The obvious antonym to read-only
memory. Out of frustration with the long and seemingly useless
chain of approvals required of component specifications, during which no
actual checking seemed to occur, an engineer at Signetics once created a
specification for a write-only memory and included it with a bunch of other
specifications to be approved. This inclusion came to the attention of
Signetics management only when regular customers
started calling and asking for pricing information. Signetics published a
corrected edition of the data book and requested the return of the
‘erroneous’ ones. Later, in 1972, Signetics bought a
double-page spread in Electronics magazine's April
issue and used the spec as an April Fools' Day joke. Instead of the more
conventional characteristic curves, the 25120 fully encoded, 9046 x
N, Random Access, write-only-memory
data sheet included 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 supply, a +10V VCC, and VDD of 0V,
±2%.