A dedicated NAS/FTP server does not use any MS OS or apps.
A couple of drives using SAMBA type NAS/FTP servers would work fine. You don't need to consolidate all 100 users on a single FTP server and many FTP servers don't handle 100 users simultaneously and do it very well.
If you send your customers a link to use it is fairly simple.
When I want someone to access an FTP server, a browser will accept the following format:
ftp://username:userpassword@serverurl.comOr if they just connect with
ftp://serverurl.com they will be prompted for a user name and password, which is quite normal and expected for a user/password type account.
The advantage of putting in "username:password" in the initial
ftp:// url is that it usually avoids having the server ask for the username and password multiple times as the user navigates his personal directories.
On the firefox browser, they can use the free addon called "fireftp" -- it looks a lot like the best FTP clients, with the user's directories on the left, and the ftp directories on the right. Files can easily be dragged from left to right, or right to left.
Using the "My Computer" in WIndows is even easier. Not the Microsoft internet browser, but go directly to the "my computer" program (windows explorer vs. internet explorer).
In the address bar, instead of navigating to a hard disk, have your clients simply type into the address line the URL to the ftp server. E.g.
ftp://username:userpassword@serverurl.comWhen you put this in the Windows "my computer" address line, it does in one step what might take two steps if going through the internet explorer. It immediately opens the FTP site, and for the client (your client) it looks like any other hard disk directory, and allows dragging files into it, and out of it, from another open window pointing to a drive on the user/client system.
I don't think I've missed your point, because I do what you're trying to do, and with users who are not sophisticated, and none of this requires buying an FTP client program, or knowing all that much about
how FTP works, except that they type in FTP where they used to type in HTTP
Just a different transfer protocol -- one for files, one for hypertext.
Give it a try.
Jeff