- Had an interview
- Posted by Andrew Smallshaw on May 7th, 2008
On 2008-05-06, Tom <tom@nospam.com> wrote:
That is an external input in my book. Maybe not external to the
system but certainly to the software. As such it comes within the
requirements for idiot-proofing. My original post was primarily
concerned with not constantly checking _internally_ generated
values, at least not in an program not in debug trim.
As for what action to take in the eventuality you decribe it isn't
perfectly clear cut. If it is perfectly clear (to the code) that
it is in fact a sensor failiure then disabling that ring is indeed
a sensible option. However, this depends on the sensor failing in
a consistent and predetermined fashion, that manner being known by
the SW people, and the system actually havign the capability to
robustly diagnose the failiure from within.
If the cooker is in an 'unknown' state then 1) is the best option.
You can live without a cooker after all. Sure it may be inconvenient
but you will get by. The situation is no different to that
experienced in a power cut after all.
For a start it has to be clear (to the code) that it
is in fact a sensor failiure for disabling that hob to be the
obvious option. If the cooker is in an 'unknown' state 1) would
be the best bet.
Does anyone remember when you used to turn on your TV and it just
came on? Well, the audio came on straight away and it took a few
seconds for the screen to warm up. Changing channels was always
instantaneous. Now it takes maybe ten seconds for the picture to
appear, another couple of seconds for the audio to commence and
what seems like three weeks for the onscreen display to disappear
so you can see what you are watching.
Only for the OSD to reappear (taking up literally half the screen)
advising you of a slightly dodgy signal that you would have been
completely oblivious to in terms of picture quality unless you had
been advised of it. Then you have the curse of set top boxes - I
have one in particular that ties itself up in knots that can only
be resolved by power cycling at least once a week.
--
Andrew Smallshaw
andrews@sdf.lonestar.org
- Posted by Dombo on May 8th, 2008
Tom schreef:
Many devices have an automatic reset button, better known as 'watchdog
timer'.
- Posted by Everett M. Greene on May 9th, 2008
Robert Adsett <sub2@aeolusdevelopment.com> writes:
I'm coming into this discussion late but I'm amazed
nobody suggested x ^= 3. If you want to ensure some
meaningful output with out of range input then
x = (x ^3) & 3 or x = (x & 3) ^ 3. Of course, none
of these solutions works if x is 0 or 3 intially.
- Posted by Spehro Pefhany on May 9th, 2008
On Fri, 9 May 2008 10:25:55 PST, mojaveg@mojaveg.lsan.mdsg-pacwest.com
(Everett M. Greene) wrote:
Who you callin' a nobody, and why are you amazed?
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
