|
|
Posted by Gordon Burditt on 06/27/07 01:01
>>If you'd like to elaborate, I be interested in why you have the
>>requirement that time be monotonically increasing.
>
>Talk to the friendly government banking oversight agencies. It _may_
>be part of Sarbanes-Oxley Act of 2002 (Public Law 107-204), but the
>idea is the trustworthiness of the data. It's that old "what did
>they know, and when did they know it" problem. (I was hoping that
>Professor Mills included something about the reasoning in the RFCs,
>but a quick scan doesn't turn up an obvious reference.) The main
>point is that there are some situations where _changing_ the clock
>setting is a Class 1 felony. To keep the system in time, you are
>allowed to _drift_ the clock, but as in the world, time never goes
>backwards, nor stand still.
Ok, consider this situation: your bank clock is off. *BADLY*.
I'll let you decide whether that means it's off by several hours
or by several DECADES. In either direction. How did it get that
way? Perhaps some hackers breaking in to a backbone provider pulled
off a man-in-the-middle attack between you and the US Naval
Observatory, then forced you to reboot your systems with a power
outage, since your UPS depends on that last batch of sabotaged
batteries. Perhaps it was a virus. Perhaps it was a bribed employee,
or just a scared one with guns pointed at his family. Or maybe it
was just a bad bit in a failed clock chip.
It is also my observation that your system clock, running with NTP,
can get quite a bit off after a several-day loss of network
connectivity followed by it coming back up. NTP does correct for
some of the error. Then again, the clock error depends on temperature
by quite a lot.
Now, WHAT DO YOU DO ABOUT IT? Set the clock, or let it drift into
correctness a couple of decades after your prison sentence is up?
>>In the real world, things happen,
>
>And when thing happen, you document the crap out of it, and then figure
>out how to prevent that crap in the future. while you also hope that
>the Feds (perhaps the SEC) will buy your story.
>
>>and no software is perfect or bug-free.
>
>Cue the joke about an update to correct an error invariably ADDs more
>bugs.
>
> Old guy
Navigation:
[Reply to this message]
|