[news_to_me]

A progress bar should not indicate progress over multiple tasks — a segmented progress bar is better, or a series of spinners, or just a single spinner for the whole set. A progress bar should measure exactly one metric, where the total is known.

[dkersten]

It reminds me of the old (maybe it still does it, I dunno) windows install progress bars vs ones where multiple things are wrapped into one.

With multiple things wrapped into one, you often end up in situations where 0-99% (or whatever) might happen super fast but that last 1% takes ages, making the progress bar useless as a "something's happening" indicator.

Those old windows installers used two bars: the top one was basically a steps indicator (file N of M, for example) -- just like the single bar for multiple tasks. But the second bar was a per-file bar. So if step 99 took longer, you had a second bar showing you that steps/files progress.

[WorldMaker]

I played with the idea of using a singular circular progress bar for composite progress notification. The basic idea was that if you keep the tail chasing the head, and the head always moving clockwise, the progress bar never gives the impression that it "shrinks backwards", it is always forward motion, but in the worst case when the tail catches up with the head (you discover more sub-tasks) it basically becomes a spinner until the tail starts to lag the head again. Tuning the animation parameters for that provided a lot of options to get a good feeling progress bar that reported a heterogeneous source of various tasks, some of which discovered/added while in progress of the overall whole.

My demo has unfortunately fallen to web bit rot and needs to be updated, but the code is here to explore: https://github.com/worldmaker/compradprog

[news_to_me]

Yeah, I think I remember those! If it were me, I would turn the segmented bar into a checklist, since you can add a description and I think it looks nicer. But the approach was a good one imo.

[dkersten]

Sure, that top bar is a "steps completed" bar, so something other than a normal progress bar may be better. A checklist would work, unless space confined. Depends on the number of items. Maybe a segmented bar where it fills one segment for each item. If there are a lot of items, though, just an "X/Y steps completed" may work best: its simple and easy to understand.

[magicalhippo]

Back in Windows 3.11 days, I noticed a patter with installers. Their progress bar would go steadily up for quite a while, and then suddenly spend 3x as long on just one or two percentage points.

It didn't take me long to realize that the progress bar measured bytes written to disk, but when it was seemingly "stuck", it was creating a lot of small files.

Instead of bytes written, what I really cared about is "how done are you?" and that would have been better represented by a function of both number of files created _and_ bytes written. I don't think the weighting of those two had to be very accurate to be a big improvement.

[wolrah]

Exactly! The biggest problem with most progress bars is that they tie together multiple unrelated things that aren't even measured in the same way to a single indicator.

If there are multiple independent tasks, give me multiple independent indicators of their state. Multiple instances of the same class of task can of course be grouped, you don't need to list every file copy independently, but a file copy and an external dependency installer shouldn't be two stops on the same progress bar.