Introduction

The Sloan Digital Sky Survey utilizes a system of very complex instruments, support systems, and software to achieve its scientific and operational goals.  Participants from a large number of institutions are involved with construction, commissioning, and survey operation. Effective integration of these systems requires a formal method of decision making for change control. This process began by putting existing requirements and specifications documents under change control. As the project progresses and systems and equipment move from construction into operation, instruments, hardware support systems, and project software will all be put under configuration control.

A Change Control Board (CCB) consisting of representatives of the scientific and technical leadership of the project has been established to oversee the change control process. Change requests should be submitted to the Project Manager, who will initiate a meeting of the CCB to consider the request. Decisions of the CCB will be recorded and approved changes will be made. All controlled documents will be posted in HTML on the web.  A list of instruments, support systems, and software under configuration control will also be posted on the web.
 

Configuration Documentation

Documents under formal change control include technical requirements and specifications and will be expanded over time to include other appropriate documents.  At the present time, the following three documents are under formal change control:

1) Scientific Requirements and Scientific Commissioning

2) Requirements and Specifications for the 2.5-Meter Telescope

3) Data Processing Requirements for SDSS Off-line Software

Change Request

Action of the CCB is initiated by a Change Request (via email) to the Project Manager. The Change Request will contain arguments for revising a controlled document or some part of a system or component configuration. The Change Request will be circulated to the CCB by the Project Manager for review and consideration.
 

Change Control Board Meetings

The Project Manager will call a telephone meeting of the CCB to consider a change request and when appropriate, to hear the arguments for change by the requester. Decisions of the CCB will be made by consensus and will be recorded and circulated by the Project Manager.
 

Change Order

If the decision is made to modify a controlled document or a system configuration, the Project Manager will work with the appropriate individuals to initiate the revision process.  If a controlled document is being revised, the modified document will be updated in CVS and posted to the web.  If a system is being modified, the Project Manager and Technical Director will work with the appropriate individuals to establish appropriate acceptance tests to verify that the change was made correctly, satisfies the new requirement, and that the change had no adverse or unanticipated impact on the modified system or any systems which interface with the modified system..
 

The Change Control Board

The Project Scientist will chair the CCB.  In the absence of the Project Scientist, the Project Manager will chair the CCB.  The Project Manager prepares and distributes the agenda for CCB meetings and is responsible for distributing the decisions of the CCB to the appropriate individuals for follow-up action..

The CCB consists of the following members:

Project Scientist - Jim Gunn
Project Manager - Bill Boroski
APO Site Operations Manager - Bruce Gillespie
Head of Survey Coordination - Steve Kent
Head of Data Processing and Distribution - Chris Stoughton
Deputy Project Scientist - Michael Strauss