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From: Paul Koning <pkoning_at_equallogic.com>

Date: Wed Sep 29 08:17:58 2004

*>>>>> "Pete" == Pete Turnbull <pete_at_dunnington.u-net.com> writes:
*

Pete> As for confusing addition and the logical OR function with

Pete> binary numbers, you don't normally perform logic on binary

Pete> numbers, only on bits representing truth values. Describing

Pete> "1011 OR 0101" as part of a logic equation is sloppy; it's

Pete> actually four put together.

*>From a math point of view, justifying the use of add and multiply
*

symbols, this is viewed as arithmetic modulo 2. You'll note that

addition mod 2 is exactly XOR (not inclusive OR) and multiplication is

exactly AND -- which is why that notation came across.

Looking at things this way is helpful if you want to understand CRC,

for example. Or so I've heard -- number theory is unfortunately

mostly over my head. Same goes for coding in general (ECC and such)

or various forms of encryption.

paul

Received on Wed Sep 29 2004 - 08:17:58 BST

Date: Wed Sep 29 08:17:58 2004

Pete> As for confusing addition and the logical OR function with

Pete> binary numbers, you don't normally perform logic on binary

Pete> numbers, only on bits representing truth values. Describing

Pete> "1011 OR 0101" as part of a logic equation is sloppy; it's

Pete> actually four put together.

symbols, this is viewed as arithmetic modulo 2. You'll note that

addition mod 2 is exactly XOR (not inclusive OR) and multiplication is

exactly AND -- which is why that notation came across.

Looking at things this way is helpful if you want to understand CRC,

for example. Or so I've heard -- number theory is unfortunately

mostly over my head. Same goes for coding in general (ECC and such)

or various forms of encryption.

paul

Received on Wed Sep 29 2004 - 08:17:58 BST

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