What is the factor/formula?

[einstein9]

Dear Experts,

One question came to my mind once about How HDD/OS writes, i was thinking about How or Who decides this Specific File (for example) will be written to that specific sector?
Anyone knows?

is it based on a formula/OS/FS? or how its been calculated?

sometimes you see the HDD is filled with data from the beginning then Empty Space (zeros) then again data

i was wondering how?

Thank you

[einstein9]

None?

[sourcerer]

That formula is well hidden inside the filesystems (or more specifically the filesystem implementations). Every filesystem has its own formula. And that's the main job of a filesystem to decide where things go. For some filesystems there are even tools like defragmentation which can change the position afterwards.

[einstein9]

That formula is well hidden inside the filesystems (or more specifically the filesystem implementations). Every filesystem has its own formula. And that's the main job of a filesystem to decide where things go. For some filesystems there are even tools like defragmentation which can change the position afterwards.

And to add to this the drive itself will decide what LBA (sector) will belong to each physical location ...

Meaning the file system will tell what LBAs a file will be stored to and the drive itself will "translate" those LBAs to physical place on platter.

Any Base/Ref. to all of this? prefer if Technical Doc. not some sort of essay written by some dump or none-tech. person.

Am asking in general because am doing some research about something else, but this Question came to my mind

I tried reading many articles/docs none was helpful..

Thank you

[sourcerer]

In case of Linux filesystems, you can get the sourcecode on www.kernel.org :

For FAT:
https://git.kernel.org/pub/scm/linux/ke ... 9-rc6#n263

For EXT2:
https://git.kernel.org/pub/scm/linux/ke ... =v4.19-rc6
https://git.kernel.org/pub/scm/linux/ke ... 9-rc6#n259