The document discusses how software architecture and tool architecture impact a continual flow of value in software development. It argues that software architecture needs to evolve gracefully over time to enable value delivery, and that tools should support human and tool interactions to facilitate appropriate architectural decisions. However, tool architecture is often ignored despite likely interactions with software architecture. More research is needed to understand these relationships and how tool architecture can support software architecture evolution.

1. The (Un)Expected Impact
of Tools
in Software Evolution
Gail C. Murphy
University of British Columbia
@gail_murphy
except for images where noted

2. “The way humans
make and use tools
is perhaps what
sets our species
apart more than
anything else.”
Charles Q. Choi
ROOBE Art Company
+
https://www.livescience.com/7968-human-evolution-origin-tool.html 2

3. +
Building a
“simple” physical
artifact
multiple
specialized tools
interactions:
human with tools
humans with artifacts
3
Images above not copyable

4. + Building a
“complex” physical
artifact
multiple
specialized workers
& tools
interactions:
humans with tools
humans with humans
artifacts with artifacts

5. +
5
Building many
“complex” physical artifacts
enable a flow of
produced physical artifacts
interactions:
humans with tools
tools with tools
artifacts with artifacts
Images above not copyable

6. Which is most
similar to
producing a
software product?
+
6
C

7. +
7
humans with tools
humans with humans
artifacts with artifacts
humans with tools
tools with tools
artifacts with artifacts
Combination of both
Images above not copyable

8. +
8
(Most) Software product development aims to
provide a continual flow of value to customers
V1.1 V2.9
…
Software Architecture
Analyst Dev IT Ops QA
V1
V3
.
.
.
Tool Architecture
Interaction between these architectures needs study

9. +
8
(Most) Software product development aims to
provide a continual flow of value to customers
V1.1 V2.9
…
Analyst Dev IT Ops QA
V1
V3
.
.
.
Software Architecture Tool Architecture
Interaction between these architectures needs study
My goal with this talk
is to raise more questions than I answer

10. I. Value
II. Software
Architecture
III. Tool
Architecture
IV. Open
Questions

11. +
I. Value

12. +
11
(Most) Software product development aims to
provide a continual flow of value to customers
“the importance, worth, or
usefulness of something”
Value is…
Value in software…
delivered requirements
Images above not copyable

13. +
12
(Most) Software
product development
aims to provide a
continual flow of value
to customers

14. 13
Software
architecture plays
a key role
in enabling a
flow of value delivery
“On the criteria to be used
decomposing systems into
modules “
- Parnas 1972
“Foundations for the study of
software architecture”
- Perry and Wolf 1992

15. Different modularizations (“architectures”)
carry different option values
Software architecture can ease continual
delivery of value to customers

16. +
15
…
…
Analysts
Developers
…
QA
Tooling plays a role in enabling value delivery

17. +
15
…
…
Analysts
Developers
…
QA
Tooling plays a role in enabling value delivery

18. +
15
…
…
Analysts
Developers
…
QA
Tooling plays a role in enabling value delivery
Tool to tool
interaction
can facilitate
human to human
interaction

19. +
16
Zohaiib Khan
Principle Domain Architect
Red Hat Inc
https://techbeacon.com/app-dev-testing/role-devops-new-methods-finally-deliver-business-value
https://commons.wikimedia.org/wiki/File:Devops-toolchain.svg

20. Delivery of value impacted by architecture and tools
17
I. Value

21. +
II. Software
Architecture

22. +
Many perspectives on software architecture
19
Logical
View
Process
View
Development
View
Physical
View
4+1 View Model [Krutchen 1995]

23. Software architecture continually evolves …
+
20

24. Software architecture continually evolves …
and often degrades impacting…
+
20
Quality[DB12] Bugs[PW92] Change[BC10]

25. +
Architectural
drift happens
one decision
at a time
Number of design decisions …
have now proven to be sub-optimal
LogicalPlan and Optimizer are too
complex and hard to work with
Example from [LK+21]

26. Tools focused
on artifacts can
help with drift
Code
Development
PDE API Tools Compiler

27. Tools focused
on human
communication
can help with drift
23

28. Architectural evolution required for continual delivery of value
24
II. Software Architecture
Tools can enable architectural evolution

29. +
III. Tool
Architecture

30. +
Developing most software requires many tools
26

31. +
Projects must organize the tools they use
27
With thanks to Tasktop Technologies Inc. for the diagram.
Diagram is not copyable.

32. What is a tool architecture?
Nodes are specific tools
Sub-nodes are data in tools
Connectors represent data flows
With thanks to Tasktop Technologies Inc. for the diagram.
Diagram is not copyable.

33. What is a tool architecture?
Nodes are important
- what information is being tracked,
managed, etc.
- e.g., is there an architectural
conformance checker?
Connections are important
- what information is accessible
to human users of the tool or other tools?
- e.g., does the checker send information
to the pull request tooling?
With thanks to Tasktop Technologies Inc. for the diagram.
Diagram is not copyable.

34. Code
Development
PDE API Tools Compiler
humans with tools
artifacts with artifacts
30
humans with humans tools with tools
Impacted by tool architecture Images above not copyable

35. +
Project tool architectures differ
31
Tool architecture can
impact evolution of software
architecture because information
access can enable different
decision making
With thanks to Tasktop Technologies Inc. for the diagram
Diagram is not copyable.
.

36. Researchers tool
architectures
Images above not copyable

37. Tool architecture can ease evolution of software architecture
33
III. Tool Architecture
But what aspects of tool architecture are important?
With thanks to
Tasktop
Technologies
Inc. for the
diagram.
Diagram is not
copyable.

38. +
IV. Open
Questions

39. What should be captured in a
description of a project’s tool
architecture?
How do we model information flow
through the tool architecture
effectively?
35
Analyst Dev IT Ops QA
V1
V3
.
.
.
Tool Architecture

40. V1.1 V2.9
…
Software Architecture
Should we describe the tool
architecture when studying
software architecture evolution?
Can we affect the evolution of a
software architecture by modifying
the tool architecture?
36

41. V1.1 V2.9
…
Software Architecture
37
Analyst Dev IT Ops QA
V1
V3
.
.
.
Tool Architecture
When should changes in the software architecture
indicate a change is needed in the project’s tool
architecture?

42. 38
Analyst Dev IT Ops QA
V1
V3
.
.
.
Tool Architecture
How does Conway’s law impact a project’s
tool architecture?
“Any organization that designs a
system (defined broadly) will
produce a design whose structure is
a copy of the organization's
communication structure.”
— Melvin E. Conway

43. 38
Analyst Dev IT Ops QA
V1
V3
.
.
.
Tool Architecture
V1.1 V2.9
…
Software Architecture
How does Conway’s law impact a project’s
tool architecture?
And does that interplay with the software architecture?
Or is it vice versa?

44. +
Summary

45. +
@xped0829 via Twenty20
Thank you to the organizes of ICSA/SANER
for the invitation to speak.
Thank you to Mik Kersten and my colleagues
at Tasktop Technologies for an amazing
15 year journey.
Thank you to my students for their insights,
discoveries and making research fun.
Images above not copyable

46. +
(Most) Software product development aims to
provide a continual flow of value to customers
41

47. +
(Most) Software product development aims to
provide a continual flow of value to customers
V1.1 V2.9
…
Software Architecture
A continual flow of value is enabled
by a software architecture that
evolves gracefully
42

48. +
(Most) Software product development aims to
provide a continual flow of value to customers
V1.1 V2.9
…
Software Architecture
A continual flow of value is enabled
by a software architecture that
evolves gracefully
42
and by tools that support
human - tool interactions
human - human interactions
to make appropriate decisions

49. +
(Most) Software product development aims to
provide a continual flow of value to customers
V1.1 V2.9
…
Software Architecture
But we tend to ignore the tools and
how they are architected to support
software development
43

50. +
(Most) Software product development aims to
provide a continual flow of value to customers
V1.1 V2.9
…
Software Architecture
Analyst Dev IT Ops QA
V1
V3
.
.
.
Tool Architecture
45

51. +
(Most) Software product development aims to
provide a continual flow of value to customers
V1.1 V2.9
…
Software Architecture
Analyst Dev IT Ops QA
V1
V3
.
.
.
Tool Architecture
Interaction between these architectures needs study
@gail_murphy

52. [BC10] H. P. Breivold and I. Crnkovic, “A systematic review on architecting for software evolvability”. Proc. of the 21st Australian
Software Engineering Conference (ASWEC), pp. 13–22, IEEE, 2010.
[BM+14] J. Brunet, G.C. Murphy, D. Serrey and J. Figueiredo. Five years of software architecture checking: A case study of Eclipse.
IEEE Software, vol. 32, no. 5, pp. 30-36. 2014.
[DB12] L. De Silva and D. Balasubramaniam, “Controlling software architecture erosion: A survey.” Journal of Systems and Software,
vol. 85, no. 1, pp. 132–151, 2012.
[LK+21] D. Minh Le, S. Karthik, M. Schmitt Laser and N. Medvidovic. “Architectural decay as predictor of issue- and change- proneness.
Proc. of International Conference on Software Architecture, 2021.
[P72] D. Parnas. On the criteria to be used in decomposing systems into modules. CACM, vol. 15, no. 12, pp. 1053-1058, 1972.
[PW92] D. E. Perry and A. L. Wolf, “Foundations for the study of software architecture.” ACM SIGSOFT Software Engineering Notes,
vol. 17, no. 4, pp. 40–52, 1992.
[S+01] K. Sullivan, W.G. Griswold, Y. Cai and B. Hallen. The structure and value of modularity in software design, ACM SIGSOFT
SEN, vol. 26, no. 5, pp. 99-108, 2001.
References