SeeSys: SpaceFilling Software Visualization Marla J. Baker Stephen G. Eick AT

1
SeeSys Space-Filling Software VisualizationMarla
J. BakerStephen G. EickATT Bell Labs
2
Description of the paper

• A concrete application of TreeMaps
• Influenced by Dynamic Queries as well
• Provides a high-level visualization of a
  large-scale software engineering project
• A fast way of getting an overview from a CVS
  repository?
• In other words CVS for management
• This is a real-world application!

3
What questions do we want to answer visually?

• Which subsystems are the largest? Where is new
  development activity?
• Where are the large directories? How are the
  directories changing?
• What proportion of work on a subsystem relates to
  fixing bugs as opposed to adding new
  functionality?
• What components are candidates for code
  restructuring, based on their histories of
  required bug fixes?
• How are the subsystems changing between releases?

4
What assumptions must we make about the
information to be visualized?

• The Data must be
• Quantitative Why? So we can easily compare
  different elements and display them with graphs.
• Additive. Why? So we can break a whole up into
  parts, and know that the sum of these parts will
  reproduce the whole.
• TreeMaps seem to require these two notions.

5
Any hidden assumptions?
Yes! Were also assuming that these types of
metrics are easily kept by every programmer on
the project, and feasibly attainable to
SeeSys. Basically, we assume that something like
CVS is running underneath SeeSys. Is this a
valid assumption? Of course! But I wanted to
make this explicit.
6
What can we measure about our target system?

• Non-comment source lines (NCSL)
• Software complexity metrics
• How do we get these?
• Number and scope of modifications
• Number of programmers making modifications
• Number and type of bugs (a subcategory of
  modifications)

7
1) Subsystem Information

• Question Which subsystems are largest?
• Check the area of a bounding box
• Check the color (redundant coloring)
• Question Where is new development taking place?
• Check the gray-fill area of a bounding box
• It is perpendicular to the division of the
  bounding boxes

8
Subsystem Information contd
9
2) Directory Information

• Question Where are the large directories?
• Find the thickest slices of a subsystems
  bounding box
• They are parallel to the division of the
  subsystems
• Larger slices are brighter in hue
• Newly added code is grey filled

10
Directory Information contd
11
Directory Information contdZoom In
12
3) Error-Prone Code

• Question Which subsystems and directories have
  the most bugs?
• No more redundant coloring (why?)
• Area of each subsystem represents new NCLS
• Area of grey-fill is NCSL dedicated to bug fixes
• Blue spikes represent directory bug fixing NCSL
  detail

13
Error-Prone Code contd
14
4) Recurring Problems

• Question What subsystems would make good
  candidates for code restructuring?
• Area of each subsystem represents number of bugs
• Grey-fill area represents fix-on-fix bugs
• Blue spikes again represent directory detail
• Why cant I zoom in here! Ahh!

15
Recurring Problems contd
16
5) System Evolution

• Question How have subsystems changed between
  versions?
• Area of rectangle represents largest size ever
• Colored fill area represents size under current
  version
• Can animate from one version to subsequent
  versions to get a picture over time
• Could this be improved?

17
System Evolution contd
18
System Evolution contd
19
System Evolution contd
20
Favorite Sentence
When applied to production-sized systems,
routines for producing flow-charts, function
call-graphs, and structure diagrams often break
because the display is too complicated. Or they
produce displays that contain too much
information and are illegible. I translate this
to read Unlike the other tools Ive cited, which
are all nice little toys if youre locked away in
your ivory tower, this is not a toy application!
This is a real-world application!
21
Contributions

• Concrete, useful, large-scale, real-world
  application of TreeMaps
• Proof of concept that TreeMaps can handle
  extremely large datasets in a sensible way.
• Showcases effective use of redundant coloring
• Highlights hierarchical zooming from subsystem,
  to directory, to file between versions

22
Contributions contd
Still, much better than this Index
BundleDownloader.java
RCS file
/fs/savoir/pugh/p/cvs/java/daveho/cl/BundleDownloa
der.java,v retrieving revision 1.11 diff -u
-r1.11 BundleDownloader.java ---
BundleDownloader.java 2000/08/29 153149
1.11 BundleDownloader.java 2001/02/07
201553 _at__at_ -56,10 56,11 _at__at_ if ( tag
BundleProtocol.NOTFOUND )
String name m_input.readUTF()
callback.notFound( name )
continue if ( tag !
BundleProtocol.BUNDLE ) - throw new
IllegalArgumentException("Invalid tag byte")
throw new IllegalArgumentException("In
valid tag byte " tag) int
length m_input.readInt() if (
debug )
23
Notes on the references

• Cites the TreeMaps paper (Johnson and
  Schneiderman, 1991)
• Cites work on visualizing line-oriented data,
  such as an idividual source file. This looks
  cool! But its not relevant.
• Cites lots of other papers, too But I think the
  TreeMaps paper is the major influence on this
  work.

24
Critique - weaknesses

• I really want zoomed-in pictures of directories
  with error-prone code and recurring problems!
• Im not sure the techniques used to display
  error-prone code and recurring problems were all
  that great anyway
• The screenshots, even in the original paper, are
  terrible.
• No measurements! I want to see 4 out of 5
  middle managers prefer SeeSys to the leading
  brand.

25
Critique strengths

• Short, simple, elegant paper
• Attacks a real problem
• Doesnt try to do too much SeeSys provides
  high-level visualizations of large, complex
  software systems. Nothing more.

26
What has happened to this topic?My web search
uncovered that

• Google search reveals SeeSys is someones domain
  name, and its an obscure command in MatLab.
• This paper has been referenced 4 times, though 3
  were by the same paper which showed up in a
  couple of places.
• I found that a couple software engineering
  classes study this tool.
• I was not able to uncover any commercial
  organizations that use this particular tool,
  though Im not sure if that information is public
  anyway.

27
Conclusions

• Realistically, what else was left to do?
• SeeSys provides useful, general, effective
  high-level visualizations of any quantitative,
  additive measurements.
• Further useful visualizations would likely be too
  specific to a given system for this generalized
  framework
• Or would need to be done per line of source code.
  This is a very different type of visualization
  problem for which TreeMaps are probably not the
  best medium.
• More sophisticated QA measurements are more
  difficult to obtain at some point, software
  engineering becomes an art

28
My main question Has this been written in Java?
Does GNU have a free version? Can I build this
type of TreeMap interface on top of a CVS
distribution, like jCVS?