Text games are typically easy to write and require less processing power than games with graphics, and thus were more common from 1970 to 1990. However, terminal emulators are still in use today, and people continue playing MUDs (multi-user dungeon) and exploring interactive fiction. Many beginning programmers still create these types of games to familiarize themselves with a programming language, and contests even now are held on who can finish programming a roguelike within a short time period, such as seven days.
While many of the earliest computer games (Adventure, Zork) relied on language parsing due to the command line-driven, teletype-terminal mainframe environments in which they were developed, the phrase "text-based" is taken to refer not to the user input (though generally keyboard-based) but rather to exclusive use of the fixed-width character display mode , an important distinction to maintain in light of curses based games such as Rogue and their successors, which employed the characters in the text mode as map symbols rather than as parts of words. Despite enormous differences in display and user interface, the text adventure games and roguelikes both make exclusive use of the text mode, and hence are both to be considered text-based.
Though punctuation and the alphanumeric symbols can be considered standard in most text modes, many of them contain additional symbols and variant attributes (colours, blinking, lines / columns per screen, etc.) that differ between operating environments: the text mode of a Commodore 64 would be substantially different from that of an IBM PC, though despite an absence of standardization in the text display (until implementation of later text mode terminal display standards such as VT100 and ANSI), they would both be considered to be text modes. These later standards also contain numerous characters, largely blocks and lines, specifically intended to be used for fast, low-bandwidth display of crude block graphics in the text mode.
Popular text-based adventure games include Zork and The Hitchhiker's Guide to the Galaxy.