[E-voting] details about ClearVoting

Casey, Dermot (GE Money) Dermot.Casey at ge.com
Mon Sep 3 10:24:48 IST 2007


Tim

I think this quote from Wikipedia sums it up (below). Fundamentally when
flying even with multiple systems there is still a level of risk
involved (see Computer Related Risks and other sources on this). In
addition all the information on aircraft problems (disasters and near
misses) is public and publically investigated. So its possible to have a
reasonable degree of confidence in the systems. On the whole I can't
trust any single computer system. And this was underlined to me when I
saw an ATM machine transaction fail and the proper rollbacks didn't work
!

Regards

Dermot

[from http://en.wikipedia.org/wiki/Fly-by-wire#Fly-by-wire ]

"Nonetheless the top concern for computerized, digital fly-by-wire
systems is reliability, even more than analog systems. This is because a
computer running software is the only control path between pilot and
control surfaces. If the computer software crashes, the pilot cannot
control the aircraft. Therefore virtually all fly-by-wire systems are
triply or quadruply redundant: they have three or four computers in
parallel, and three or four separate wires to each control surface. If
one or two computers crash, the others continue working. In addition
most early digital fly-by-wire aircraft also had an analog electric,
mechanical or hydraulic backup control system.

For airliners, redundancy improves safety, but fly-by-wire also improves
economy because the elimination of heavy mechanical items reduces
weight.

Boeing and Airbus differ in their FBW philosophies. In Airbus aircraft,
the computer always retains ultimate control and will not permit the
pilot to fly outside the normal flight envelope. In a Boeing 777, the
pilot can override the system, allowing the plane to be flown outside
this envelope in emergencies. The pattern started by Airbus A320 has
been continued with the Airbus family and the Boeing 777. The Boeing 787
makes some minor improvements in the control laws, adopting some
protections that Airbus has had in place for decades."




-----Original Message-----
From: e-voting-bounces at lists.stdlib.net
[mailto:e-voting-bounces at lists.stdlib.net] On Behalf Of Timothy Murphy
Sent: 31 August 2007 22:19
To: e-voting at lists.stdlib.net
Subject: Re: [E-voting] details about ClearVoting

On Thu 30 Aug 2007, Casey, Dermot (GE Money) wrote:


I can't ever trust a single computer system.


Don't you ever fly?



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