Best laid plans
The testing missed some real world event. It happens and fixed in a day. Pretty good really, and it's not as if it was a plane.
Australia’s stock exchange took most of Monday off, without warning, after new software went live... and quickly created problems that made trading inadvisable. A statement [PDF] said a shutdown of the exchange was needed because: "A software issue limited to the trading of multiple securities in a single order (combination …
It may be as simple as no one informing the developers and the tester of the "recommended" way to pass orders in specific cases.
So it was never included in the unit tests and validation procedures.
Like the time some 30 years ago when I asked a colleague working with the Sealink (ferry across the Channel) how the billing system was handling the case of a user saying "Egg" (as in Easter Egg) at the counter when buying tickets for the Easter week-end.
Of course he was a little surprised by my question, and then I provided him with a copy of an advertisement published the day before (Thursday before Easter), informing potential customers that when saying "Egg" at the counter they would get a rebate.
My colleague immediately phoned his counterpart at Sealink to get more information, and discovered that nobody there was aware of this marketing coup...
I don't remember what was done, but remember it was Friday morning, with the rebate going live on the evening, and no Internet then to deliver any needed patch...
They seemed to do it all by the book.
Extensive testing, pulled it when it had issues, fixed in a day.
Done.
I've done major switchovers and they are never fun, there is always that random thing you can never plan for. We always had to fix on the fly though, but we weren't dealing with billions of dollars an hour.
Software problems happen all the time. But stock exchanges are expected to operate reliably ....
Yes, there's the sub-prime problem highlighted there immediately, .... operating reliably and operating logically are not the same, and computer software is not very good at doing anything illogically ?
You do realise stock markets are rigged and chock full of zombie operations, yes, and they keep a whole raft of chancers living the life of Riley at the expense of reality on the wealth of others????
That probably accounts for its addictive attraction ..... a lot of something for practically nothing.
Where have you been all this time, Aristotles slow and dimwitted horse, for since when recently has anything needed to make any sense?
Haven't you sussed that's the abiding expanding problem in these frenetic and fanatical 0day days which just keeps on giving more of the same old nonsense until it becomes so overwhelming and almighty self-destructive.
Interesting. Are you speaking with direct knowledge? Or are you someone not living the life of Riley, who is just jealous? ..... Anonymous Coward
Yes and No are correct possible answers there, AC, and therefore most probably honestly truthful too.
There should be no ambiguity resting there. Any doubts surfacing would be wholly in residence with your good self/selves.
Just remember that raft of chancers is ensuring you have a pension when you retire...... druck
Oh please ...... who on Earth told you that, and how well do you think it is presently going?
Many would say, and I might concur and concede that they are certainly trying to ensure they retire with a fabulous pension, and who wouldn't if they were able and/or enabled, eh? 'Tis surely a dream come true and much to be appreciated. Quite what happens to anyone else is way beyond their command and control and for them to think otherwise is probably delusional.
RUN.
IN.
PARALLEL.
WITH.
OLD.
SYSTEM.
DUPLICATING.
THE.
REAL.
LIVE.
DATA.
Anything else is not "testing", it's just guessing if it will work or not.
Branch off the real data (or even just a portion), feed it through your test system, check that the answers match and/or that the behaviour is as expected.
Leave it like that for a significant period of time. Only THEN do you think about actually swapping out the old.