Interface (computing)

The interface or the interface ( [ ɪntəfeɪs ] or [ ɪnt̬ɚfeɪs ], English for interface ) is the part of a system, which is used for communication.

The term originally comes from the natural sciences and refers to the physical phase boundary between two states of a medium. He describes pictorially the property of a system as a black box, of which only is the " surface " visible, and therefore only about a communication is possible. Two adjacent black boxes can communicate with each other only if their surfaces " fit together ".

In addition, the word "intermediate layer": The two involved Boxes, it is irrelevant how the other internally bypasses with the messages, and how the answers come out about. The description of the border is part of themselves, and the black boxes just need to know them facing page to ensure communication. This corresponds to the Latin word origin inter, between ' and facies, appearance ', ' form ' for english face, face '.

If you look at any ' system ' as a whole, which need to be analyzed, it will cut this whole system into subsystems. The ' points ' that act as contact points or starting points between these subsystems ( = over which communication takes place), then put the interfaces dar. Using these interfaces, you can assemble the subsystems back to a larger whole.

• 3.1 interfaces for inter-process communication
• 3.2 Interfaces for program components
• 3.3 See also

• 5.1 Unifying device
• 5.2 connection or disconnection point

Basics

The exchange of information takes the form of physical (eg Voltage, amperage ) or logical variables ( data) and can be done (eg parallel port of the PC ) analogue ( eg microphone to a sound card ) or digital. Are not referred to as an interface general mechanical connecting elements of design theory, which serve the communication of information (such as cables or springs).

We distinguish:

• Data interface ( 'data interface' ) - data as interfaces between programs
• Machine interface - interfaces between physical systems
• Hardware interface (hardware interface) - interfaces between physical systems of computer technology
• Network interface ( network interface ) - interfaces between network components
• Software interface ( software interface) - interfaces between programs themselves, the operating system, agreement of methods in object -oriented programming, etc.
• User interface ( user interface) - interfaces between man and machine.
• ' Common Interface ' ( common interface ) for DVB reception devices

An interface is described by a set of rules, the interface description. In addition to describing what functions are available and how they are used, is one of the interface description is also known as a contract that describes the semantics of each function.

Standardized interfaces offer the advantage that components or modules that support the same interface can be interchanged, that is, they are compatible with each other.

It often happens that two parties to the communication must have different but matching interfaces (compatibility, for example, male - female ).

The term interface is also used in project management in the plant, which interfaces describe the interaction between various trades to achieve the required functionality of a system.

Machine interface

Machine interface is the location where a device or a machine interacting with an additional unit or with a further machine. Such an interface will be described as follows.

Physical data

Mechanical parameters:

• Geographical location ( longitude, latitude, altitude, based on a determined reference point)
• Dimensions (length, width, height, if applicable, other dimensions of the mechanical interface, such as hole spacing or diameter for mounting )
• Connecting elements ( type and location )
• Required forces and moments to ensure a static determinacy of the system (eg, tightening torques for screws, rivets )
• Position of the points of force application (eg foundation recordings, scaffolding, carrier )
• Dynamic loads (eg vibrations, explosions )
• Pressures ( max., min., In hydraulic, pneumatic, possibly with funding)
• For material handling (also air or liquids): type of material and quantity per unit of time ( min., max. )
• Non-electrical forms of energy at the interface ( pneumatics, hydraulics).

Electrical parameters:

• Location and type of the electrical connection (s)
• Electric voltage ( min., max. )
• Electric current ( min., max. )
• Further, necessary information on management data (type and cross-section), grounding
• System parameters of electric controls.

Thermal parameters:

• System temperatures ( max., min. )

Chemical data

• Required material properties of the materials of construction of the original system and the systems to be connected
• If necessary properties to be conveyed material

Hardware interfaces

Hardware interfaces are interfaces between physical systems in electrical engineering and electronics.

Hardware interfaces are widely used in computer technology. Industry standards for instance, ensure that a PC is an open system that can be assembled from components from different manufacturers. Examples of hardware interfaces that are used in computers, the PCI bus, AGP, SCSI, USB, Firewire and the older EIA- 232 (also known as RS- 232 or V24).

One distinguishes between parallel and serial (hardware ) interface, depending on whether a plurality of bits can be transmitted at the same time (see the parallel data transfer). In the context of computer peripherals for the IEEE 1284 connector is meant by parallel interface in general, which is mostly used for the printer; is referred to as a serial interface of the obsolete EIA -232 interface, in this context.

In electrical engineering, each connecting analog or digital devices results when meeting an interface. At each intersection of the resistor Ra of the source output is connected to the input resistance Ri of the load adjustment damper which is also referred to as interface damping. The important attenuation factor for this adaptation attenuation at the interface between the power amplifier is particularly to be observed to the speaker; the latter is only voltage adjustment with Ri ' Ra as with all links in audio engineering. Connecting a microphone to the input of a sound card, provides an interface with the problems of return loss as well, the connection of a power amplifier to the loudspeaker. The compound of digital devices Ri = Ra has to be selected so as to avoid unwanted and disturbing reflection of pulses. It is irrelevant that this condition happens to coincide with that for power adjustment.