VIM is Vi IMproved, a programmers text editor.
VIM runs on many operating systems:
AmigaOS, AtariMiNT, BeOS, DOS, MacOS, MachTen, OS/2, RiscOS, VMS, and Windows (95/98/NT4/NT5/2000)
and, of course, on UNIX in a lot of flavours:
A/UX, AIX, BSDI, Convex, DYNIX/ptx, DG/UX, DEC Unix, FreeBSD, HPUX, Irix, Linux [[[Debian]], RedHat, Slackware, SuSE,...], MacOSX, NetBSD, NEXTSTEP, OpenBSD, OSF, QNX, SCO, Sinix, Solaris, SunOS, SUPER-UX, Ultrix, Unixware, Unisys.
And the best of all: VIM is FREE! :-)
Please note: The source code to "vi" is copyrighted. Therefore the system like BeOS, FreeBSD, OpenBSD, and Linux can only give you "clones" of the original vi. So why would you want to use a vi clone? Well, please read about the many reasons to use a vi clone.