In Windows, when I access a folder's properties in order to asses how large it is, I have to wait while it sums up its size, and I can watch its size in MB grow while doing so. This process can take up long amounts of time.
However, when I check my disk properties (ie C:), the filesize is instantly displayed with no delay.
Why does this happen?
BTW, I'm on an SSD with read times well over 2GB/s so that shouldn't be the issue.
When you look at the properties of a folder, it needs to iterate through all the sub-folders and files, reading the properties (name, size, etc) of everything. That requires a lot of calls to read data from the disk.
When you look at the properties of the disk, it simply needs to look at the bitmap over free/used space and calculate how much there is of each.
Note that this a quite simplified explanation, and it depends on the file system used how the data is stored.
