System requirements
Functional:
List functional requirements for the system (Ask the chat bot for hints if stuck.)...
- cars can go into the parking lot, get a ticket, park in the spot
- keep track of open spots
- keep track of the type of spots (disability, compact, electrics, normal)
- keep track of cars that enter and exit
- keep track of costs per hour (enter and when exit times)
Non-Functional:
List non-functional requirements for the system...
- Consistency: ensure parking availability of the space
- Availability: having it open at all times to enter and exit
- Latency: not as important, can a few seconds at kiosks
- Scalability: national usage, 50 states, 5 per state, 250 garages in total
Capacity estimation
Estimate the scale of the system you are going to design...
Storage:
250 garages
5 floors
100 spots
100 * 5 * 250 =125,000 spots in total
1MB of data for each spot
125,000 * 1 = 125,000 MB
Bandwidth:
125,000 * 100 * 2 = 250,000,000 requests per day
API design
Define what APIs are expected from the system...
REST
PUT garage/parkingspaceid/entering
paramaters:
garageid
parkingspaceid
timestamp
carid
GET garage/availablespace/spacetype
parameter:
garageid
spacetype
return:
garagid
parkingspaceid
PUT garage/parkingspaceid/exiting
parameters:
garageid
parkingspaceid
timestamp
carid
return
price
Database design
Defining the system data model early on will clarify how data will flow among different components of the system. Also you could draw an ER diagram using the diagramming tool to enhance your design...
relational database
garage table:
garageid: unique indentifier
spots table:
garage_id: foreign key
spot_id: unique identifier
time_stamp: string
spot_type: string (handicapped, normal, compact, electric)
occupied: boolean
High-level design
You should identify enough components that are needed to solve the actual problem from end to end. Also remember to draw a block diagram using the diagramming tool to augment your design. If you are unfamiliar with the tool, you can simply describe your design to the chat bot and ask it to generate a starter diagram for you to modify...
Request flows
Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...
Detailed component design
Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...
Trade offs/Tech choices
Explain any trade offs you have made and why you made certain tech choices...
Failure scenarios/bottlenecks
Try to discuss as many failure scenarios/bottlenecks as possible.
Future improvements
What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?