Linux – a vfat signature

linuxpartitionsignatureusbvfat

Recently, I have noticed that I cannot access my USB flash drive filesystem (it was of FAT type, as far as I can remember). Fedora did not mount it automatically and lsblk could not see the partition. So, I decided to create new partition (instead of wiping the device at first) with fdisk.

The process was straightforward (fdisk did not complain a bit), but I noticed that fdisk asks me as a last step about removing a thing called "vfat signature":

Created a new partition 1 of type 'Linux' and of size 7.3 GiB.
Partition #1 contains a vfat signature.

Do you want to remove the signature? [Y]es/[N]o:

I am aware that happily creating new partition in such a case may not be the best thing. I do not know yet, what I would like to/should do. However, nonetheless, primarily I am curious, so I would like to know:

  1. What is a "vfat signature"?
  2. What is the reason that fdisk detects it?
  3. What is the purpose that fdisk detects it?
  4. Is it somehow related to a term that I have encountered in the context of Windows, "disk signature"?
  5. Why would I like to remove it or not?

I have searched for a similar question here, but found only this question which does not answer my doubts.

Best Answer

The signature partition is basically a mark/beacon there is something there, and it is not empty. It also may identify a partition.

It is useful on the context of several utilities/OS to tell the partition has already data there.

Moving a partition size/recreating a partition is usually a non-destructive operation up to the point before formatting it.

So a signature warning is signalling you "There is already data here!...are you sure you want to go ahead?"

As for removing it or not, it depends on wether you are for instance resizing a partition or creating a partition anew. If you are creating a partition anew, obviously you may want to remove the signature, if you are resizing a partition you surely want to keep it.

The use of partition signatures is not exclusive to Linux.

From How to wipe a signature from a disk device on Linux with wipefs command

Each disk and partition has some sort of signature and metadata/magic strings on it. The metadata used by operating system to configure disks or attach drivers and mount disks on your system

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