For example, even in the tiny copy program example, from the
introductory chapter, once you include the primitive getc and putc
subroutines, there are 7 symbolic constants: MAXLINE, MAXCARD,
NEWLINE, STDIN, STDOUT, EOF, SPACE and character, which is really
an integer and gets replaced with integer by some mythical
preprocessor (chapter 8). Anyhow, in the modern world, MAXLINE and
MAXCARD don't really have meaning, but they can magically be
treated as lines of a file, the rest do have meaning, but they
don't evaluate to the same things in Fortran-land as in
modern-land. STDIN is 5 and STDOUT is 6 (card reader and punch
LUNs, again some magic that lets them be treated as terminal input
and output), EOF is -1, SPACE is 32, NEWLINE is 10.
Pretty sure that EOF is _still_ -1. SPACE and NEWLINE also look pretty familiar and their values haven't changed, although we might spell them a little differently these days.