Unix

Unix is a family of operating systems conforming to the Single Unix Specification, ultimately based on the original AT&T Unix. Unix clones such as BSD and Linux follow most of the specification. Unix is a trademark of The Open Group; most Unix clones are not Unix.

Origin of the roguelike genre

Unix is the origin of the C programming language, the curses library and the roguelike genre of games. Rogue is a Unix program in C and curses; so are Hack and Larn and Umoria. Today, both Angband and NetHack have Unix and curses as one of the supported platforms.

Today, the Unix clones called FreeBSD, NetBSD, OpenBSD, Minix, OpenSolaris and GNU/Linux are freely available. Many players and developers use them.

Source-compatible

The source code of a C and curses program made for Linux should compile above FreeBSD, and vice versa, with at most minor changes.

In the 1980s, the many BSD and SYSV variants introduced incompatibilities to Unix, but the Single Unix Specification has brought more uniformity to things. Most functions that a roguelike programmer needs should be everywhere. For example, you can use the random function to generate random numbers, and srandom and time to seed the random number generator; you would include stdlib.h and time.h. A roguelike developer can program for one flavor of Unix and not worry about the others.

The main difference is that Linux and Darwin users will link with -lncurses while most other Unix users will link with -lcurses. Obviously this is irrelevant if the program does not use curses.

The worst portability problems happen if you need to create a pseudo-terminal (as sshd and xterm do) or networking interface. Roguelike games can avoid this mess.

Not binary-compatible

There is no single Unix binary format. If you want Unix users to play your roguelike game, then you should provide source code.

OpenSolaris and Minix users cannot run Linux binaries. Most Linux binaries are usually Linux/x86 binaries, so Linux users with Alpha, PowerPC Macintosh, or Sparc hardware cannot run them either.

Some NetBSD/x86 users can load Linux/x86 binaries through binary emulation. This requires some setup, including the installation of many GNU/Linux packages on the NetBSD system. Users of NetBSD's 16 other architectures cannot do this.

Diversity of interfaces

Unix has a diverse set of libraries and environments to program in. Angband, NetHack, and their variants take the most advantage of this, providing multiple frontends or window ports.

The graphical environment on most Unix systems is the X Window System, Version 11. The main-x11.c frontend for Angband draws the game using X11, enabling new features like tiles and multiple windows. The x11 window port of NetHack provides similar features, but requires the Xaw widget set bundled with XFree86 or Xorg.

Qt and SDL interfaces to both Angband and NetHack also exist. Both Qt an SDL are portable across X11, Mac OS, and Microsoft Windows! Qt and SDL also add features that plain ancient X11 lacks.