Non-functional requirements

Non-functional requirements make up the bulk of any Objectives and Requirements Document such as in the Peak Oil Homestead Example. They specify the qualities of the system that will provide the functions we desire. Below are some further non-functional requirements for the Homestead.

Testability:
The homestead shall provide means to test repairs and new components without damage to the sub-systems.
Thinking ahead to what might be broken when trying to test any given repair can save you a lot of grief in the future. For instance, testing a homemade fuse by sticking it in your house fuse box is not the best of ideas. Plan to have standalone test equipment to verify proper functionality.

Extensibility:
The homestead shall include means for future expansion with a minimum of deconstruction.
Plan for future growth of your homestead by using an open architecture that can be added to without major reconfiguration.

Endurability
The homestead shall provide a 12-month supply of all items.
This includes any items that require frequent replenishment such as wood, light bulbs, clothing, food, soap, and so forth.

Security
The homestead shall alert the occupants when humans enter the property.
I could probably do an entire other blog just about Peak Oil security, but I’ll try to keep things pretty general here. This requirement specifies that there should be some sort of an alert system – it could be electronic, mechanical, or animal (e.g. a dog) – that will let the residents know when someone enters their property.

The homestead shall provide means for defense against intruders.
We could be more specific with this requirement, but the above will do for now.

Technology
The homestead shall use technology with a Technology Readiness Level of 7 or greater (per NASA’s TRL definition).
A discussion of TRL’s is found in this post. TRL 7 specifies “System prototype demonstration in operating environment” – this prevents us from reaching toward unproven technology in our homestead designs. Using an item with a low Technology Readiness Level could keep us bogged down in serious complications when we should be focusing on more important aspects of the homestead.