How would you decide whether a system design is a good one?

Some criteria....

• does the design achieve the objectives?
• is it possible to implement the design with the manpower and expertise available?
• is it technically feasible? Does all the hardware exist?
• is the design as simple as possible so people can easily understand how it works? Complex designs are harder to get working and harder to solve problems which arise.
• is it possible to implement it within the time-scale proposed?
• is it possible to implement the design within the budget available?

• Easy to use
• Robust - it should not crash or fail.
• Flexible - it can be easily reconfigured.
• Reliable - it should not fail due to design faults
• Portable - it can be used on different hardware systems
• Easy to maintain - modifications can be easily made.

...and the best way to ensure all of these is with a good design.