Informix

OS:

BIG class Windows NT, Novell Netware and UNIX commersial database server.
There are standalone versions for Windows 3.11 and Windows 95/98
Commersial licence
ODBC driver

Database name may include Infomix server name: database@InformixServer
For connecting to Informix server, you need to have valid "sqlhosts" file or valid settings into "setnet" utility.
You need to have setted up standard Informix environment variables too (INFOMIXDIR, INFOMIXSEVER etc.)
For more look at your Informix documentation (high recomended)
There are two major types of Informix databases:

Type	Subtype (Version)	Class	OS	Price
Informix Standard Engine	Informix SE	Strong, but limited	UNIX	Price about $500/USER. Available 1 USER version Free licence for Linux
Informix Online	Infomix Workstantion	small	Windows 3.11 Windows 95/98	Price more $600++/USER. N/A 1 USER version.
	Dynamic Server	medium, strong	Windows NT Novell Netware UNIX
	Universal server	strong, object oriented	Windows NT Novell Netware UNIX