One of the first reactions to your system acting slow is to defragment your hard disk. If you ask Windows users, they will tell you that they have done it for years (about once a month is recommend) so that’s what comes naturally.
Regarding Mac users wanting to defragment their hard disk but not being able to find it even after searching in the Disk Utility shouldn’t be concerned
- The file system looks for the largest free areas on the hard disk to allow large file to be located without being divided (fragmented)
- Small files will be collected into a group and will be moved to a larger area on the hard disk, the process of moving these files will defragment them because of the previous point that writing files will be as defragmented as possible
- When a file is frequently accessed but not modified, they will be moved to a special area on the hard disk which has the fastest access (again the process of moving these files will automatically defragment them)
- When a file has become exceedingly fragmented, the operating system will defragment it on the spot