+ A <STRONG>tabs</STRONG> utility appeared in PWB/Unix 1.0 (1977), and thereafter in 3BSD
+ (1979). It supported a single "-n" option (to cause the first tab stop
+ to be set on the left margin). That option is not documented by POSIX.
+ Initially, <STRONG>tabs</STRONG> used built-in tables rather than the terminal database,
+ to support a half-dozen terminal types. It also had built-in logic to
+ support the left-margin, as well as a feature for copying the tab set-
+ tings from a file.
+
+ Later versions of Unix, e.g., SVr4, added support for the terminal
+ database, but kept the tables, as a fallback. In an earlier develop-
+ ment effort, the tab-stop initialization provided by <STRONG>tset</STRONG> (1982) and
+ incorporated into <STRONG>tput</STRONG> uses the terminal database,
+
+ POSIX documents no limits on the number of tab stops. Documentation
+ for other implementations states that there is a limit on the number of
+ tab stops. While some terminals may not accept an arbitrary number of
+ tab stops, this implementation will attempt to set tab stops up to the
+ right margin of the screen, if the given list happens to be that long.
+
+ The <EM>Rationale</EM> section of the POSIX documentation goes into some detail
+ about the ways the committee considered redesigning the <STRONG>tabs</STRONG> and <STRONG>tput</STRONG>
+ utilities, without proposing an improved solution. It comments that
+
+ no known historical version of tabs supports the capability of
+ setting arbitrary tab stops.
+
+ However, the <EM>Explicit</EM> <EM>Lists</EM> described in this manual page were imple-
+ mented in PWB/Unix. Those provide the capability of setting abitrary
+ tab stops.
+
+
+</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>