Re: "Distributed" vs "Decentralized systems"

From: Andrew Gabb (agabb_at_tpgi.com.au)
Date: 09/18/04 

Date: Sat, 18 Sep 2004 23:56:18 +0930

I think of a distributed system as one where the functionality
*depends* on more than one node performing, ie there is no
single/central node/server which provides the functionality. To me
this implies *spread* of functionality.

A decentralised system (I'd say) is one where the performance does
not depend on a single/central node/server. Multiple regional
mirrors might be used to achieve this, but it is not necessarily
'distributed'.

The difference is subtle and the terms are probably used more or
less interchangeably by many.

Andrew

Lew Pitcher wrote:

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> dd wrote:
>
>>What is the difference between distributed and decentralized systems?
>
>
> As I understand it, a distributed system consists of a single component
> that provides a service, and one or more external system that access the
> service. Think of this as a hub and spoke design, where the hub is the
> central service and the endpoints of the spokes are the external systems.
>
> OTOH, a decentralized system consists of many external systems that talk
> to each other. Think of this as a fishing net design, where each knot
> represents an independant system, and the lines between the knots
> represent the communications channels between systems.
>
> The difference is that with a distributed system (as above), if you
> break the hub, you break the system. OTOH, if you break one of the
> systems in a decentralized system, you've only lost one element, and not
> the whole system.
>
> - --
>
> Lew Pitcher, IT Consultant, Enterprise Application Architecture
> Enterprise Technology Solutions, TD Bank Financial Group
>
> (Opinions expressed here are my own, not my employer's)
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-- 
Andrew Gabb
email: agabb@tpgi.com.au       Adelaide, South Australia
phone: +61 8 8342-1021, fax: +61 8 8269-3280
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