I attached a file to show my lack of understanding about the word allocated.
If you drew a Venn diagram, it would be the reverse of my perception about TreeSize.
For example, Windows is 20 GB but only allocated 9 GB or, 9 GB is put aside for it. How can the larger fit in the smaller. Does it mean there are 9 more GB's left for it.
I am not an expert, but in your case "Allocated" indicates the actual disk space used from a file.
The difference between "Size" and "Allocated" column has to do about the hardware architecture of your Hard Drive, how your hard drive saves files.
"Size" is memory space a file needs.
"Allocated" memory space is how much space your computer used to store that file.
More specific:
Your Drive uses 4096 Bytes per cluster (you can see that on the bottom right corner of your picture).
-Every file is saved to 1 or more clusters depending on it's size.
-You cannot share a cluster with another file.
There are 2 major cases of what will happen.
Case 1: "Allocated" space is more than "Size".
Case 2: "Allocated" space is less than "Size".
CASE 1
For example check the $SysReset file on your picture.
Let's analyse the difference between "Size" and "Allocated" Space here:
1)$SysReset needs 490 Bytes (Indicated in "Size") to be saved on your Hard Drive.
2)Your system saves data in clusters of 4096 Bytes each.
3)490 Bytes can be put in 1 cluster. So, $SysReset is saved in one cluster.
4)The cluster used to have 4096bytes of space. Minus 490 Bytes (from $SysReset) leaves 3606 Bytes.
5)Your computer cannot save anything in that 3606 Bytes, so that's 3096 Bytes (3 KB) of unused, wasted memory space.
6)Taking that into consideration means that $SysReset actually takes 4KB of space in your Hard Drive(490Bytes of file PLUS 3606 wasted memory space), thus the "Allocated" column.
To sum up:
The actual memory space a file needs is indicated in "Size", but due to the way your Hard Drive stores data (Hard Drive architecture) you do not always use memory space efficiently. So "Allocated" shows the space your Hard Drive used.
Simple example:
It's like you had an empty shelf on your kitchen.
It can contain 10 cans of food.
You buy 5 cans of tuna and place them on the shelf.
But, for some reason you will not put anything else on that shelf.
You end up having half the shelf empty and unused.
The Size is 5 can.
Wasted Space is 5 cans.
Allocated space is 10 cans.
So, generally Allocated memory space will be bigger than the actual size of your file.
You might think "wow, Hard Drives are pretty dumb to waste space like that".
But, wait, what about "Windows" file?
"Allocated" space is less than original "Size".
CASE 2
Well, that's where NTFS file system comes. You have it, check the parenthesis on the bottom right corner.
What does it do?
It saves memory space by a variety of ways. Most usual is by compressing files and then it can read/use them without de-compressing them.
So, in some cases, your computer will use a smart way to store a file. I, unfortunately, do not know when that happens, but you get the idea.
So, when you want to save a file on your computer, your computer makes 3 steps:
(Original Size of a file) –> (Process the file via a file system) –> (Allocated Size of a file within your Hard Disk).
Note: File system is the protocol/way your computer stores and retrieves data.
There is a line, that computer stores your data efficiently and not efficiently. Case 1 was not efficient use of space, while case 2 was efficient use of space.
Last thoughts on subject:
You should always check the "Allocated" column about how much space is consumed.
If there is an option to hide the "Size" column, do it. At least, I would. I don't need to know the actual "Size" of a file, what matters is how much space was used in the end ("Allocated").
Although, I must admit that TreeSize has this extra column ("Size") to show users what really happens with their files. And answer questions like: "Hey, on the Windows system requirements page states that Windows need 20 GB, why is my computer showing less? Was I scammed?"
Thanks for reading this huge post. I hope you've found it helpful.
I overlooked that word as I didn't know what it meant, that's why I never used it.
Allot, according to merriam-webster dictionary, means:
1)to assign as a share or portion
for example, allot 10 minutes for the speech
2)to distribute by or as if by lot
for example, allot seats to the press
While allocate is defined as:
1)to apportion for a specific purpose or to particular persons or things: distribute
for example, allocate tasks among human and automated component
2)to set apart or earmark: designate
for example, allocate a section of the building for special research purpose.
These 2 words have sometimes the same meaning. I read some people arguing about their difference and in computer science there is a difference.
I'll try to explain myself:
The Hard Disk has, by default, certain storage capabilities. This storage is "allotted", we don't know in what amount, among other programs/files etc. Also, this storage is "allotted" to equal sectors and clusters of sectors for practical reasons.
Files need some memory space from the Hard Disk. That memory space is preset. Predefined. Your computer "allocates" this predefined amount of memory for the file to the Hard Drive.
Note that (in computer science at least) "allocation" is used as a synonym for "assign" or "designate", while "allot" is mostly used as a synonym for "distribute" or "divide".
I urge you to read again my explanation, changing the words:
1)allot–>distribute/divide
2)allocate–>assign
Hey, please re-read my explanation, it will help!
I hope you have, by now, understood the difference in my example.
These 2 words may both be used in the above example, since they contain the meaning of both usages. But, it is established to use these words as stated above. Maybe to avoid confusion, maybe not. Who knows.
I hope I helped. If there is something you still haven't got, I would be glad to post some visual examples.
