You can! All of those filesystems you mentioned were created by people, and you can do it just the same way. It is, however, quite a lot of work to get something as good as any of those, let alone better. You’ve also hit on one of the problems - nothing else is going to support your filesystem.

If you’re interested in trying anyway, just out of curiosity, do a little research into FUSE, Filesystem in Userspace. FUSE is a tool that lets you write a filesystem without needing to integrate with the very low-level parts of the operating system, which takes some burden off of your implementation.

This is why I love Lemmy, I can ask this obscure, unrealistic question, and people will still answer it with the “yeah you probably shouldn’t but here’s how you could”

NTFS, fat32, exfat, could I theoretically create my own filesystem?

Yes. There are many different file systems and you can absolutely create your own. Making one that is reliable and performs well, and/or is something you can actually use for the disk that you boot from, generally involves low-level kernel programming and years of work - and is not exactly a beginner’s programming project.

However, you can also more easily play with implementing filesystems in a high-level language using FUSE.

If so would my computer even be able to work with most files or connect to other devices?

Your computer can use many different filesystems at the same time. You can also store a filesystem in a file on another filesystem, rather than dedicating a partition of a physical disk to it. So, yes, you can use a filesystem of your own design at the same time you are using other storage devices formatted with more common filesystems.

Building a filesystem essentially means linking a directory of filenames to physical blocks and handling CRUD operations. It’s not that hard. The hard part comes when you go beyond the basics to build something efficient with useful features. For example, fast access, journaling and fragmentation are all challenging topics. You can try without messing with the kernel by creating an in-memory filesystem (essentially a block of RAM) and playing with the I/O.

That’s how those filesystems came into existence: someone designed them.

Yes, you can write your own filesystem, and use it on your own drives.

Yes, you will continue to be able to use other filesystems, unless you intentionally remove them from the system.

Look up reiserfs.

You can do anything if you put your mind to it.

Lots of good answers, especially using FUSE for experimentation. One thing I’ll add is that if you just didn’t want to use any filesystem at all … you don’t have to!

At least in the Unix realm, a disk drive is just a bunch of contiguous blocks, and you can put whatever you want in them. Of course, Unix itself famously needs a filesystem for itself, but if you want to just store all your giant binary blobs – cryptocurrency block chain? – directly onto a drive without the pesky overhead or conveniences of a filesystem, that’s doable.

It’s not generally a useful idea to treat a disk drive as though it’s a tape drive, but it does work. And going further into that analogy, you can use “tar” to collect multiple files and fit them onto the drive, since a tarball preserves file metadata and the borders between files, but not much else. This is the original use of tar – “tape archive” – for storing Unix files onto tape, because the thought of using tape as working storage with a filesystem was – and still is – a terrible idea. And that’s basically the original impetus for a filesystem: it’s better than linear access media.

Yes you can, for example here is how to use internet pings as a file system:

yarrick/pingfs: Stores your data in ICMP ping packets https://github.com/yarrick/pingfs

People have and do, but the effort is ridiculous and requires some very high-level computer science or computer engineering skills.

Yeah take a look at TempleOS and it’s filesystem RedSea.

TempleOS is a rabbit hole in of itself, RIP Terry.

https://en.m.wikipedia.org/wiki/TempleOS

Anything can be a hard drive if you are creative enough.

Creating a drive format is the easy part; getting it generally supported is the hardest part.

Yeah you could. Noone else could would bother to use your usb/hdd/ssd with your file system unless you gave them the drivers.

While you are at it, might concentrate on defects of certain fs you don’t like. Personally I hate the NTFS path length limit. XFS handles it much better overall but individual file names are much more limited because nobody thought about Unicode.

Also you could probably fork some fs like XFS.

Yea, I made a shitty one in my undergrad Operating Systems class.