API (Application Programming Interface)
An application programming interface (API) is a set of routines, data structures, object classes and/or protocols provided by libraries and/or operating system services in order to support the building of applications.[1] An API may be:
Language-dependent; that is, available only in a particular programming language, using the particular syntax and elements of the programming language to make the API convenient to use in this particular context.
Language-independent; that is, written in a way that means it can be called from several programming languages (typically an assembly/C-level interface). This is a desired feature for a service-style API that is not bound to a particular process or system and is available as a remote procedure call.
The API itself is largely abstract in that it specifies an interface and controls the behavior of the objects specified in that interface. The software that provides the functionality described by an API is said to be an implementation of the API. An API is typically defined in terms of the programming language used to build an application. The related term, ABI (Application Binary Interface), is a lower level definition concerning details at the Assembly language level. For example, the Linux Standard Base is an ABI, while POSIX is an API.[2]
The API acronym may sometimes be used as a reference not only to the full interface but also to a single function or even a set of multiple APIs provided by an organization. Thus the scope is usually determined by the person or document that communicates the information.
API examplesBelow are listed some well-known APIs.
The PC BIOS call interface
Comedi Data Acquisition API
Single UNIX Specification (SUS)
Windows API
The various Java Platform Edition APIs (Micro, Standard, Enterprise)
ASPI for SCSI device interfacing
Carbon and Cocoa for the Macintosh OS
iPhone API
OpenGL cross-platform 3D graphics API
DirectX for Microsoft Windows
Simple DirectMedia Layer (SDL)
Google Maps API
MediaWiki API
YouTube API
PayPal Payment Pro
Facebook API (Facebook)
Drupal API (Drupal)
Source:
http://en.wikipedia.org/wiki/API-----------------------------------------------------------------------------------------------------
SDK (Sowtware Development Kit)A software development kit (SDK or "devkit") is typically a set of development tools that allows a software engineer to create applications for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar platform.
It may be something as simple as an application programming interface (API) in the form of some files to interface to a particular programming language or include sophisticated hardware to communicate with a certain embedded system. Common tools include debugging aids and other utilities often presented in an integrated development environment (IDE). SDKs also frequently include sample code and supporting technical notes or other supporting documentation to help clarify points from the primary reference material.
A software engineer typically receives the SDK from the target system developer. Often the SDK can be downloaded directly via the Internet. Many SDKs are provided for free to encourage developers to use the system or language. Sometimes this is used as a marketing tool. For example, Foo Products might provide the Widget SDK for free to encourage people to use it. In turn, more people will be encouraged to buy more of their widgets since they can program them for free.
SDKs may have attached licenses that make them unsuitable for building software intended to be developed under an incompatible license. For example, a proprietary SDK will likely be incompatible with free software development, while a GPL licensed SDK will likely be incompatible with proprietary software development. LGPL SDKs are typically safe for proprietary development.
An SDK for an operating system add-on (for instance, QuickTime for Mac OS) may include the add-on software itself, to be used for development purposes, if not necessarily for redistribution. An interesting situation arises here between platforms where it is possible to develop applications that can at least start up on a system configuration without the add-on installed, and use a Gestalt-style run-time environment query to determine if the add-on is present, and ones where the application will simply fail to start. In other words, it is possible to build a single binary that will run on configurations with and without the add-on present, albeit operating with reduced functionality in the latter situation.
Providers of SDKs for specific systems or subsystems may sometimes substitute a more specific term instead of software. For instance, both Microsoft and Apple provide driver development kits (DDK) for developing device drivers.
Source:
http://en.wikipedia.org/wiki/Software_Development_Kit-------------------------------------------------------------------------------------------------
APK ( Android Package )An .apk file extension denotes an Android Package (APK) file. This file format is used for the distribution and installation of bundled components onto the Android mobile device platform.[1][2]
The MIME media type for .apk is application/vnd.android.package-archive.[3]
Source:
http://en.wikipedia.org/wiki/APK_(file_format)
---------------------------------------------------------------------------------------------------
