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Application, system and device domain

Short answer

Application domain is the top layer providing user functions; system domain manages OS, communication, and database services; device domain is the physical hardware. They differ in position, role, contents, and concerns, with each depending on the layer below.

Compare among application domain, system domain and device domain.

The three domains are the layers of the global structure of a multimedia system. The application domain is what the user works with, the system domain supplies the operating and communication services, and the device domain is the physical hardware that handles the media.

PointApplication domainSystem domainDevice domain
PositionTop layerMiddle layerBottom layer
Main roleProvide the functions the user wantsManage resources and give services to applicationsCapture, store, transport and present raw media
ContainsApplications, user interface, documents, programming abstractions (API, toolkits, authoring systems)Operating system, communication system, database systemCamera, microphone, scanner, monitor, speaker, storage and network hardware
Seen byEnd user and application developerSystem programmerHardware engineer
Typical concernsUsability, document structure, interaction, synchronisation specificationReal-time scheduling, QoS, protocols, file organisation, media-data retrievalSampling, resolution, bandwidth, capacity, access time
Depends onSystem domain servicesDevice domain hardwarePhysical technology only
ExamplesVideo conferencing, e-learning software, gamesWindows/Linux media scheduler, TCP/IP and RTP, multimedia databaseWebcam, sound card, DVD drive, LCD display
Change affectsOnly that applicationAll applications that use the serviceDrivers in the system domain

Interaction between them

 Application domain  -- requests -->  System domain
 (play lecture video)                 (schedule CPU/disk,
                                       fetch stream)
                                           |
                                           v
                                     Device domain
                                     (decode, display,
                                      play sound)

For example, when a student plays a recorded lecture, the player (application domain) asks the OS to read the file and decode it (system domain), and the display and speakers (device domain) present picture and sound. Layering allows each domain to be improved independently.

Example: video conferencing

  • Application domain: conferencing program with user interface for joining a call, chat window and shared whiteboard.
  • System domain: OS schedules audio and video capture threads, the communication system sends the streams using RTP/UDP with delay control and synchronises sound with lips, and the database may record the meeting.
  • Device domain: webcam, microphone, sound and graphics cards, display, speakers and network card.

Key difference in one line each

  • Application domain answers "what does the user do?".
  • System domain answers "which services and resources make it possible?".
  • Device domain answers "which hardware captures, stores and shows the media?".

✓ Answer checked by Claude Opus 5.5 (high effort)

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