Time remaining counter

Can anyone tell me how the 'time remaining' counter while copying files in Windows works?
That counter goes up and down, especially when the filesize differs greatly. That I can understand, each file has overhead and a lot of small files up the copy time.
What I'd like to know is what the counter is exactly based on: the last copied files, data transferred in the last, say, 10 seconds, or maybe the last 10 files.

Greater Monster wrote:

Can anyone tell me how the 'time remaining' counter while copying files in Windows works?
That counter goes up and down, especially when the filesize differs greatly. That I can understand, each file has overhead and a lot of small files up the copy time.
What I'd like to know is what the counter is exactly based on: the last copied files, data transferred in the last, say, 10 seconds, or maybe the last 10 files.

I can understand why it is impossible to give a exact time. Besides file sizes ect (which can be seen in advance) you also have a load of other factors the change during copying. If you copy and during the copy you start a program, there goes your estimate. Strictly speaking a change in outside temperature can influence the computers speed and thus the copy-speed.

But somewhere someone decided that, although it would be an estimate, some calculation will be made.
And what that calculation is, that is what I'd love to know.

I think it is based on the copy-speed of the last completed file, based on the behavior of the estimate. But I am only halfway sure.

Judging by how often it updates, it's either by the last  second's speed or by how long it took the last 100k (or so) to copy. I'm guessing the former. I'd like someone "in the know" to clear this up, though, as my curiousity has now been spiked.

I think your theory is better because the time can change during the copying of a file (as opposed the right or shortly after it). You see that even better when copying a single large file of the internet (assuming that uses that same calculation).

A website filled with Microsoft developers, please answer, please

Yesterday I was at the Microsoft Technet/MSDN sessions in Rotterdam (The Netherlands) talking on this subject with two Dutch Microsoft developers and although they offered a few possibilities, they didn't have the answer anymore than non-Microsoft developers.
Well, I give up (no, I don't, knowing myself). What caculation is used? Moving average? Data left to copy divided by the speed at that moment?
Will I ever find the programmer that developed that routine. Stay tuned