Re: [stellation-res] Timing: The Solution

[Dave Shields <shields@xxxxxxxxxxxxxx>]

On Sun, Sep 15, 2002 at 11:10:50AM -0400, Jonathan Gossage wrote:
> 
> 
> There is a method that will deal with this scenario as well as the previous
> one. If you force all files written to the workspace to have timestamps 2
> seconds earlier than the current time then I think you will avoid the
> scenarios presented above.

I am wary of forcing the timestamps to be wrong. Also, why just two seconds?
> 
> However there is another scenario that is a real killer. Consider a PC with
> a system clock that drifts forward in time one second per hour. Consider
> also that this system updates its time each hour from a time server. The
> result will be that once an hour approximately the local clock will be set
> back by one second. This gap presents an opportunity for an update
> immediately following a checkin to get a back-dated time stamp that can
> cause the update to be missed.
> 
> I have only presented two scenarios here, but I believe thatthere are other
> possible ones. While the window of opportunity for failure is quite small,
> it is real and if we want to deliver a robust product I do not think that we
> should rely on a mechanism which is out of our control and which can lead to
> missed checkins
> 
I agree there is problem, but it's hard to see how we can anticipate all scenarios.

dave

PS: I have filed bug report to IBM's Java center re returning bogus values from
java.io.File.lastModified(), after checking that the latest version had the
same bug I found in an earlier version.

-- 
Dave Shields, IBM Research, shields@xxxxxxxxxxxxxx.