On Mar 4, 9:31*pm, wrote:
On Thu, 4 Mar 2010 05:17:57 -0800 (PST), wrote:
On Mar 4, 12:35*am, wrote:
On Wed, 3 Mar 2010 11:03:39 -0700, "chaniarts"
wrote:
wrote:
On Mar 2, 9:01 pm, (Doug Miller) wrote:
In article ,
(Don Klipstein) wrote:
In , Doug Miller wrote:
The thing that really stood out to me was the statement by Toyota's
president that they're going to look into programming a brake
override for the throttle.
I have only one question: WHY IN GOD'S NAME WAS THAT NOT THERE
FROM THE BEGINNING?
*Programming* a throttle override by the brake? As in relying on
lack of electronic malfunction in order to have the brake reliably
apply an override onto the throttle?
Since the override becomes necessary only in the event of a throttle
malfunction, for the override to not work would require a second
malfunction.
Clearly two simultaneous malfunctions are *far* less likely than any
single
malfunction.
That's obviously totally false. *Let's say I have a single computer
that is running the throttle, the shift interlock, and the engine shut
off via the start/stop button. *Actually that doesn't sound that far
fetched. * Clearly you could write a program in such a way that the
program under certain conditions goes into a program loop where it
will no longer respond to either a change in throttle input or the
stop button and will also not unlock the shift. * That's a single
program failure, not two simultaneous malfunctions.
but most modern cars have probably 30, and some upwards of 100, different
computers.
Nope - unless you count all the CanBuss controll modules - and even
then 30 would be stretching it.- Hide quoted text -
- Show quoted text -
Nonsense. * A computer in any reasonable context means a CPU of some
kind executing a program defined by software. * There most certainly
are many computers in a car today. * Aside from the ECU, there
typically are CPU's for things like the ABS brakes, climate control,
radio, GPS, air bag, etc. * Some or all of those computers may be
linked together, some may issue commands to others, etc, but that
doesn't mean there are a lot more than 1.
Well, I happen to know that the engine and transmission controls are
"one computer" . The climate control, air bags, *radio, compass, etc
are another "computer".
I'd love to see a reference that says all that stuff, including the
air bags, are run by one computer on any car. You also seem to be
making very broad generalizations as to how all cars are designed.
A simple google search on "air bag computer" brings up lots of hits.
There is discussion on where it is, how to repIace it, etc. Funny
how they call it an airbag computer, not an airbag/radio/compass
computer and there is no mention of it doing anything other than
control the airbags. Here's one link with a picture of the airbag
computer from a Nissan.
http://forums.nicoclub.com/zerothread/351612
And I can think of some very good reasons why designers would want an
airbag computer to be dedicated to that one specific task. Can you?