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夏合宿 発表20012/8/1
In 山代温泉
前田 経一
What is “The BIG Switch”
MapReduce and Functional Programming
Topics
Nicholas Carr “The BIG SWITCH : Rewiring the World, from Edison to Google”
Buzzword “Cloud” spread by the book.
Electricity From Edison : private power generation To Utility : central electricity generating
systemComputing as well From Private computing To Utility computing
From Edison to Google
Why “Private to Utility”
Urbanization
Independent vs Dependent
Do It Yourself vs Utility
Generalist vs Specialist
Country vs City
MapReduce
Hadoop
Neumann architecture Program & Data
Data → Program Program → Data
Mobile Agent
Data Locality
“The problem is simple: while the storage capacities of hard drives have increased massively over the years, access speeds—the rate at which data can be read from drives— have not kept up. “
Random Access > Sequential Access
Data access speed
map(String key, String value): // key: document name // value: document contents for each word w in value: EmitIntermediate(w, "1");
Map Function
reduce(String key, Iterator values): // key: a word // values: a list of counts int result = 0; for each v in values: result += ParseInt(v); Emit(AsString(result));
Reduce Function
Map and Reduce concepts came from Functional Programming Language.
Reduce Function must have associativity becouse of non-deterministic.
DAG + Operator
MapReduce and Functional Programming