Re: Everything is for the Best in this Best of All Possible Worlds
This has nothing to do with disk performance of different computers.
This is about the differing performance of disk stores vs memory stores on the same computer, whether lightning fast SLC SSD or a 5400rpm slow laptop HDD. The speed of even the fastest SSD available pales in comparison to memory, it is an order of magnitude or more difference, with spinning rust being a further 1 or 2 orders further back.
To avoid leaving 'fingerprints' on the computer, a browser in incognito/private mode will not write to disk, it will use a memory store instead (similar to a ramdisk). A browser not in incognito will write to disk. A smart website, using javascripts, can detect that performance difference irrespective of the actual type of disk (fast SSD, Optane, slow HDD) being used. Therefore the website will know that incognito/private is being used, and tell you to f-off, you aren't allowed to use the site at all.
At least, that is the consequence of Chrome's fix.
However, without the fix it is even easier to detect incognito mode and refuse service. Prior to this fix, the browser simply did not allow any file access at all. So the website (again via javascript) will attempt to read/write a file, and get a "not allowed" error back, therefore it now knows incognito is being used.
Therefore this issue already exists in multiple browsers from multiple vendors (i.e. Chrome, Firefox, probably others). Chrome has attempted to fix it with this fix, but this article is pointing out that this doesn't fix the existing issue. Or rather, it fixes the existing mechanism used to detect incognito, but introduces a new mechanism that is a little harder to use to detect incognito.