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Write-only memory (WOM) is the opposite of read-only memory (ROM). By some definition, a WOM is a memory device which can be written but never read. Since there should be no practical use for a memory circuit from which data cannot be retrieved, the concept is most often used as a joke or a euphemism for a failed memory device. The first use of the term is generally attributed to Signetics in 1972. Signetics published some ''write-only memory'' literature as the result of an inside practical joke, which is frequently referenced within the electronics industry,〔.〕〔 〕 a staple of software engineering lexicons, and included in collections of the best hoaxes. ==Signetics== The datasheet was created "as a lark"〔.〕 by Signetics engineer John G ‘Jack’ Curtis〔.〕 and was inspired by a fictitious and humorous vacuum tube datasheet〔''Wemac 1Z2Z Slightly Tentative Data'', Eitel-McCullough, Inc. 1953, itself a successor to ''Umac 606 Infernal Anode Phantasatron Data Sheet'', Eitel-McCullough, Inc., 1950, both referenced on ("Wemac 1Z2Z Data Sheet", sigwom.com ). Note the reference to 'encabulitzation' in the 1Z2Z data sheet.〕 from the 1940s. It was seen as "an icebreaker" and was deliberately included in the Signetics catalog.〔 Roy L Twitty, a Signetics PR person, released a tongue-in-cheek press release touting the WOM on April 1, 1973. Instead of the more conventional characteristic curves, the 25120 "fully encoded, 9046×N, Random Access, write-only-memory" data sheet included meaningless diagrams of "bit capacity vs. Temp.", "Iff vs. Vff", "Number of pins remaining vs. number of socket insertions", and "AQL vs. selling price". The 25120 required a 6.3 VAC Vff (vacuum tube filament) supply, a +10 Vcc (double the Vcc of standard TTL logic of the day), and Vdd of zero volts (i.e. ground), ±2%. It was specified to run between 0 and −70°C.〔.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Write-only memory (joke)」の詳細全文を読む スポンサード リンク
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