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These present even more of a preservation problem than printed materials. Printed ephemera gave way to audio and video ephemera in the twentieth century. Even if radio and television stations preserve archives of their broadcasts, those backcatalogs are inaccessible in practice to the general public, leaving it to a small number of underground tape traders to exchange the rare, lucky moments when something unexpected or historical came across the air.Īn article on the Ephemera Society of America website notes Early TV broadcasts were not preserved (indeed, the technology to preserve them postdates the invention of television). Surprisingly, the great bulk of video and audio expression has, until recently, been ephemeral. Video and audio ephemeraīy extension, Video Ephemera and Audio Ephemera refer to transitory audiovisual matter not intended to be retained or preserved.

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Three hundred plus images of historic American ephemera predating 1960 are posted at This site adds 4 additional examples weekly.

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Over 2000 images from the John Johnson Collection are available to search online for free at VADS and more than 65,000 items are available online.

ANTONYM OF EPHEMERAL ARCHIVE

A particularly large and important example of such an archive is the John Johnson Collection of Printed Ephemera at the Bodleian Library, Oxford. Large academic and national libraries and museums may collect, organize, and preserve ephemera as history. This classification excludes simple letters and photographs with no printing on them, which are considered manuscripts or typescripts. In library and information science, the term ephemera also describes the class of published single-sheet or single page documents which are meant to be thrown away after one use. You can help Wikipedia by expanding it.Įphemera (ἐφήμερα) is a noun, the plural neuter of ephemeron and ephemeros, Greek and New Latin for ἐπί - epi 'on, for' and ἡμέρα - hemera 'day' with the ancient sense extending to the mayfly and other short lived insects and flowers and for something which lasts a day or a short period of time.

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Ephemerons: a new finalization mechanism, Google search for pdf.Today ephemerons are available in most Smalltalk dialects as well as many other languages with automatic garbage collection. They were used as the finalization mechanism in Visual Smalltalk Enterprise.

HistoryĮphemerons were first invented by George Bosworth while he worked at Digitalk. Therefore, the contents of an ephemeron can become eligible for garbage collection if and only if the key is garbage collectable which is the exact behavior which we would observe for an instance variable of the object. From then on, the contents of the ephemeron will be held weakly. While this problem can always be solved in any given concrete situation by using one of the various weak association types, choosing the 'right' kind of association depends on a variety of factors some of which can change dynamically.Įphemerons solve this problem by defining that the 'contents' (value) of an ephemeron will be held strongly until the key is known to be garbage collected.

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Here, the registry (a third party) will hold onto the association itself which would require manual removal from the registry (instead of automated garbage collection). Property - registry - association - object However, this is complicated by having an external association between the object and its property such as: When some property should be attached to an object, the property should (in terms of GC behavior) typically have the life-time that an instance variable of this object would have. Ephemerons solve a problem which is commonly found when trying to 'attach' properties to objects by using a registry. DescriptionĪn ephemeron is an object which refers strongly to its contents as long as the ephemeron's key is not garbage collected, and weakly from then on. Ephemerons are similar to weak pairs, but an object in an ephemeron's key field may be classed as 'almost collectable' even if it is reachable from the ephemeron's value fields. To make finalization more useful, 'almost collectable' is defined in terms of a new class of objects, called ephemerons. In computer science, finalization occurs when a garbage collector (GC) informs an application that an object is 'almost collectable.' It is used to help an application maintain its invariants. (November 2009)įor other uses, see Ephemera (disambiguation). Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article does not cite any references or sources.

Antonym of ephemeral