The Mac innovated many things in filing systems, and took paradigms much further.
Before Apple there was CLI's (command line interfaces). There was nothing like the Macs "Finder", and no one had represented files as icons before (this "making an icon behave like a file" may sound obvious, after the fact, but was a serious innovation for it's time).
Because to do things (like copy a file), you had to type in the entire file name (and path name), people used lots of abbreviations and concatenation to reduce typing. This is why CP/M (DOS) used 8.3 (8 charaters + a 3 character suffix). A few OSs (VAX/VMS) allowed for longer file names -- but some can't handle space and special symbols. Later in time CLIs added type completion (which means that if you type the first part, it will try to guess at the latter part -- and sometimes get it right) -- but still it means that you are trying to type as little as possible.
The Mac was the second mainstream microcomputer to allow long file names (31 characters). Apple DOS 3.2 in 1977 on an Apple][ is actually the first to have long file names -- and in 1983 it got upper and lower case. (Same time frame as the Lisa). There were minicomputers and mainframes that allowed long file names -- but Apple did mainstream it. The innovation went way beyond just more typing. The Mac also allowed spaces and special symbols. Since the CLIs had "wildcard" characters, like "*" or used "/" or "\" to denote path, you couldn't use those in a file name -- with the Mac you could.
There is one limitation on the Mac... no ":" (colon) in file or folder names. ":" is used to denote path. But still Apple spent the time to do things right. When in the finder, if you type ":", it just replaces it with "-", so people don't even notice the change.
It took Microsoft 12 years to support longer file names (until Windows95), and even then it couldn't handle most special symbols well, and it took another 3+ years until enough Applications supported things right that you didn't have to remember abbreviations for all your files anyway. (You still occasionally have to deal with 8.3 on Windows -- just far less often than in the past).
There were a few other Operating Systems that allowed upper and/or lower case -- but that usually means that they were case sensitive (and you had to type case perfectly), or they just ignored case and slammed it into all upper or all lower case. Case sensitive meant that you could ask for a file called "text.txt" and get an error because the files name was "Text.txt" -- very annoying to not only have to remember the files name, but also get the capitalization perfect. The other systems that ignored it would just always convert to upper or lower case, so if you named a file, "TheRe.txt", the system would just make it "there.txt" or "THERE.TXT". The Mac was the first computer I know of that allowed things to be case insensitive -- but still remembered the case properly. So if you ask for "ThisFile" on a Mac, and the file was named "thisFILE", it still finds the file -- and of course it saves the file in the proper case. Of course on the Mac you rarely (if ever) have to type in file names or paths -- but it does help when saving a file to know that "File 03/31/99" already exists, even if you typed "FILE 03/31/99".
And once again, the Mac designers didn't just stop with just improving on simple case issues. On the Mac you can save symbols like accents and many special characters (like an ascending accent over the e). So I can save a file named:. Notice the little acute accent over the e's. It is nice having these special symbols in file names, but what is better is if you were to ask the filing system for "Resume" it would know that the acute-e (aigu) is the same character as the e. So the filing system will find it -- how's that for smart and doing it right? On all other OS's they do not understand that an e with an accent is the same character as an e ( or a "u" with an umlaut was a 'u', and so on) -- but of course that doesn't matter since most still can't display things like this.
Now you might ask what use is this, but it certainly helped make the Mac multi-lingual (at least for Roman languages) as early as 1984 -- way before others caught on. And Apple pushed the boundaries with multi-lingual versions of the System, and is the most universal OS out there.
The point is that the Mac did it right, and innovated and thought of all sorts of things that other OS's still can't handle right -- 15+ years later.
Others OS's have different ways of handling different writing systems -- but the Mac is one of the most versatile I know of. NeXT did some neat stuff early on, as well as many other companies and computers -- but Apple was a pioneer. One of the sad things is that Apple figured out so many simple things correctly with Roman Text (and other writing Systems), that others have yet to get working properly.
It still bothers me that when I host a website with UNIX or NT I run into so many file naming problems (like not being case insensitive, or handling special characters well). Some of this is Apple's fault, for doing things better (different) -- but most of it is the fault of thinking that something is "good enough" when it can't anticipate the most obvious of users needs.