Computing platform means in general sense, where any piece of software is executed. It may be the hardware or OS, even a web browser as long as the code is executed in it.
The term computing platform can refer to different abstraction levels, including a certain hardware architecture, an operating system (OS), and runtime libraries. In total it can be said to be the stage on which computer programs can run.
A platform can be seen both as a constraint on the application development process, in that different platforms provide different functionality and restrictions; and as an assistance to the development process, in that they provide low-level functionality ready-made. For example, an OS may be a platform that abstracts the underlying differences in hardware and provides a generic command for saving files or accessing the network.
Platforms may also include:
Hardware alone, in the case of small embedded systems. Embedded systems can access hardware directly, without an OS; this is referred to as running on "bare metal".
A browser in the case of web-based software. The browser itself runs on a hardware+OS platform, but this is not relevant to software running within the browser.
An application, such as a spreadsheet or word processor, which hosts software written in an application-specific scripting language, such as an Excel macro. This can be extended to writing fully-fledged applications with the Microsoft Office suite as a platform.
Software frameworks that provide ready-made functionality.
Cloud computing and Platform as a Service. Extending the idea of a software framework, these allow application developers to build software out of components that are hosted not by the developer, but by the provider, with internet communication linking them together. The social networking sites Twitter and facebook are also considered development platforms.
A virtual machine (VM) such as the Java virtual machine. or .NET CLR. Applications are compiled into a format similar to machine code, known as bytecode, which is then executed by the VM.
A virtualized version of a complete system, including virtualized hardware, OS, software and storage. These allow, for instance, a typical Windows program to run on what is physically a Mac.
Some architectures have multiple layers, with each layer acting as a platform to the one above it. In general, a component only has to be adapted to the layer immediately beneath it. For instance, a Java program has to be written to use the Java virtual machine (JVM) and associated libraries as a platform, but does not have to be adapted to run for the Windows, Linux or Macintosh OS platforms. However, the JVM, the layer beneath the application, does have to be built separately for each OS.
AmigaOS, AmigaOS 4
FreeBSD, NetBSD, OpenBSD
Linux
Microsoft Windows
OpenVMS
Classic Mac OS
macOS
OS/2
Solaris
Tru64 UNIX
VM
QNX
Android
Bada
BlackBerry OS
Firefox OS
iOS
Embedded Linux
Palm OS
Symbian
Tizen
WebOS
Windows Mobile
Windows Phone
Binary Runtime Environment for Wireless (BREW)
Cocoa
Cocoa Touch
Common Language Infrastructure (CLI)
Mono
.NET Framework
Silverlight
Flash
AIR
Java platform
Java ME
Java SE
Java EE
JavaFX
JavaFX Mobile
LiveCode
Microsoft XNA
Mozilla Prism, XUL and XULRunner
Open Web Platform
Oracle Database
Qt
SAP NetWeaver
Shockwave
Smartface
Universal Windows Platform
Windows Runtime
Vexi
Ordered roughly, from more common types to less common types:
Commodity computing platforms
Wintel, that is, Intel x86 or compatible personal computer hardware with Windows operating system
Macintosh, custom Apple Computer hardware and Classic Mac OS and macOS operating systems, originally 68k-based, then PowerPC-based, now migrated to x86
Newton devices running the Newton OS, also from Apple
ARM architecture used in mobile devices
Gumstix or Raspberry Pi full function miniature computers with Linux
x86 with Unix-like systems such as Linux or BSD variants
CP/M computers based on the S-100 bus, maybe the earliest microcomputer platform
Video game consoles, any variety
3DO Interactive Multiplayer, that was licensed to manufacturers
Apple Pippin, a Multimedia player platform for video game console development
RISC processor based machines running Unix variants
SPARC architecture computers running Solaris or illumos operating systems
DEC Alpha cluster running OpenVMS or Tru64 UNIX
Midrange computers with their custom operating systems, such as IBM OS/400
Mainframe computers with their custom operating systems, such as IBM z/OS
Supercomputer architectures
