[wongarsu]

When I implement progress bars I most often implement "pessimistic progress", so "considering all timeouts, worst case we are 46.5% (of the time) to some result", with an update every few hundreed milliseconds. As possible mix in data from completed subtasks.

Nobody ever complains if the process suddenly speeds up because progress was made before the timeout, as long as your initial estimate wasn't absurd (looks at Windows Explorer). Even a naive progress bar counting down the 60s timeout is more informative and satisfying to watch than an endless spinner.

[delinka]

Absurd initial estimate? All of the estimates tend to be absurd.

Done in 30s ... I mean 15min ... ah, 10s ... 1hr 7min ...

Oh, come _on_ ...

[Nition]

Windows 95/98 used to occasionally do some particularly insane estimates. I took this screenshot many years ago of copying a tiny NetHack install between drives: https://i.imgur.com/q7tc9R1.png

[NeedMoreTea]

Vista, I think it was Vista, "fixed" that by adding an estimation pass first, that often took longer than the copy itself, and was almost as bad at estimating. It sometimes took much longer. The fix was far worse than the problem, yet it survived unchanged.

It was so bad I ended up discovering Teracopy which was decent at estimation, and far faster at copying. Was a must-have until I migrated away from Windows.

[bcaa7f3a8bbc]

How exactly do utilities like Teracopy implement high-performance copying? In other words, what are the performance bottlenecks in explorer.exe? Personally, I've observed that:

1. Explorer attempts to do a file enumeration prior to copying, which sometimes could waste a lot of time.

2. It seems tools like Teracopy use buffering aggressively, which can speed up the copying significantly based on my experience on Windows XP with slow HDDs.

Are there any other points worth noting?

[NeedMoreTea]

Single pass and aggressive buffering seems to cover what I remember, but it worked better than it I expected, even on high speed drives or SSD to high speed drive. They may have had other tricks, it's been a while now.

The other thing that I liked is it's non-blocking - you can continue doing copies while one is in progress, if it's to the same destination it gets added to the queue in progress. If different destination it goes in a new queue that waits for the first to finish.

[mkd1964]

We used to call these "Microsoft Minutes"...