Concept
The clipboard is a buffer that some operating systems provide for short-term storage and transfer within and between application programs. The clipboard is usually temporary and unnamed, and its contents reside in the computer's RAM. The clipboard provides an application programming interface by which programs can specify cut, copy and paste operations. It is left to the program to define methods for the user to command these operations, which may include keybindings and menu selections. When an element is copied or cut, the clipboard must store enough information to enable a sensible result no matter where the element is pasted. Application programs may extend the clipboard functions that the operating system provides. A clipboard manager may give the user additional control over the clipboard. Specific clipboard semantics vary among operating systems, can also vary between versions of the same system, and can sometimes be changed by programs and by user preferences. Windows, Linux and macOS support a single clipboard transaction. Clipboards as buffers for small text snippets were first used by Pentti Kanerva when he used it to store deleted texts in order to restore them. Since one could delete a text in one place and restore it in another, the term "delete" wasn't what one would expect in this case. Larry Tesler renamed this in 1973 as cut, copy, and paste and coined the term "clipboard" for this buffer, since these techniques need a clipboard for temporary saving the copied or cut data. Applications communicate through the clipboard by providing either serialized representations of an object, or a promise (for larger objects). In some circumstances, the transfer of certain common data formats may be achieved opaquely through the use of an abstract factory; for example, Mac OS X uses a class called NSImage to provide access to image data stored on the clipboard, though the actual format of the image data backing the object is hidden.