Output (Object) File
====================

   Every time you run `as' it produces an output file, which is your
assembly language program translated into numbers.  This file is the
object file, named `a.out' unless you tell `as' to give it another name
by using the `-o' option.  Conventionally, object file names end with
`.o'.  The default name of `a.out' is used for historical reasons:
older assemblers were capable of assembling self-contained programs
directly into a runnable program.

   The object file is meant for input to the linker `ld'.  It contains
assembled program code, information to help `ld' integrate the
assembled program into a runnable file, and (optionally) symbolic
information for the debugger.