Size vs Size On Disk - Basic Question.

[Vectraat]

So right now, I have a partially downloaded file that is showing under properties as:

 

Size: 9.32 GB

Size on disk: 64.0 KB

 

I'm trying to interpret what these two values mean in this specific context. I assume "Size on disk" means that I've downloaded only 64.0 KB onto my hard drive?

9.32 GB isn't the total size of this file in bytes either. So not sure what that value is supposed to mean

[tikker]

It has to do with how space is physically allocated on the disk:

https://superuser.com/questions/66825/what-is-the-difference-between-size-and-size-on-disk

 

If you allocate things in blocks of 512 KB, for example, everything that is between 1 and 512 KB in size will be 512 KB on disk.

[Vectraat]

1 minute ago, tikker said:

It has to do with how space is physically allocated on the disk:

https://superuser.com/questions/66825/what-is-the-difference-between-size-and-size-on-disk

Already read that link. I just want to know if Size on disk is the amount of data that's actually downloaded/available on the HDD I downloaded it to.

[tikker]

Just now, Vectraat said:

Already read that link. I just want to know if Size on disk is the amount of data that's actually downloaded/available on the HDD I downloaded it to.

Approximately yeah.

[KarathKasun]

Downloads usually go to a temp file with the "destination" file being an empty file.  Empty file on a disk with 64kb block size will be 64kb.

 

When the download completes the temp file is written over the empty destination file.

[Vectraat]

Just now, tikker said:

Approximately yeah.

Ok, so if I only have 64.0 KB downloaded on my hard drive, why does "size" say: 9.32 GB, especially since the file is over 50 GB. 

[tikker]

1 minute ago, KarathKasun said:

Downloads usually go to a temp file with the "destination" file being an empty file.  Empty file on a disk with 64kb block size will be 64kb.

 

When the download completes the temp file is written over the empty destination file.

Ah never really noticed this.

1 minute ago, Vectraat said:

Ok, so if I only have 64.0 KB downloaded on my hard drive, why does "size" say: 9.32 GB, especially since the file is over 50 GB. 

See @KarathKasun's answer. Size should slowly increase then as it continues.

[Vectraat]

1 minute ago, tikker said:

Ah never really noticed this.

See @KarathKasun's answer. Size should slowly increase then as it continues.

Ok, I think I understand now. 9.32 GB seems to be a trivial number because you haven't actually downloaded 9.32 It's kind've an estimate that will increase over time as you download.
What you really want to pay attention to is the 64.0 KB, because that's the size of the file that actually exists on the HDD - and that number will obviously increase over time as you download. 

[KarathKasun]

Just now, Vectraat said:

Ok, I think I understand now. 9.32 GB seems to be a trivial number because you haven't actually downloaded 9.32 It's kind've an estimate that will increase over time as you download.
What you really want to pay attention to is the 64.0 KB, because that's the size of the file that actually exists on the HDD - and that number will obviously increase over time as you download. 

Depends on browser/OS.  Sometimes the temp file is hidden in the file system.  In NTFS this can be a unallocated datastream on the disk.  So there is 9.2GB on the disk as temp data, but since its not allocated, the file is only technically taking up 64kb of "allocated space"

[tikker]

5 minutes ago, Vectraat said:

Ok, I think I understand now. 9.32 GB seems to be a trivial number because you haven't actually downloaded 9.32 It's kind've an estimate that will increase over time as you download.
What you really want to pay attention to is the 64.0 KB, because that's the size of the file that actually exists on the HDD - and that number will obviously increase over time as you download. 

If the 64 KB file is a temporary file then it will just jump from 64 KB to 50 GB once your download is finished. Windows is probably smart enough to read the "size" from the temporary directory where the file is being downloaded to, but the size of the file you are looking at is 64 KB on disk.

[KarathKasun]

1 minute ago, tikker said:

If the 64 KB file is a temporary file then it will just jump from 64 KB to 50 GB once your download is finished. Windows is probably smart enough to read the "size" form the temporary directory where the file is being downloaded to, but the size of the file you are looking at is 64 KB on disk.

Effectively.

[Vectraat]

1 minute ago, KarathKasun said:

Depends on browser/OS.  Sometimes the temp file is hidden in the file system.  In NTFS this can be a unallocated datastream on the disk.  So there is 9.2GB on the disk as temp data, but since its not allocated, the file is only technically taking up 64kb of "allocated space"

Using Chrome. It was an incomplete torrent download. So it went into a folder I designated as "incomplete"
But whether It's a torrent or a download via Chrome, it would still behave in the same way if you cancelled/paused the download. It'll still show as example: Size: 3.88 GB / Size on disk: 45.0. 
The 45.0 number/size on disk is the only number I really care about because that tells me how much of that file I've downloaded whether via my torrent client or Chrome.

[tikker]

5 minutes ago, Vectraat said:

Using Chrome. It was an incomplete torrent download. So it went into a folder I designated as "incomplete"
But whether It's a torrent or a download via Chrome, it would still behave in the same way if you cancelled/paused the download. It'll still show as example: Size: 3.88 GB / Size on disk: 45.0. 
The 45.0 number/size on disk is the only number I really care about because that tells me how much of that file I've downloaded whether via my torrent client or Chrome.

Except that it doesn't? Size: 3.88 GB / Size on disk: 45.0 means 3.88 GB has been downloaded somewhere, whereas 45 GB (assuming the same units since you didn't specify) has been allocated, which is just reserving space so that other programs don't use it.

[Vectraat]

2 minutes ago, tikker said:

Except that it doesn't? Size: 3.88 GB / Size on disk: 45.0 means 3.88 GB has been downloaded somewhere, whereas 45 GB (assuming the same units since you didn't specify) has been allocated, which is just reserving space so that other programs don't use it.

Ok, well, I don't know then. In the original example, I'm pretty sure I didn't download 9.32 GB of the file, because I paused it immediately when it started to download. So I don't think that can be accurate. 

[KarathKasun]

The 9.32gb is the pre-allocated space for the download then.