The Architecture of Unusual Things

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The Architecture of Unusual Things

• Grady Booch
• IBM Fellow
• gbooch_at_us.ibm.com

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The Limits of Software

• The laws of physics
• The laws of software
• The challenge of algorithms
• The difficulty of distribution
• The problems of design
• The importance of organization
• The impact of economics
• The influence of politics
• The limits of human imagination

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Software Development as a Human Activity
Some designers are equally inept at following
rules or breaking them. Good designers can do
either. Jim Alley Savannah College of Art and
Design

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Some Unusual Things
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Lessons Learned
Everything has an architecture
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The Architecture of Eric

• The human body is composed of ten interdependent
  systems
• Skeletal Muscular Circulatory Nervous
• Respiratory Digestive Excretory Endocrine
• Reproductive Immune
• Each such system is composed of a network of
  interacting tissues and organs
• Every class of tissue and organ is composed of a
  unique collection of cell types
• Over 200 types of cells exist, varying greatly in
  appearance, lifespan, and function
• Every cell is composed of organelles

Dennis and Gallagher, 2003, The Human Genome,
Nature Publishing Group
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The Architecture of Eric

• Multi-cellular organisms rely upon intercellular
  signaling molecules to coordinate the functions
  of different cells

http//receptome.stanford.edu/hpmr/
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The Architecture of Eric

• Every cell type, tissue, organ, and subsystem is
  ultimately regulated by one common mechanism,
  manifest in DNA

http//www.genome.gov
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Lessons Learned
The soul of an architecture is found in its
mechanisms which cut across the components of the
system, thus yielding its essential behaviors
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The Architecture of DNA
Dennis and Gallagher, 2003, The Human Genome,
Nature Publishing Group
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The Architecture of DNA

• To sequence DNA
• Isolate the DNA under investigation
• Use DNA polymerase to make a large number of
  copies
• Cut those copies at random into reasonably sized,
  overlapping pieces, marking the ends of each
  piece with a terminator base
• Order those pieces by size using electrophoresis
• Read the sequence from the progression of
  terminator bases
• To assemble a sequence
• Place all sequences into a DNA library
• Sequence those sequences by matching their
  overlapping parts

3,200,000,000 bases 1,000 raw sequences per
second 9x coverage required for final sequence
http//www.ncbi.nlm.nih.gov/genbank
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The Architecture of a Sequencer

• Two fundamental approaches
• NIH map-based (reliable but slow)
• Celera whole genome shotgun (fast but
  computationally wicked)

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The Architecture of a Sequencer

• Phred (Phil Green and Brent Ewing)
• Reads DNA sequencer trace data, calls bases,
  assigns quality values to the bases, and writes
  the base calls and quality values to output files
• Phrap (Phil Green)
• A program for assembling shotgun DNA sequence
  data

http//www.phrap.org
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The Architecture of a Sequencer

• Phred
• Use Fourier methods to predict base traces around
  each point
• Examine each trace to find actuals
• Match the predicted traces with actuals
• Evaluate each match according to specific quality
  measures
• Phrap
• Eliminate garbage sequences
• Identify all potentially overlapping pairs of
  sequences (must have an exact match of
  approximately 14 bases and a quality alignment of
  the whole sequence
• Establish scores for pairwise alignment, overlap,
  length, and quality
• Create a candidate merged sequence starting with
  pairs from the highest scores
• Produce a consensus sequence based on voting from
  the quality scores of each base

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The Architecture of SETI_at_home
http//www.computer.org/cise/articles/seti.htm
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The Architecture of the Dead Sea Scrolls Analysis

• Tens of thousands of fragments discovered in 1947
• Study of the scrolls was confined to a small set
  of scholars, who published a concordance to
  assist their analysis
• In 1991, Professor Ben Zion Wacholder of Hebrew
  Union College, and Martin Abegg transferred the
  concordance to a Macintosh, and using matching
  algorithms, generated a complete and relatively
  accurate combined transcript

http//www.judaica.org
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Lessons Learned
Common architectures may be found in uncommon
places
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The Architecture of Autonomous Robots

• Shakey, built in 1969 at SRI, was the first
  significant mobile, autonomous robot
• Shakey should never have been built. There was a
  failure to recognize the deep problems in AI.

• Asimo, built at Honda, is an intelligent,
  two-legged humanoid robot
• Asmio can react to movements, voice, and facial
  expressions

http//world.honda/asimo
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The Architecture of Ghengis

• Rodney Brooks at the MIT AI Lab has explored
  subsumption architectures
• Fast, cheap, and out of control

Brooks, 2002, Flesh and Machines, MIT Press
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The Architecture of a Mindstorms Robot

• Developed by Rationals team in Singapore
• A Rose/RT to Mindstorms connection

http//www.rational.net/content/images/catapulse/p
ublicattachment/doc/8097_ps_2599.doc
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Lessons Learned
The simplest architectures are best
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The Architecture of an Interpreter

• The Altair 8080 was the first really personal
  computer
• Its basic interpreter was written by Bill Gates
  and Paul Allen
• Lots of tricks were required to save memory

Reuben Harris
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The Architecture of Classic Systems

• All legacy systems exhibit sedimentation

http//www.computerhistory.org
Jason Lanier, 2002, The Complexity Ceiling, The
Next Fifty Years
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Lessons Learned
You can learn a great deal from an archeological
dig
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The Architecture of a Web-centric System
Integrated Service Request
App. Server
Company A
Company B
WebServer
App. Server
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The Architecture of a First-Generation System

• Push information in a linear fashion
• HTML-centric
• Architecturally trivial

Siegel, 1996, Creating Killer Web Sites, Hayden
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The Architecture of a Second-Generation System

• Push visitors using simile and hierarchy
• HTML-centric, but more graphical and modestly
  dynamic
• Architecturally simple

Siegel, 1996, Creating Killer Web Sites, Hayden
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The Architecture of a Third-Generation System

• Pull visitors in the door
• Platform-centric
• Architecturally expressive but complex

Siegel, 1996, Creating Killer Web Sites, Hayden
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Demo

• Scenario
• Existing shopping cart website produces invoices
  for online purchases
• Need to update the existing system with a credit
  card web service

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Lessons Learned
An architecture must grow and adapt or die
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The Architecture of Buildings
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Lessons Learned
Sometimes you have to break the foundation
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The Architecture of Buildings
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The Architecture of e-Business
http//www.ibm.com/developerworks/patterns/
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Lessons Learned
The best architectures are full of patterns
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Handbook of Software Engineering

• Working to provide a reference book of common
  architectures across the breadth of
  software-intensive systems
• Artificial intelligence systems Commercial
  systems
• Communications systems Development environments
• Devices Entertainment/sports systems
• Financial systems Industrial systems
• Legal systems Multimedia systems
• Medical systems Military systems
• Operating systems Platforms
• Scientific systems Transportation systems
• Utilities

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Lessons Learned
Fundamentals never go out of style
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The Architecture of Unusual Things

• Everything has an architecture
• The soul of an architecture is found in its
  mechanisms
• Common architectures may be found in uncommon
  places
• The simplest architectures are best
• You can learn a great deal from an archeological
  dig
• An architectures must grow and adapt or die
• Sometimes you have to break the foundation
• The best architectures are full of patterns
• Fundamentals never go out of style

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The driving force behind software engineering is
the rise in levels of abstraction
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Thank You
Grady Booch gbooch_at_us.ibm.com (email) 39.620/-105.
076(GPS)
The Architecture of Unusual Things