Archived posting to the Leica Users Group, 2015/10/20

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Subject: [Leica] Babbage Difference Engine
From: kanner at acm.org (Herbert Kanner)
Date: Tue, 20 Oct 2015 14:55:26 -0700
References: <8D2D9843A07B636-2730-AD1E4@webmail-vd012.sysops.aol.com>

Herbert Kanner
kanner at acm.org

Question Authority and the authorities will question you.

> On Oct 20, 2015, at 12:25 PM, Larry Zeitlin via LUG <lug at 
> leica-users.org> wrote:
> 
> Herbert,From Wikipedia?s article on magnetic core memories:
> "Two key inventions led to the development of magnetic core memory in 
> 1951. The first, An Wang's, was the write-after-read cycle, which solved 
> the problem of how to use a storage medium in which the act of reading 
> erased the data read enabling the construction of a serial, 
> one-dimensional shift register of o(50) bits, using two cores to store a 
> bit. A Wang core shift register is in the Revolution exhibit at the 
> Computer History Museum. The second, Jay Forrester's, was the 
> coincident-current system, which enabled a small number of wires to 
> control a large number of cores enabling 3D memory arrays of several 
> million bits e.g. 8K x 8K x 64 bits.?  So I guess we are both right.
> 
> 
> Now back to the Leica S. A toy for the very rich.
> 
> 
> Larry Z
> 
> 
> _______________________________________________
> Leica Users Group.
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> 



In reply to: Message from lrzeitlin at aol.com (lrzeitlin at aol.com) ([Leica] Babbage Difference Engine)