Earth Science Data System Working Group

Software Reuse and Reference Architecture Processes Study

Team:

Gail McConaughy, GSFC
Nadine Alameh, GST
David Isaac, Business Performance Systems/GST
Alan Doyle, consultant/GST (new addition)
Mark Nestler, GST
TBD, ESISS named representative

Analysis Approach

NewDISS Retreat

November 7-8, 2001

DRAFT, version 4

Questions to be Addressed:

Will actively promoting and investing in reuse and/or reference architectures provide the following return on investment?
1. Reduction of the cost of supporting future missions, science, and applications
2. Increased flexibility and responsiveness to new missions, science and applications
3. Increased effective, accountable community participation in system development and operations
If it will, what processes would best move ESE toward that goal? How can the community and NASA team to implement those processes?

Motivation
The Problem	The Opportunity
Need a more cost effective DISS development approach for future missions Current missions consume most of the projected ESE information systems budget "Expertise" large factor in cost effective development leverage required	Reuse and reference architectures can reduce system development costs Reuse can leverage large base of existing ESE software, system assets and expertise Reused artifacts and components require less development and testing Reference architectures can enable an efficient market of components and services
Need a more flexible/responsive development approach Very large development efforts require rigid requirements control Incompatible and missing components	Reuse and reference architectures can improve flexibility & responsiveness Smaller contracts can be effectively coordinated through the ref. Architecture Assembly of new systems from reused or commodity components shortens schedules
Need increased and effective/accountable community participation Centralized systems may not effectively leverage community expertise Community systems may not effectively leverage each other or meet critical mission requirements (e.g., long-term data retention)	Reference architectures can increase community participation Enables development to be performed wherever expert resources are available Ensures interoperability of independently developed components & systems Provides a clear demarcation for delivered functionality

Study Approach

Reliance on stakeholder view of supply and demand emphasis on practical experience of actual mission to mission reuse
Key related initiatives examined for recommendations e.g. Carnegie Mellon SEI, OGC, OMG, ETC.
Feedback incorporated from ESE scientific community through quarterly workshops

Information Sources

Other formulation team studies
Related NASA initiatives, including the Digital Earth Reference Model, the Systematic Software Reuse Reference Model, the Earth Science Modeling Framework, and the Information Power Grid
Current ESE systems, including ECS, TSDIS, SeaWiFS, ESIPS, DAACs, MODAPS, LaTIS, Landsat-7, OMI, ECHO, EDG, CEOS, GCMD, DIAL, and Quickscat/SeaWinds
Future mission science systems, including those for the Global Precipitation Mission, NPOES Preparatory Project, Landsat Data Continuity Mission, Ocean Surface Topography, Ocean Vector Winds, Solar Irradiance Gap Filler Mission, Total Column Ozone, and Global Carbon Cycle Initiative
Related consortia including the OGC, FGDC, OMG, and CCSDS
Software engineering groups including the CMU Software Engineering Institute, the GSFC Software Engineering Laboratory, and the Community Climate System Model System Engineering Group
Software reuse initiatives including COSMO, Software Technology for Adaptable, Reusable Systems (STARS); and HP Systematic Software Reuse and Component-Based Software Engineering
Architecture framework initiatives including the Federal Enterprise Architecture Framework, the C4ISR Architecture Framework, and the Zachman Framework
Government organizations facing similar challenges, including NOAA, USGS, NIMA, NRO, and DOE

(Emphasized items indicate initial discussions held or case study identified)

Motivation

Interfaces to Other ESDSWG Studies: Requests

Standards and Interfaces (for Near-Term and Long-Term Missions)
- Collaboration and Coordination
  - This study to focus on "software interfaces"
  - Assume "data flow" interfaces across organizational boundaries examined by other study
Costing Study
- Inputs from Costing Study: LOC sizing at the component level, component and process gap
- Collaboration with the Costing Study: Sensitivity analysis of "one-off" vs. "development from scratch" with presumed reuse savings factor

Working Definitions (Backup)

Reuse

Reuse is the act of taking a functional capability used in (or provided by) one system or mission and employing it in another system or mission. This broad definition is intended to encompass a variety of techniques that have the potential to reduce future DISS costs, not simply libraries of reusable software components. For example, employing an entire existing system (including software, hardware, and operational processes) to support a new mission would fit this definition of reuse.
Architecture is defined as the structure of components, their interrelationships, and the principle guidelines governing their design and evolution over time (i.e., components, connections, and constraints).
A reference architecture is a generic architecture that provides coherent design principles for use in a particular domain (in this case, Earth science). It aims at structuring the design of specific system architectures by defining a unified terminology, a generic system structure, the kinds of system components, their responsibilities, dependencies, interfaces, data, behaviour (interactions), constraints, design rules, and models to represent all these aspects.
A software product line is a set of software-intensive systems sharing a common, managed set of features that satisfy the specific needs of a particular market segment or mission and that are developed from a common set of core assets in a prescribed way. (Carnegie Mellon SEI)

ESDSWG: Strategic Evolution of ESE Data Systems

(Formerly NewDISS: New Data and Information Systems and Services)