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I'm wanting to refine my understanding of what 'free space' is on a computer. Doing my background reading I've come to see that their are two instances in which 'free space' is referenced. I don't believe that they reference the same kind of 'free space' though.

First observation:

There is the free space on a HD. Say, you have C: or / partitioned at 10 GB and utilizing 3 GB for their respective OS. This leaves each with 7 GB of 'free space'

Second observation:

When partitioning your drives to make the most efficient use of your HD space, you partition your spaces 'into' a 'free space'. So you have a 30 GB HD, you partition 10 GB for C: and 10 GB for / (maybe a 2 GB swap) leaving you with 8 GB of 'free space'.


What happens with that remaining 8 GB of 'free space' NOT designated a partitioning preference. If I'm correct, this 'free space' wont be recognizable by your OS for you to utilize in some meaningful way.

Would someone so kindly give me an astute academic definition of HOW this 'free space' functions when undesignated.


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up vote 0 down vote accepted

Well, personally under Windows, I used to like making loads of partitions for every different thing - but it is so hard to plan in advance and I now simply have one large drive, it is so much easier to manage.

As for what happens, if any space is unassigned, it simply is unused and will go to waste.

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In your first example your "free space" is space allocated to a partition, with a file system on it, but does not contain any data on it yet. These type numbers show when you look at your drive properties and see the drive size, used and "free space". This space can be used by simply downloading, creating or modifying files to take up more space on the drive.

In the second example you are talking about unallocated space, which if left as such cannot be used by any OS or software to store files as there is no file system on the "free space". This type space can be later allocated as NTFS, FAT32, Ext3 or other file system.

Edit: I guess to answer your final question would be nice... The space is unused and will remain unused until a file system is placed on it like you mentioned. The read heads of the drive will skip over this section and move on to areas with file systems on them.

Say you put, for some reason, a 10gb unallocated section at the very beginning of the drive. The read heads will come from their parked position, skip over this 10gb area and then get to the data they are looking for. As data at the end of the drive is a little slower to access this would effect your data transfer speeds. Other than effecting speeds in this way the space would not have any other noticeable effects.

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Excellent, thank you. – Apollo Sep 1 '10 at 18:30

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