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Clipboard
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A clipboard is a thin, rigid writing board with a clip at the top for holding paper in place. A clipboard is typically used to support paper with one hand while writing on it with the other, especially when other writing surfaces are not available. The earliest forms were patented in 1870–1871 and referred to as board clips.[1] Another early version of the clipboard, known as the "memorandum file", was invented by American inventor George Henry Hohnsbeen in 1921, for which he was granted U.S. patent 1,398,591.[2] Related to the clipboard is the Shannon Arch File, which was developed around 1877.[1]
Variations
[edit]Clipboards can be constructed from a variety of material, including but not limited to, hardboard, aluminum, PVC, polypropylene, High Impact Polystyrene, and Foamex. Clipboards generally come in two different designs—single or folding. Single clipboards are the more traditional type and consist of a single piece of rigid material and some sort of fixing mechanism along the top. Folding clipboards are usually constructed from a single piece of flexible PVC with two rigid materials enclosed within. A folding hinge connects the two sections to allow the front to be folded over the content to provide protection and often to allow some sort of promotional print or instructions. Folding clipboards also provide additional benefits because of the extra space available, allowing the incorporation of pen holders and pockets for storage.[3] The arrival of the microprocessor and Internet age gave rise to high-tech variants of the traditional clipboard, the first being the Ferranti Market Research Terminal that retained a clip, to hold A4 paper sheets (looking like a large clipboard) but recording answers to questions in its electronic memory.[4][5]
Storage clipboards
[edit]
Storage clipboards have one or more compartments designed for paperwork, both to allow for easy transport of needed papers, and to protect those papers. They may also feature one or several compartments for writing implements.[6] Some versions feature a hinged panel to slide between portions of a two-sided multi-part form.
References
[edit]- ^ a b "Early Filing Devices: Small Files & Filing Devices". Early Office Museum.
- ^ Neo (13 January 2017). "Who invented the Liquid Soap Dispenser". Who Invented First. Archived from the original on 3 December 2022. Retrieved 20 September 2022.
- ^ "Clipboards".
- ^ G. Rowley, K. Barker, V. Callaghan (1986) "The Market Research Terminal & Developments in Survey Research", European Journal of Marketing, Vol. 20 Issue: 2, pp. 35–39.
- ^ Deborah A Martell, "Marketing Information and New Technology", Chapter 8 in the book, Management Information Systems: The Technology Challenge, edited by Nigel Piercy, published by Nichols Publishing Company, New York, ISBN 0-89397-260-6, p. 163, 1987.
- ^ Webster, Chris (2016). Field Archaeologist's Survival Guide : Getting a Job and Working in Cultural Resource Management. London. ISBN 978-1-315-42844-4. OCLC 1058313718.
{{cite book}}: CS1 maint: location missing publisher (link)
External links
[edit]
Media related to Clipboards at Wikimedia Commons
The dictionary definition of clipboard at Wiktionary
Clipboard
View on Grokipediafrom Grokipedia
In computing, the clipboard is a temporary buffer provided by the operating system for short-term storage of data that has been copied or cut from one application or document, enabling it to be pasted into another location or program.[1][2] This mechanism facilitates seamless data transfer across applications, supporting operations like cut, copy, and paste without requiring direct file handling or inter-process communication beyond the system level.[3]
The clipboard operates as a shared resource accessible to all running applications, storing data in specific formats defined by the operating system or registered by programs.[1] Common standard formats include text (CF_TEXT), bitmaps (CF_BITMAP), and enhanced metafiles (CF_ENHMETAFILE), while custom formats can be registered for specialized data like proprietary document structures.[4] In practice, when a user copies content, the source application places it on the clipboard using API calls, and the destination application retrieves it upon paste, often converting formats as needed for compatibility.[1] Operating systems like Windows implement this through Win32 clipboard functions, macOS via the NSPasteboard class for handling multiple types including text and images, and web browsers through the Clipboard API for secure, permission-based access in modern applications.[1][5][2]
Beyond basic functionality, the clipboard has evolved to include features like history tracking in contemporary systems, allowing users to store and recall multiple copied items rather than overwriting with each new operation.[6] For instance, Windows 10 and later versions maintain a clipboard history limited to 25 entries, accessible via keyboard shortcuts, with options to pin frequently used items for persistence, and as of macOS 26 Tahoe (2025), clipboard history is integrated into Spotlight for searching and accessing previous copies.[6][7] This enhancement improves productivity by reducing repetitive copying, though it raises privacy considerations since the clipboard's open nature allows any application to read or modify its contents, potentially exposing sensitive data like passwords or personal information.[1] Third-party clipboard managers extend these capabilities further, offering advanced organization, search, and synchronization across devices, but users must select reputable tools to mitigate security risks.[8]
Overview
Definition and Purpose
A clipboard is a temporary buffer in an operating system's memory that holds data copied or cut from one location for subsequent pasting into another.[1] It serves as a shared intermediary for inter-application data exchange, allowing seamless transfer without direct file operations or re-entry.[9] The primary purpose of the clipboard is to facilitate efficient data manipulation across applications, reducing the need for manual re-entry or intermediate file saving.[3] By providing a centralized, accessible repository, it enhances user productivity through support for diverse formats such as text, images, and files.[10] This mechanism streamlines workflows in everyday computing tasks, such as editing documents or browsing content. Common use cases include copying text from a web browser to a word processor or duplicating images between graphics editors, all enabled by basic operations like copy, cut, and paste.[11]Basic Operations
The basic operations of the clipboard center on the copy-cut-paste cycle, enabling users to transfer selected data within or between applications efficiently. These actions are universally supported across major operating systems and applications, typically accessible via keyboard shortcuts, menu options, or context menus.[2] The copy operation duplicates the selected content—such as text, images, or files—and stores it in the clipboard without altering the original source. On Windows, this is executed using the keyboard shortcut Ctrl+C, or by selecting Copy from the Edit menu or a right-click context menu.[6] On macOS, the equivalent shortcut is Command+C, with similar menu options available.[12] This places the data in a temporary buffer ready for pasting elsewhere.[2] In contrast, the cut operation removes the selected content from its original location and transfers it to the clipboard, effectively moving it. Windows users invoke this with Ctrl+X, while macOS employs Command+X; both platforms also offer Cut via the Edit menu or right-click menu.[6][13] Unlike copy, cut modifies the source directly, making it suitable for relocating data without duplication.[2] The paste operation retrieves the clipboard's contents and inserts them at the target location, such as a cursor position in a document or field. This can be repeated multiple times across sessions until the clipboard is overwritten by a new copy or cut. Standard shortcuts include Ctrl+V on Windows and Command+V on macOS, alongside Paste options in the Edit menu or context menus.[6][12] Paste behavior depends on the application's support for the clipboard's data format, but it generally preserves the original structure.[2] In fundamental clipboard implementations, the system maintains a single active item, where each subsequent copy or cut replaces the existing contents entirely, limiting users to one transferable item at a time.[6][14] These conventions ensure consistent interaction across diverse software environments.[13]History
Origins in Early Computing
The concept of a clipboard in computing originated in text-based systems during the 1960s, where temporary buffers allowed users to store and retrieve deleted or copied text snippets. One of the earliest implementations appeared in TECO (Text Editor and Corrector), developed by Dan Murphy at MIT starting in 1962 for the PDP-1 computer.[15] TECO's "kill" command (e.g., k or numbered variants like 2k to delete two lines) moved selected text to a buffer rather than permanently erasing it, while text could be stored to the buffer using enhancements like the x command and retrieved with g to insert at the current position, enabling reuse of text blocks.[16] These operations provided a foundational mechanism for text manipulation in command-line environments, treating the buffer as a simple, volatile storage area akin to a physical scrap of paper.[15] This buffering approach evolved in early Unix editors, culminating in the vi editor created by Bill Joy in 1976 at the University of California, Berkeley, as a visual interface to the ex line editor.[17] Vi retained and expanded TECO-inspired commands, with "yank" (y or yy for lines) copying text to numbered registers or the default buffer without deleting it, and "put" (p) inserting the yanked content after the cursor.[18] Derived from the ed editor's named buffers (dating to 1971), vi's system allowed multiple storage slots for complex edits, shifting from TECO's single-buffer model to more flexible, register-based temporary storage.[17] These command-line tools emphasized efficiency in batch-oriented computing, where buffers served as intermediaries for relocating code or data without file rewrites. The transition to graphical interfaces began at Xerox PARC in the early 1970s with the Alto computer, where researchers introduced visual metaphors for buffering. In 1973, Larry Tesler joined PARC and, collaborating with Tim Mott, developed the Gypsy word processor (1974–1975) on the Alto, implementing the first cut/copy/paste operations as modeless commands.[19] Users selected text via mouse drag or double-click, then used "cut" to move it to a hidden buffer (with undo support) or "copy" to duplicate it, followed by "paste" to insert at a new location—extending earlier two-step moves from systems like TVEDIT.[19] Gypsy's buffer acted as an invisible "scrap" for text and simple graphics, prioritizing user-friendly interaction over modal commands.[19] Key milestones marked the clipboard's commercialization: the 1981 Xerox Star workstation, the first office GUI system, integrated clipboard-like "transfer" functionality with move, copy, and delete commands, allowing bit-mapped objects to be buffered and pasted across applications via a consistent menu.[20] This built on Alto innovations but added multi-format support for documents and icons in a networked environment.[21] The 1984 Apple Macintosh then popularized these concepts for consumer use, introducing a dedicated Clipboard desk accessory that stored the last cut or copied item (text, graphics, or sounds) in a volatile buffer, accessible system-wide via Command-key shortcuts.[22] Unlike prior single-register systems, the Macintosh's buffer evolved toward interchangeable formats, bridging command-line simplicity with graphical versatility and influencing subsequent GUI designs.[22]Evolution in Graphical User Interfaces
The clipboard emerged as a standardized system-wide service in graphical user interfaces during the 1980s, facilitating seamless data transfer between applications. In 1984, Apple introduced the Macintosh with System Software 1.0, which featured a dedicated Clipboard for holding cut or copied text and images, allowing users to paste content within the same document or across different applications and desk accessories while retaining basic formatting attributes.[23] This innovation enabled intuitive inter-application integration, such as transferring a picture from MacPaint to a MacWrite report, and the Clipboard contents persisted in memory (or spilled to disk if large) until overwritten by a new cut or copy operation.[24] Microsoft followed suit in 1985 with Windows 1.0, incorporating a clipboard supporting basic cut, copy, and paste operations for text and simple graphics, limited by available memory, marking the first graphical shell for MS-DOS with mouse-driven data exchange.[25] These early implementations built on command-line precursors by providing a visual, shared buffer accessible via the Edit menu, promoting cross-application workflows in a nascent GUI ecosystem. The 1990s saw significant expansions in clipboard capabilities to handle richer data types. Support for Rich Text Format (RTF), introduced by Microsoft in 1987 alongside Word 3.0, was enabled in the Windows clipboard through application registration, allowing formatted text with styles like bold and italics to be transferred between compatible programs starting in the late 1980s.[26] Similarly, Bitmap (BMP) format integration, via the CF_BITMAP or CF_DIB standard clipboard formats, enabled image copying from the outset but gained prominence in the 1990s for supporting device-independent bitmaps in tools like Paint.[26] File transfers were added as a format, while Object Linking and Embedding (OLE), released in 1990 as an evolution of Dynamic Data Exchange, permitted embedding editable objects—like spreadsheets within documents—directly through the clipboard, enhancing compound document creation.[27] In parallel, the open-source X Window System diverged with its multi-selection model outlined in the Inter-Client Communication Conventions Manual (ICCCM) of 1988, defining PRIMARY and SECONDARY selections for immediate, mouse-driven text exchange (e.g., middle-click paste) alongside the CLIPBOARD for explicit copy-paste operations, influencing Unix-like GUIs.[28] The 2000s and 2010s brought globalization and web integration. Unicode support, via the CF_UNICODETEXT format, was introduced in Windows NT 4.0 in 1996 and expanded in Windows 2000 for full UTF-16 handling, enabling multilingual text transfer without character loss.[26] Integration with web technologies advanced with the CF_HTML format in 1999, accompanying Internet Explorer 5.0, which stored HTML fragments with context for formatted web content pasting into applications like Word.[29] These developments standardized the clipboard as a versatile, format-agnostic intermediary in modern GUIs.Technical Mechanisms
Data Formats and Storage
The clipboard stores data in a variety of formats to accommodate different types of content, enabling interoperability across applications. Common formats include plain text encoded in UTF-8 or Unicode, which serves as a universal fallback for textual data.[26][30] Rich text formats such as Rich Text Format (RTF) and HTML allow for styled content, including fonts, colors, and hyperlinks, while binary formats support images in standards like PNG or BMP and file references.[26][31] Serialized objects, often in JSON or application-specific structures, enable complex data transfer for modern apps.[30] Data is typically held in an in-RAM buffer managed by the operating system's kernel or dedicated services, such as a pasteboard server in macOS or global memory handles in Windows.[32][33] This memory-based approach ensures low-latency access but imposes practical size limits dictated by available system resources, with no predefined maximum in many implementations.[34][35] In X11-based systems, storage is often lazy, meaning data resides with the owning application until requested, rather than a centralized buffer.[36] Applications register multiple formats when placing data on the clipboard, prioritizing the most descriptive ones first, such as HTML over plain text.[26] During paste operations, the receiving application queries available formats and selects the best match through negotiation, falling back to simpler alternatives like plain text if richer formats are unavailable.[26][30] This mechanism promotes compatibility without requiring exact format matches. Clipboard data is inherently volatile, residing only in memory and cleared upon system reboot, application crashes, or new copy operations, with basic implementations avoiding any disk persistence to maintain security and performance.[32][36] This transience ties into broader access controls, where ownership changes trigger notifications to prevent unauthorized reads.Access and Security Models
Applications access clipboard contents through platform-specific APIs that provide functions for reading and writing data. In Windows, the Clipboard API enables synchronous access via functions such asOpenClipboard to claim ownership of the clipboard and GetClipboardData to retrieve data in specified formats after opening.[37] On Unix-like systems using X11, access relies on the selection protocol, where applications use Xlib functions like XSetSelectionOwner to claim the CLIPBOARD selection atom and XConvertSelection to request data from the current owner, supporting asynchronous transfers for large payloads via the INCR mechanism. These methods typically involve synchronous reads for immediate data retrieval, though asynchronous patterns emerge in protocols like X11 to handle delayed ownership responses.
The ownership model for clipboards in systems like Windows and macOS employs a single global buffer following a last-write-wins policy, where the most recent application to write data becomes the owner, overwriting prior contents without merging or versioning (with variations such as lazy storage in X11).[32] To inform applications of changes, systems broadcast notifications; for instance, Windows sends the WM_CLIPBOARDUPDATE message to registered windows via AddClipboardFormatListener whenever clipboard contents are modified.[38] This model ensures a unified, system-wide clipboard but introduces risks of data loss from concurrent writes, as no inherent conflict resolution exists beyond the timestamp of the last operation.
Security features in modern operating systems incorporate sandboxing to restrict unauthorized clipboard access, limiting inter-application data leakage. In iOS, the general UIPasteboard is system-wide and accessible by any app without explicit permissions; sandboxing confines apps to their own containers, limiting file system access, though network transmission of data remains possible, and the system notifies users when an app accesses pasteboard data without established user intent.[39] Similarly, Android's clipboard framework allows access via ClipboardManager without runtime permissions, but Android 10+ restricts background apps from reading the clipboard, enforcing foreground-only operations to mitigate stealthy surveillance.[40] In enterprise environments, data loss prevention (DLP) tools monitor clipboard activity for sensitive information, applying policies to block or redact transfers rather than native encryption, as standard OS clipboards do not encrypt contents to avoid performance overhead.[41]
Isolation techniques further enhance security by segmenting clipboard access, particularly to counter malware. Browsers implement per-site or per-session isolation through permission prompts; for example, Chrome requires user approval for JavaScript clipboard reads via the Clipboard API, confining access to secure contexts and user gestures to prevent automated hijacking. In X11-based systems, multiple selection atoms (e.g., PRIMARY for mouse selections, CLIPBOARD for explicit copies) act as virtual clipboards, allowing isolated buffers per interaction type without a single global store.[42] Enterprise solutions may deploy per-session virtual clipboards in virtualized environments, ensuring malware in one application cannot tamper with system-wide data by enforcing ownership checks and sandbox boundaries.[43] During access, these models interact with supported data formats to validate and convert contents, as detailed in storage mechanisms.
Platform-Specific Implementations
Windows
The Windows clipboard is implemented through the Win32 API, a set of functions and messages that enable applications to transfer data via cut, copy, and paste operations, with all applications sharing access to facilitate interoperability.[44] Core functions includeEmptyClipboard, which clears the clipboard and assigns ownership to the calling window, and SetClipboardData, which places data in a specified format onto the clipboard after opening it with OpenClipboard.[45] These APIs support standard formats such as CF_TEXT for ANSI text, CF_BITMAP for bitmap images, and CF_HDROP for file lists, allowing seamless handling of text, graphics, and files across applications.[4]
A distinctive feature of the Windows clipboard is its support for delayed rendering, where an application can place a promise of data on the clipboard by passing NULL to SetClipboardData without immediately providing the content; the system then sends a WM_RENDERFORMAT message to the owning window only when the data is requested during a paste operation, optimizing performance by avoiding unnecessary rendering.[32] Additionally, the clipboard accommodates multiple formats for a single item, enabling an application to offer the same data in various representations (e.g., text and bitmap) so the pasting application can select the most suitable one, with the owner responsible for rendering all promised formats upon receiving WM_RENDERALLFORMATS before losing ownership.[1]
Evolutions across Windows versions have enhanced clipboard functionality; for instance, Windows 95 introduced synergy with drag-and-drop operations through shell clipboard formats like CF_HDROP, allowing file transfers to leverage clipboard mechanisms for intuitive user interactions.[46] In Windows 10 and 11, the introduction of cloud clipboard integration via a Microsoft account enables syncing of clipboard history across devices, supporting up to 25 items including text and images, accessible through the built-in history feature toggled in Settings > System > Clipboard.[6]
The clipboard integrates with Universal Windows Platform (UWP) apps via the Windows.ApplicationModel.DataTransfer namespace, where developers use DataPackage objects to package content for Clipboard.SetContent during copy operations and Clipboard.GetContent for asynchronous retrieval during paste, ensuring compatibility with Win32 apps while respecting sandboxing.[47] For enhanced history management, Microsoft PowerToys provides the Advanced Paste utility, which extends the native clipboard history by allowing users to paste content in customized formats like Markdown or JSON and extract text from images via local OCR, activated via a configurable shortcut such as Win+Shift+V.[48]