BigTable

Google System used for storing data of various Google Products, for instance Google Analytics, Google Finance, Orkut, Personalized Search, Writely, Google Earth and many more
Big table is
- Sparse
- Persistant
- Muti dimensional Sorted Map
It is indexed by
- Row Key: Every read or write of data under single row key is atomic. Each row range is called Tablet. Select Row key to get good locality for data access.
- Column Key: Grouped into sets called Column Families. Forms basic unit of Access Control.All data stored is of same type.Syntax used: family:qualifier
- Time Stamp:Each cell consists of multiple versions of same data which are indexed by Timestamps.In order to avoid collisions, Timestamps need to be generated by applications.
Big Table API: Provides functions for
- Creating and Deleting
  - Tables
  - Column Families
- Changing Cluster
- Changing Table
- Column Family metadata like Access Control Rights.
- Set of wrappers which allow Big Data to be used both as
  - Input source
  - Output Target

Dynamo

Availability is the buzz word for Dynamo. Dynamo=Availability
Shifted Computer Science paradigm from caring about the consistency to availability.