Destroying the memory of Gemini

Whilst reading a bit from ``Computers in Spaceflight: The NASA
Experience,'' by James E Tomayko, I came across the mtion that the
Gemini Digital Computer was ``the first use of core memory with a
nondestructive readout'' --
http://www.hq.nasa.gov/office/pao/Hi...ers/Ch1-5.html

A friend of mine who's done some work with core memory says that
just ain't so, that you couldn't read core memory nondestructively and
the best you could do is set up a mechanism to read-and-promptly-rewrite
the bit.

So ... has my friend missed a clever design for the reading of
memory, or has Tomayko (who was writing in the mid 1980s, and cites a
couple of contemporary references and interviews) misunderstood the
by-then-quite-obsolete design?

--
Joseph Nebus
------------------------------------------------------------------------------

(Joseph Nebus) writes:

Whilst reading a bit from ``Computers in Spaceflight: The NASA
Experience,'' by James E Tomayko, I came across the mtion that the
Gemini Digital Computer was ``the first use of core memory with a
nondestructive readout'' --
http://www.hq.nasa.gov/office/pao/Hi...ers/Ch1-5.html

A friend of mine who's done some work with core memory says
that just ain't so, that you couldn't read core memory
nondestructively and the best you could do is set up a mechanism to
read-and-promptly-rewrite the bit.

So ... has my friend missed a clever design for the reading of
memory, or has Tomayko (who was writing in the mid 1980s, and cites
a couple of contemporary references and interviews) misunderstood
the by-then-quite-obsolete design?

Your friend has missed the `two hole donut' aka core. Write to both
holes, read from one. Some of the core vintage texts mentioned it,
but not in any detail AIR. I never knew it had been used in anger
for a real design!

--
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West Australia 6076
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