Interface of

1
Interface of The Gridto The Fabric

• Rich Baker
• Brookhaven National Lab

2
Outline

• Overview Definitions
• Fabric vs. Middleware?
• Fabric vs. Grid?
• Refocus the Debate?

3
What are Middleware Fabric?
4
Why Is There Gray Area?

• Multiple Layers of Fabric
• Chip Set, Physical Disks, Raw Hardware
• Operating Systems, File Systems
• Batch Queues
• Site Administration Tools
• Policy, Security
• Multiple Layers of Middleware
• Low Level Services Used by Higher Level Services
• Some Push to Reimplement Fabric Services With
  Grid Aware Services Is This Still Middleware?
• How Low Can (Should) It Go?

5
Can We Draw a Line Between Fabric and Middleware?

• What is the Difference Between a High Level
  Fabric Service and a Low Level Middleware
  Service?
• Site Boundary? But Many Traditional Fabric
  Elements Cross Site Boundaries and Many Important
  Middleware Components Do Not
• Maybe Everything is Middleware? Even an
  Operating System Translates Concrete Services to
  Abstract Services
• The Fabric Cannot be Separated From Middleware
• Not a Useful Distinction

6
Can We Draw a Line Between Fabric and The Grid?

• The Fabric is Part of the Grid
• Site Boundary?
• Many Pure Grid Components Reach Inside Sites
• Grid Awareness?
• Grid Aware Batch Queues or File Systems May
  Coexist With Non-Grid Implementations
• Even Operating Systems Will Be Grid Aware

7
Refocus the Debate?

• Focus on Standard Interfaces/Protocols Between
  Layers?
• Good Middleware Should Provide an Abstract
  Service With Defined Interfaces Without Dictating
  Specific Lower Level Concrete Implementations
• Good Middleware Should Adapt to Multiple Lower
  Level Protocols
• Focus on Who is Responsible for What?
• Site Administrators Have Specific Contractual (or
  Legal) Obligations
• Policy Enforcement and Security are Fundamental
  Site Functions
• Site Administrators Should Have Choices in
  Implementation

8
Grid / Fabric Interface

• Define Interfaces Sites Must Provide
• Interfaces, Not Implementations
• Must be Consistent with Site Policies
• Grid Projects Must Help Develop Implementations
• Middleware that Provides Defined Interfaces On
  Top of Legacy Site Implementations
• When Appropriate, Reimplement Legacy Components
• Develop Grid Security Model Consistent With Site
  Policies
• Will Require Some Compromises by Sites
• Must Be Flexible Enough to Accommodate Variety
• Heterogeneity Must Be Expected!!!