Systems

3. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
A System has
3
Elements
Connections
Purpose.
A
B C

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And State.
4
state
A
B C
State describes what is
currently true about the
objects and relationships in
the system.

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Dynamic Systems Change State.
5
state’
time
A
B C
A
B C
state

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This is important:
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dynamics systems change state.

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State Change == Purpose
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state’
time
state

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Software version
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state’
time
state

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HOW?
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MODELS
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make it possible.

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MODELS
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let us talk about complicated things.

12. 12
Dubberly, Models of Models, 2009

13. 12
Dubberly, Models of Models, 2009
Models let me put
my ideas in your head
Models let me put
my ideas in your head

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All models are wrong
13
but some are useful.
George P. Box

15. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
A useful model for
making software
14
The Digital Machine

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designer
developer
Software
User Process
Observational
Model
Algorithmic
Model

17. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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Software
User Process
Algorithmic
Model
Observational
Model
designer
developer

18. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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Software
User Process
Algorithmic
Model
Observational
Model
designer
developer

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Observational
Model
Algorithmic
Model
Digital Machine

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21. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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interaction model
object model
data model
persona model
conceptual model

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interaction model
object model
data model
persona model
conceptual model

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interaction model
object model
data model
persona model
conceptual model
what is the purpose?
who is it for?
how do I use it?
what are the elements?
how is state managed?

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conceptual
model
output
input
interaction
model
storage
logic
object model
data modelpersona
model
{ }name:value
name:value
name:value
the digital machine

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Value of the Digital Machine
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conceptual
model
output
input
interaction
model
storage
logic
object model
data modelpersona
model
{ }
name:value
name:value
name:value
1. It is a collaboration
2. The models can be iterated
separately, for a time,
without losing sight of the
whole
3. There is a model for every
stakeholder’s point of view

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THE MODELS
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The Conceptual Model
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for understanding the purpose.

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conceptual
model
output
input
interaction
model
storage
logic
object model
data modelpersona
model
{ }name:value
name:value
name:value

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Conceptual Model
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is a about purpose
For target customers
Who have a particular need
This product is a category of solution
That provides a key benefit
Unlike the competition

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Conceptual Model
1. Defines purpose: what problem gets solved for whom
2. Identifies value & utility
3. Does not describe use cases, interface or implementation
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The Persona Model
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describes behavior.

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conceptual
model
output
input
interaction
model
storage
logic
object model
data modelpersona
model
{ }name:value
name:value
name:value

33. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
Persona Model
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Persona Model
1. Is a model of human behavior, goals and emotions
2. The most established design practice model with lots of
literature and examples
3. Derives communication power from natural human instinct
for empathy
4. The more real the representation the more effective the
consensus
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The Interaction Model
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for how to change state.

36. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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conceptual
model
output
input
interaction
model
storage
logic
object model
data modelpersona
model
{ }name:value
name:value
name:value

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By a state of a system is meant any well-
defined condition or property that can be
recognized if it occurs again. Every system
will naturally have many possible states.
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Ashby, An Introduction to Cybernetics, 1956

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How Do I Change State?
The interaction model defines how to manipulate system
state
1. how do I interact with the system?
2. what are the workflows?
3. how do inputs become outputs?
4. how do I get feedback that the state has changed?
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What is Interaction?
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action
feedback
System
input
output

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Interaction Changes State
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action
input
output
feedback
A
B C
A
B C
state’
state

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Object Change is System Change
37
state’
time
A
B C
A
B C
state

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System Change is a Flow
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A B

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Each Step is a State Change
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B C
D E
A

44. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
Each Step is a State Change
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A B C
D E

45. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
Each Step is a State Change
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46. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
The Interaction Model is a Process Story
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47. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
The Interaction Model is a Process Story
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48. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
The Interaction Model is a Process Story
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49. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
The Interaction Model is a Process Story
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50. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
The Interaction Model is a Process Story
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Interaction Model
1. The easiest model for people to connect with (and the one
everyone has an opinion about)
2. Maps inputs to outputs
3. Organized into workflows
4. Defines process by which a system changes state
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The Object Model
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describes the positions and the players.

53. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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conceptual
model
output
input
interaction
model
storage
logic
object model
data modelpersona
model
{ }name:value
name:value
name:value

54. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
Design a game
46
about riding a bicycle.

55. 47

56. 47

57. 48

58. 48
handle bar
handle
grip
handgrip
control
?grip

59. 48
grip

60. 49
grip

61. 49
rotation
grip

62. 49
X
rotation
grip

63. 49
rotation
grip
inclination

64. 49
rotation
grip
inclination
gravity

65. 50
gravity
rotation
inclination
grip

66. 50
gravity
rotation
inclination
grip

67. 50
gravity
rotation
inclination
grip
transportation!

68. 50
gravity
destination
rotation
inclination
grip
transportation!

69. 50
gravity
destinationorigin
rotation
inclination
grip
transportation!

70. 50
gravity
destinationorigin
position
rotation
inclination
grip
transportation!

71. 50
gravity
destinationorigin
position
trip
rotation
inclination
grip
transportation!

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trip
Object Model
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vehicle
origin
destination
bicyclerider
grip

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Object Model
1. The elements and relationships of the system that work
together to achieve purpose.
2. The most personal and the most confusing.
3. Describes concepts, their capabilities and their relationships.
4. Names matter. A lot.
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trip
Object Model
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vehicle
origin
destination
bicyclerider
position
rotation
inclination
grip
What about the properties?
How is state retained?
(system)dt
d
state change =

75. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
The Data Model
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identifies the object properties.

76. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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conceptual
model
output
input
interaction
model
storage
logic
object model
data modelpersona
model
{ }name:value
name:value
name:value

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WHAT IS DATA?
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(in the software context)

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name : value
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lat : '37.78'
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position
:
{
lat
:
'37.78',
long
:
'-­‐122.42'
}

81. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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a set of name : value
pairs defines object
state
position
:
{
lat
:
'37.78',
long
:
'-­‐122.42'
}

82. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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trip
vehicle
origin
destination
bicyclerider
grip

83. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
bikeTrip
=
{
vehicle
:
{
rider
:
{
name
:
'Kyle'
},
bicycle
:
{
grip
:
{
rotation
:
'12',
inclination
:
'3'
}
},
position
:
{
lat
:
'37.78',
long
:
'-­‐122.42'
},
},
origin
:
{
name
:
'San
Francisco',
position
:
{
lat
:
'37.78',
long
:
'-­‐122.42'
},
destination
:
{
name
:
'Los
Angeles',
position
:
{
lat
:
'34.05',
long
:
'-­‐118.24'
}
}
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a set of object
states defines
system state
trip
vehicle
origin
destination
bicyclerider
grip

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Value Change == State Change == Purpose
61
state’
time
state
position
:
{
lat
:
'37.78',
long
:
'-­‐122.42'
}
position
:
{
lat
:
'34.05',
long
:
'-­‐118.24'
}

85. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
bikeTrip
=
{
position
:
{
lat
:
'
',
long
:
'
'
}
}
37.78 -­‐122.42
62
(system)dt
d
state change =

86. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
bikeTrip
=
{
position
:
{
lat
:
'
',
long
:
'
'
}
}
37.78 -­‐122.42
62
(system)dt
d
state change =

87. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
bikeTrip
=
{
position
:
{
lat
:
'
',
long
:
'
'
}
}
37.78 -­‐122.42
62
interaction model
(system)dt
d
state change =

88. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
bikeTrip
=
{
position
:
{
lat
:
'
',
long
:
'
'
}
}
62
34.05 -­‐118.24
interaction model
(system)dt
d
state change =

89. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
Data Model Defines State
63
The names do not change.
The values change to reflect system state.

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Data Model
1. The atomic structure is name:value pairs
2. A set of name:value pairs defines object state
3. A set of object states defines system state
4. The data model, therefore, defines what can read or written
5. Or more simply, what can be changed
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65
conceptual
model
output
input
interaction
model
storage
logic
object model
data model
persona
model
{ }name:value
name:value
name:value
the digital machine

92. THIS WORK BY TIM SHEINER LICENSED UNDER A CREATIVE COMMONS ATTRIBUTION 3.0 UNITED STATES
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conceptual
model
output
input
interaction
model
storage
logic
object model
data model
persona
model
{ }name:value
name:value
name:value
Software
User Process
Observational
Model
Algorithmic Model
the digital machine

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FIN
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