My gut reaction to this was "isn't that just sqlite"?
I don't think this is what you were thinking of, but I do kind of love the idea of formalizing sqlite file formats where the "metadata" is standardized and the "file" is stored inside. Like a file format for a recipe, or a picture, or ...
Isn’t that just a container format, like what video and audio files have used for decades?
I don’t know of any existing container formats with support for a relational DB as one of the embedded streams, but the whole point of container formats is that you can add arbitrary metadata, which of course can be a whole database.
Of course, the way BeOS does what OP is talking about is by having many DB columns within the filesystem itself! (The filesystem is a queryable database).
Yes, I totally get the distinction (and I was among those amazed by BeOS back in the day - I still show the old demo videos to friends who haven't seen it). I hadn't considered the container formats used by media, but in my head it would be the other way around - each file would be a sqlite file first so that they all share some commonality around access and inspection (I'm assuming in my ignorance that the media container formats are different).
Are there any database filesystems today? I haven't really looked, but the last one I heard of was the one that MS abandoned years ago. Actually I suppose Haiku probably still has one? I can't imagine how difficult it would be to get a DB Filesystem as a mainstream choice on Linux, let alone across OSen.
If you want something more tangible than old demos, try HaikuOS. It works wonderfully from a usb drive.
I’m too young to have known BeOS (well I was a kid in the nineties so not too young but afaik, BeOS was pretty rare (overall and) at home. However I’m old enough to have known OSes that were build around offline usage and that’s what I loved trying Haiku is that it remembers me when your OS was made to use your computer, not to be an internet client.
I feel that having your emails as files is a good example of that : you connect to the internet to get your mails. You disconnect. You want to work to those mails on another computer ? No problem, just copy paste them on a USB d… I mean floppy disk, answer your mails put the answers on your floppy disk and send them tonight when you’re back home.
It may feel pretty cumbersome when we have today’s tools but that’s the feeling I feel I lost : owning my data not only legally but physically. And not only physically but physically in a useful way.
It remembers me the time when you just had to understand simple abstractions like files and folders and windows to own the computer (and you were just learning some programming language away to master it).
Every filesystem is by definition a database system.
Out of extant systems, the closest to BeFS outside of Haiku is NTFS as implemented in Windows. In fact, you can run pretty much all of the BeOS behaviors on NT since ~1994 or so, it's an issue of programs not using it. Part of that is allegiance of user applications to Classic Windows-compatible APIs.[1] Part of the "WinFS" efforts was to break with the old approaches totally and push more indexed/searchable APIs etc. but in the end all we have is pretty robust internal search engine that is sadly underused (just like the extended attributes support). It really doesn't help that Explorer.exe is in many ways ridiculously outdated, with Windows95/98 peeking out from various corners when you look deeper into how it acts.[2]
Then ZFS but the ZPL/DMU APIs do not include indexing layer IIRC (also on systems that use Irix-style xattr APIs you lose full scope of resource forks).[3]
Both OS/2 (with HPFS) and OSX do some work with integrating metadata in filesystem, with various level of usage and end-user accessibility.
And of course there's some level of integration in AmigaOS Workbench and .info files, but that's arguably the most niche by now and never evolved to this level of use.
[1] Know the regular posts about how you can't create a file named "CON:" or "COM1:" etc in Windows? In Windows NT you actually can, but a) the only way to do it "safely" is to use alternate NTFS namespace b) I bet most people have never heard there was more than one namespace c) Win32 applications will usually only see Windows95 LFN-compatible one (in two versions, UCS and ASCII) unless they get out of their way to get access to other namespaces
[2] It's not the most egregious though - at least explorer.exe internally uses paths that work with default APIs of the system. In 2021 I ended up having to dig out an AppleScript for converting MacOS Classic paths to POSIX ones, because it turns out Finder AppleEvents API returned only Classic paths. Or at least neither I, or anyone I could find, knew how to get Finder to return a path that wasn't Classic HFS one
[3] Irix-style xattr API is limited in capabilities to only add short K/V data to a file. Solaris instead effectively gives you a complete directory attached to a file, while WindowsNT on NTFS treats everything including main content of file as "extended attribute" and opening file as normal is essentially "open the $DATA attribute of the file".
I don't think this is what you were thinking of, but I do kind of love the idea of formalizing sqlite file formats where the "metadata" is standardized and the "file" is stored inside. Like a file format for a recipe, or a picture, or ...