\font\manual=manfnt % font used for the METAFONT logo and special symbols
 \newcommand{\bs}{\char '134}   % backslash for tt fonts
 \newcommand{\ALW}{Apple LaserWriter}
 \newcommand{\AmSTeX}{%
 $\cal A$\kern-.1667em\lower.5ex\hbox{$\cal M$}\kern-.125em$\cal S$-\TeX}
 \newcommand{\BG}{BBN BitGraph\INDEX{bbn bitgraph}{BBN BitGraph}}
 \newcommand{\C}{C}
 \newcommand{\CANON}{Canon\INDEX{canon}{Canon}}
 \newcommand{\CF}[1]{{\tt #1()}%
        \INDEX{#1}{\string\CFNX{#1}}}          % a C function name
 \newcommand{\CFNX}[1]{{\tt #1()}}
 \newcommand{\CN}[1]{{\tt #1}%
        \INDEX{#1}{\string\CNNX{#1}}}          % a C name
 \newcommand{\CNNX}[1]{{\tt #1}}
 \newcommand{\DEC}{DEC}
 \newcommand{\FN}[1]{{\tt #1}%
        \INDEX{#1}{\string\tt\space #1}}        % a file name
 \newcommand{\FNNX}[1]{{\tt #1}}
 \newcommand{\HCF}[1]{#1()}     % a C function name in a section header
 \newcommand{\HPLJ}{Hewlett-Packard LaserJet%
        \INDEX{hewlett-packard laserjet}{Hewlett-Packard LaserJet}}
 \newcommand{\HPUX}{HPUX\INDEX{hpux}{HPUX}}
 \newcommand{\IBMPC}{IBM PC\INDEX{ibm pc}{IBM PC}}
 \newcommand{\IMAGEN}{Imagen\INDEX{imagen}{Imagen}}
 \newcommand{\KCC}{KCC-20\INDEX{kcc-20}{KCC-20}}
 \newcommand{\LATTICE}{Lattice\INDEX{lattice}{Lattice}}
 \newcommand{\MAC}{Apple Macintosh\INDEX{apple macintosh}{Apple Macintosh}}
 \newcommand{\makeunderscorenormal}{\catcode`\_=8}
 \newcommand{\makeunderscoreletter}{\catcode`\_=11}
 \newcommand{\MICROSOFT}{Microsoft\INDEX{microsoft}{Microsoft}}
 \newcommand{\MF}{{\manual META}\-{\manual FONT}}
 \newcommand{\N}[1]{{#1}\INDEX{#1}{#1}}
 \newcommand{\PASCAL}{Pascal\INDEX{pascal}{Pascal}}
 \newcommand{\PCC}{PCC-20\INDEX{pcc-20}{PCC-20}}
 \newcommand{\PCDOS}{PC-DOS\INDEX{pc-dos}{PC-DOS}}
 \newcommand{\PLOT}{{\mbox{\raise.2ex\hbox{$<$}\kern-.1em\hbox{PLOT79}
    \kern-.1em\hbox{\raise.2ex\hbox{$>$}}}}}
 \newcommand{\POSTSCRIPT}{Post\-Script\INDEX{postscript}{Post\-Script}}
 \newcommand{\SUNOS}{SUN-OS\INDEX{sun-os}{SUN-OS}}
 \newcommand{\TANGLE}{Tangle\INDEX{tangle}{Tangle}}
 \newcommand{\TEKTRONIX}{Tektronix\INDEX{tektronix}{Tektronix}}
 \newcommand{\TOPS}{TOPS-20\INDEX{tops-20}{TOPS-20}}
 \newcommand{\TWENTY}{DEC-20\INDEX{dec-20}{DEC-20}}
 \newcommand{\UNIX}{Unix\INDEX{unix}{Unix}}
 \newcommand{\VAX}{VAX\INDEX{vax}{VAX}}
 \newcommand{\VMS}{VMS\INDEX{vms}{VMS}}
 \newcommand{\WEAVE}{Weave\INDEX{weave}{Weave}}
 \newcommand{\WEB}{Web\INDEX{web}{Web}}
 \newcommand{\WIZARD}{Wizard\INDEX{wizard}{Wizard}}
%
 \newcommand{\X}[1]{{#1}\INDEX{#1}{#1}} % shorthand for common indexing tasks
% ======================================================================
% NB: In this document, underscore is a normal letter except where
% turned back to its subscript function by \makeunderscorenormal
% ======================================================================
\makeunderscoreletter