Last issue, I mentioned that some readers said the reason why they haven't migrated off of NT 4 is because they are investigating moving to Linux as an alternative to upgrading to Windows Server 2003 (or even Windows 2000 Server).Is Linux a viable alternative or simply an idle threat in the hopes that it would force Microsoft to extend the deadline for NT 4 support beyond Jan. 1, 2005?The latest versions of SuSE, Red Hat, Fedora, Debian and other Linux distributions do have lower minimum hardware requirements than either Win 2000x (that is, Windows 2000 or Windows 2003) servers. But if all you really want is file-and-print, which is what Linux and Windows servers do out of the box, then you're just as well off sticking with NT 4. There's no expense at all in that case.Eventually though, there'll no longer be hardware available with NT 4 compatible drivers, so you will have to upgrade\/migrate at some point down the road. But most likely, that won't happen for a number of years.Database services can be provided by the Linux box equipped with MySQL or PostgreSQL. Still, there'll most likely be additional hardware (disk and\/or RAM) needed - database servers can rarely have too much of either.If your application is running against SQLServer on the NT 4 platform, then minimal changes should be necessary to get it working with MySQL or PostgreSQL. But there is an expense - however minimal - associated with the move. You might even be able to move up to a more recent version of the application, but that might require the authorization and authentication services of a full-blown directory service, which is not an NT 4 domain. You could add the open source OpenLDAP, though.Still, OpenLDAP is a full-blown directory service. It will require management and some additional knowledge. That doesn't come free; there is a price to pay even if that price is measured in your time.If your NT 4 server is running a Web server a move to Linux shouldn't be too difficult, especially if it's the Apache Web server - the one most frequently used worldwide. Apache is more tightly integrated with Linux than with Windows.Of course, if you're running Internet Information Server on NT 4 you still have the option of moving your Web site to Apache on Linux. But - as was the case with the database services I just mentioned - there is a learning mode. You - or your Web designers - may also need to learn a new Web design package or even new coding techniques. Best to figure in that cost when you're making your decision.Whatever service you're running on your NT 4 server could most likely be moved to a Linux box. But Linux is free in much the same manner as a "free cat" - there's a lot of overlooked expense. So before thumbing your nose at Microsoft, be sure to do all of your homework and identify all of the expenses involved in moving to a different platform. It still might make sense to do so, and there'll be fewer "gotchas" when you get there.