Unix was originally designed to perform file system operations in memory, and to update the disk blocks only every 30 seconds during
sync. This resulted in a much faster user experience than MSDOS many years ago that accessed the disk blocks directly for each file system operation. But today using Windows 7 I still see that copying lots of small files takes much longer than copying one big file of the same size.
For example: a Visual Studio C# Asp web project Publish directory contains 2000 files, total 150 MB, zipped (7Zip) 90 MB.
- Copy the entire directory to the same disk: 30 seconds
- Zip: 5 seconds
- Copy one zipped file: 2 seconds
- Unzip: 65 seconds. (On another machine: 20 seconds)
Computationally, unzipping should go faster than zipping. So the unzipping might be dominated by the file system performance.
Disk fragmentation might be a factor, and the reason another similar machine might be faster in handling many file system operations. But if disk fragmentation is a factor here, it might indicate that the user has to wait for each file system operation to finish before the next one starts, i.e. like old DOS.