1. HSA Reusability Issues1

2. “Appliance” Functions
ECS
Accept & validate orders from ECS
Schedule order execution
Order input data from ECS
Process data
Deliver results to ECS
Order status and control (optional)
Queue
SAM
HSA
Input
Output
ECS 2

3. Scheduling & Resource Management
“Disk space” is the only managed resource
T-REX rejects overlarge orders (too big to ever be processed)
FETCH manages input and output space
T-REX asks FETCH if there’s enough space to start an order now
If there’s not enough space, the order is bypassed and priority is incremented
If a new appliance requires additional resources to be managed, much of HSA will have to be rewritten 3

4. Accept & Validate Orders
ECS
Handled by T-REX
Most likely reusable:
ECS interface
Order queue management
HEW-Specific:
Validation criteria
Status recording
T-REX
Queue
SAM
Input
Output
ECS 4

5. Schedule Order Execution
ECS
Handled by T-REX & FETCH
Most likely reusable:
T-REX/FETCH interface
HEW-specific:
Restart/recovery mechanism
T-REX & FETCH
Queue
SAM
Input
Output
ECS 5

6. Order Data from ECS Handled by FETCH Most likely reusable:
ECS interface
Disk resource management
Queue
SAM
FETCH
Input
Output
ECS 6

7. Process Data Handled by REX/HEW Most likely reusable: HEW-specific:
ECS
Handled by REX/HEW
Most likely reusable:
External interfaces to other components
HEW-specific:
REX/HEW interface
HEW
Queue
SAM
REX & HEW
Input
Output
ECS 7

8. REX/Appliance Details
REX’s job is to sequence operations
Accepts orders from T-REX
Orders data via FETCH
Invokes appliance
Delivers data via RALPH
Provides status to T-REX as needed
FETCH
T-REX
RALPH
REX
Appliance
Input
Output 8

9. Deliver Results to ECS Handled by RALPH Most likely reusable:
RALPH/ECS interface if ECS distribution is desired
REX/RALPH interface
FETCH/RALPH interface
May require changes:
If other delivery mechanisms required
Queue
SAM
Input
RALPH
Output
ECS 9

10. Order Status and Control
ECS
Handled by SAM
Most likely reusable:
Interface mechanism
Status messages
HEW-specific:
Control messages
Operator interface
T-REX
Queue
SAM
FETCH
Input
RALPH
Output
ECS 10

11. Adding New Appliances UAH tasks DAAC tasks
Identify components that need to be changed
Document components and interfaces
DAAC tasks
Replace validation code in T-REX
Replace REX/HEW interface
Plug in new appliance
UAH should work with DAACs to
Provide technical support on HSA software
Update HSA software based on lessons learned to make adaptation process easier next time 11

12. Multiple Appliances Option #1
User request
ECS
Registry
ECS uses registry to select service
Each service runs on a separate system or in a separate account
Each service has a unique copy of T-REX FETCH, and RALPH
Disk space is dedicated to each service
T-REX
T-REX
REX+
REX+
Input
Output
Input
Output
FETCH
RALPH
FETCH
RALPH 12

13. Multiple Appliances Option #2
ECS uses registry to select service
Multiple services run on same system in same account
Separate T-REXs
Common FETCH and RALPH
Disk space is shared
Difficult to implement: Changes required in T-REX, FETCH, & RALPH
User request
ECS
Registry
T-REX
T-REX
REX+
REX+
Input
Output
FETCH
RALPH 13

14. Multiple Appliances Option #3
User request
ECS
Registry
ECS uses registry to augment order with service information
Single T-REX uses order info to route orders to REXes
Single FETCH and RALPH handle I/O
Disk space is shared
T-REX
REX+
REX+
Input
Output
FETCH
RALPH 14