Write-only memory (joke)

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,^[1][2] a staple of software engineering lexicons,^[3] and included in collections of the best hoaxes.

Signetics

The datasheet was created "as a lark"^[4] by Signetics engineer John G ‘Jack’ Curtis^[5] and was inspired by a fictitious and humorous vacuum tube datasheet^[6] from the 1940s. It was seen as "an icebreaker" and was deliberately included in the Signetics catalog.^[5]

Roy L Twitty, a Signetics PR person, released a tongue-in-cheek press release touting the WOM on April 1, 1973.^[7]

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 V_ff (vacuum tube filament) supply, a +10 V_cc (double the V_cc of standard TTL logic of the day), and V_dd of zero volts (i.e. ground), ±2%. It was specified to run between 0 and −70°C.^[8]

Apple

In 1982, Apple published their official Apple IIe Reference Manual (part number A2L2005),^[9] which included two references to write-only memory.

On page 250:

• write-only memory: A form of computer memory into which information can be stored but never, ever retrieved, developed under government contract in 1975 by Professor Homberg T. Farnsfarfle. Farnsfarfle's original prototype, approximately one inch on each side, has so far been used to store more than 100 trillion words of surplus federal information. Farnsfarfle's critics have denounced his project as a six-million-dollar boondoggle, but his defenders point out that this excess information would have cost more than 250 billion dollars to store in conventional media.

On page 233:

• bit bucket: The final resting place of all information; see write-only memory.

Book

In 1995 Computer Contradictionary book, it reports EWOM, or Erasable Write-Only Memory (an analogy of EPROM), a memory copyrighted by IBM (Irish Business Machines), which allows the data to be written into and then erased from, for memory re-use.^[10]

With the explosive growth of the amount of video data available both online and in private use, there emerged a common joke that video tapes and other video media are "write only memory", because without efficient means of search and retrieval for video data archives very little is viewed after recording.^[11][12]

See also

• Write-only memory (engineering)
• Write-only language
• /dev/null
• Bit bucket, in computers, a destination to write data which does not retain it
• FINO — First In, Never Out scheduling algorithm
• Turboencabulator

References

1. Pease, Robert A. "The origin of the WOM – the "Write Only Memory"". National Semiconductor. Archived from the original on 26 September 2012. Retrieved 2011-11-28..
2. "Are you fooled?". China Daily. 2011-04-02. Retrieved 2011-11-28.
3. Raymond, Eric S (ed.). "write-only memory". The Jargon File. CatB. Archived from the original on 24 November 2006. Retrieved 2011-11-28.
4. Sigwom.
5. Sigwom.
6. 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.
7. Tina (ed.), "The original papers on the invention of the best electro…", Funny pages
8. Curtis, John G ‘Jack’ (1972). "Signetics 25120 Fully Encoded, 9046xN, Random Access Write-Only-Memory" (PDF) (photocopy). Signetics. Archived from the original (PDF) on March 16, 2012. Retrieved 2012-03-16..
9. Apple IIe Reference Manual, Apple Computer, 1982, part number A2L2005, 266 pp.
10. EWOM (Google books), p. 69.
11. Advances in Visual Information Systems: 4th International Conference, VISUAL... (Google books), p. 49.
12. Blitzer, Herbert L; Jacobia, Jack, Forensic Digital Imaging and Photography (Google books), p. 61.