USB support, why "Create a partition on the USB disk"

Hello, sorry if this is a really silly question.
But I am trying to setup USB support on my TP link C2600, after installed LEDE17.01.4
I read through the guide here https://lede-project.org/docs/user-guide/usb-drives

What I do not understand is: why do I need to "Create a partition on the USB disk" etc, I mean, my USB is already formatted and there are contents on it, so how can I set it up so I can simply plug in a USB and be able to read/write?

Thanks.

Disks come formatted with a Microsoft type file system such as FAT32 or NTFS. Better performance will be achieved by reformatting it to a Linux file system: ext4 or f2fs (that will of course lose access of any files already stored on the partition though). You are correct though that it usually isn't necessary to re-partition, since the factory will have set up one partition that is the whole size of the drive.

There are drivers for the Microsoft formats if you want to mount the disk as-is, but you will lose speed and also features like file owner and permission tags. It can't be used as a root disk, only data, since the owner and permission system is essential for OS files to work.

I'll add that you can create more than 1 partition on the USB stick (or pretty much any drive). Then you can format one of the partitions as ext4 for use with extroot or overlay on LEDE and the other(s) as FAT for Windows and Mac compatibility, and it can also work with LEDE (for data purposes only, as @mk24 mentioned) for access/sharing of data.

If you go this route, copy your data from the USB stick to somewhere else, partition and format, and then move the data back again. There are some utilities that can resize partitions on the fly (without needing to erase/reformat), but best not to tempt fate with any important data.

Thanks for the response.
However I think the most common use case is:

  • I have a usb with some files
  • I want to plug it to my router so:
    = it can be accessed by all windows PC in my home
    = it can be accessed by my iphone/ipad via VLC
    = it can be accessed by my android TV box via VLC

I do not care about user controls or permissions, I only want to access it from any device.

This can be done easily using stock firmware.

So maybe we need a simple tutorial on how to achieve above?

Thanks!