System Design for Home Automaton Design Goals Performance

System Design for Home Automaton

Design Goals • Performance Criteria – Server prioritizes client requests to provide quick response time to critical requests. • E. g. Device state changes supersede image transfers. – Client is multi-threaded to allow simultaneous server communication and user interaction. Server is a single-threaded state machine. – One zone will be held in memory at any given time to limit memory consumption.

Design Goals • Dependability Criteria – Errors in server connection will be reported to the user. – Requests are given an encrypted identifier. Server reports success or failure to client with identifier. – Out-of-order transmissions generate errors and the connection is terminated to handle packet spoofing.

Design Goals • Cost Criteria – Open-source; free for all. Yee-Ha! • Maintenance/Extendability Criteria – Extendable to multiple device types. – Server will be able to communicate with a client on any platform. • End User Criteria – Easy point-and-click user interface.

System Decomposition

Hardware/Software Mapping • Client – C#, Open GL • Server – C++ • Protocol – TCP/IP Sockets

Persistent Data Management • Zones will be stored in data files managed by data structures. • Users will be stored in a data file on the server • Server configuration will also be stored in a data file

Access Control • There are two types of users: Administrator and Occupant. • Administrator has full access to all features of the client and server. • Occupant has access only to change device states. • Both user types are authenticated with a username and password.

Software Control • The server will operate on a proceduredriven state machine with a singlethreaded loop handling all input/output and device control operations. • The client will operate on an event-driven model with multiple threads (GUI & Network)

Boundary Conditions • Establish Server Connection – User is authenticated. All devices (real and virtual) and the image file for the root zone are downloaded to the client • Disconnect From Server – Server request queue is flushed and executed, while errors are reported to the client.

Boundary Conditions • Connection Unexpectedly Terminated – Server processes all requests in its queue and stores errors in a log file. – Client reports an error to the user and offers to reconnect. Upon reconnection, Client will be updated with the current devices states.