“Defragging” is short for “de-fragmenting” and it’s a process run on most hard drives to help make accessing the files on that disk faster.
Traditionally, it’s something you need to do periodically as files on the disk become more and more fragmented over time (hence, the term “defragmenting”).
So, what does it mean to be fragmented? Why does it get worse over time?
I’ll review that, as well as how to defragment
To defragment a disk drive is to physically rearrange the contents of the files stored on the disk so that they can be accessed more efficiently. '>defragment, when to defragment, and even if you need to worry about defragmenting at all.
The information stored in a single file may not necessarily be stored in one place. For a variety of reasons the data may be scattered in fragments kept in various locations around the surface of the disk. The file system keeps track of where all the fragments are so that when we use a file it behaves as one single thing. Traditional hard disks involve actual moving parts, so a file that is scattered around a disk’s surface will be slower to access than one where all the pieces are near each other. Defragmenting simply rearranges the pieces of files such that they are not only near each other, but also in order, so that reading the file can take place as quickly as possible. Disks without moving parts – such as flash drives and SSDs – typically do not benefit from defragmenting. (Click on the term for full definition.) Fragmentation
To you and me, a file on your disk is a single thing. You open it, you work on it, you save it. It’s a single entity. We might compare it to say a book.
To your computer, however, a file is a lot more like a bunch of pages in that book that it has to keep track of individually.
Imagine that you have a book, but that the pages are randomly scattered throughout your house. You have a list of where each page is, so when you want to read your book you go find page 1, then you look on the list for page 2 and go to that, then look up page 3, and so on. In order to read your book in order, you’re racing around the house like crazy because the pages are all over.
That’s a fragmented file. The sectors that make up the file are scattered all over the disk. The result is that when you access the file, Windows has to race all over the
disk to retrieve the whole thing. That takes time. Defragmentation
Defragmentation is nothing more than pulling all the pages/sectors together in order, so that they’re close to each other. In an ideally defragmented disk, the sectors of each file would be in an orderly sequence one right after the other, just like the pages in a book.
Now, UNlike the pages of a book strewn about your home, disk sectors are a little more limited in how they can be laid out. The result is that in order for the sectors of one file to be able to be arranged in a defragmented order, other files or fragments of files may have to be first moved out of the way to make room.
In fact, that’s what a defragmenting tool spends most of its time doing: moving files around on the disk to make room so that other files can be laid out in order.
It’s also one of the things that differentiates one disk defragmenting tool from another: some are simply better or more efficient at moving things around as little as possible so as to be done as quickly as possible with an result that’s as acceptable as possible.
Why fragmentation happens
Fragmentation happens because files on the disk are constantly changing; being created, deleted, grown, or shrunk in size. And all of that happens in a fairly random order.
For example purposes, let’s say we have a very tiny disk that has exactly 12 sectors and no more.
On this disk, we’ve created three files: file1, file2 and file3:
File 1 takes up two sectors, file 2 takes two, and file 3 takes up five sectors on the disk, leaving three sectors free at the end.
We now delete file 2:
As you can see, that leaves a “hole” of two empty sectors between the remaining files 1 and 3.
Now, we’ll create a new file, file 4, which is four sectors long:
The only way to store file 4 is to split it into two fragments: two sectors in part “(a)” and two sectors in part “(b)”.
It’s important to note that this all works just fine. The fact that files are fragmented is handled quite transparently by the operating system and the file system
File system (also “filesystem”, one word) is a term used to refer to the specific technique that allows files to be laid out and located on a hard disk or other random access storage device. '>file system. The various pieces of the files are all kept track of and located as needed.
At its most basic, a file system is nothing more than the specific format of the overhead information used to keep track of what data is stored where on a hard disk, and the rules used to place and locate that data. Since most hard disks and similar devices store data as files, then this is the “system” by which those “files” are placed on the media. In addition to defining exactly what gets stored where, file systems also define what capabilities are present, such as encryption, compression, the length of file names, the maximum size of files, and even whether or not file names can include both upper and lower case characters. File systems may also include information relating to security and permissions, allowing the operating system to control who may or may not perform operations on the files themselves. There are dozens, if not hundreds, of different file systems, but the two most common in Windows-based computers are the FAT (File Allocation Table) file system and NTFS (New Technology File System). The FAT file system predates Windows, but is still commonly used on Windows-compatible memory cards used on mobile and small devices, due to its comparative simplicity. NTFS is the more common file system for hard disks, due to its generally better performance, increased capacity, and the ability to support important aspects of data security. (Click on the term for full definition.)
It’s just that in our silly little example above if we want to read file 4 from end-to-end, we need to spend a little time “skipping over” file 3. If file 4 were in one contiguous set of sectors, it’d be a tiny bit faster.
Making that happen is what defragging is all about.2
But do I need to defragShort for: defragment.
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