Here is why progress bars are not loading evenly on your computer


Why does this thing never run at a constant speed when there is a progress bar on your computer? Why does all the little one stop and start?

This is the question that YouTuber Tom Scott is addressing for his latest video, which breaks down the many complexities of creating a progress bar that actually works smoothly.

“An installer may need to download files from the Internet, decompress these files, save these files along with reading or deleting existing content, and may also need to make some changes to system settings,” explains Scott. “In theory, a programmer could figure out roughly how long each of these processes will take and then manipulate the progress bar accordingly, but each of these steps will take different amounts of time on different machines.”

Downloading, Scott explains, depends on the speed of the internet, while decompression is affected by the computer’s processor and file storage / reading is affected by the speed of the disk. Even running a progress bar based on the MB of data transferred can go wrong, as copying many small files can take longer than some large ones.

What if you take all of that into account and try to figure everything out so that the bar runs smoothly?

“That could still go wrong,” says Scott. “Because of the speed of your broadcast, download, or complicated video rendering, all of these speeds can change at any time, depending on what the device is doing or what the user is doing.”

At the end of the day, Scott argues, it might not matter that much.

“I think progress bars should just be a little jagged because they reflect something that is really happening,” he concludes. “Also, the most important job of a progress bar is not to give an accurate and accurate estimate of the time remaining. It’s great when you can, but the most important job is to reassure the user that yes, things will happen. Progress will be made made. “