Chapter 5: MULTIMEDIA DATABASE MANAGEMENT SYSTEM ARCHITECTURE BIT 3193 MULTIMEDIA DATABASE

5.2Client-Server Component Communication Manager Retrieval Schedule Generation Response Handler Interactive Query Formulator

Communication Manager : Manages the communication requirements of a multimedia database client. Its functionalities are the same as that of the server communication manager.

Retrieval Schedule Generator: Determines the schedule for retrieving media objects. For the retrieval schedule generator: ◦ The response handler provides information regarding the objects composing the response and the associated temporal information. The retrieval schedule generator: ◦ Based on the available buffer and network throughput, determines the schedule for object retrieval. This retrieval schedule is used by the communication manager to download media objects in the specified sequence.

Response Handler: Response Handler: Interacts with the client communication manager in order to identify the type of response generated by the server. If the response comprise of the information regarding the object to be presented: ◦ Then the information is passed to the retrieval schedule generator for determining the retrieval sequence. If the response comprise of the information regarding modifying the posed query or a null answer: ◦ The response is passed to the user.

Interactive Query Formulator: Helps a user to frame an appropriate query to be communicated to a database server. This module takes the response from the server (through the response handler module) in order to reformulate the query, if necessary.

5.3Implementation Considerations Hardware Resource Operating System Computer Network

Hardware resources: The available hardware resources influence both client and server design. On the server side: ◦ The available disk space limits the size of a multimedia database that can be handled. ◦ The number of queries that can be handled and the query response time depends, to a certain extent, on the speed of the system. On the client side: ◦ Buffer availability for media objects retrieval is influenced by available hardware sources. ◦ User interface for multimedia presentation is also influenced by hardware characteristics such as monitor resolution, width and height.

Operating System: Multimedia database are composed of continuous media objects. The retrieval and presentations of these media objects have an associated time constraints. Hence, real-time features might be needed as part of the operating system. Also, the file system needs to handle large media objects.

Computer Network: Services offered by computer networks influences the retrieval of media objects by a client system. If guaranteed throughput is not offered by the network service provider, the client may not be able to retrieve object as the required time. This may lead to an object presentations sequence that differs from the temporal requirements specified in the database. Also, the buffer requirements in the clients system depend on the throughput offered by the network service provider.