@c Copyright (C) 1997, 1998 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.

@node GNU/Linux
@unnumbered Linux and the GNU Project

Many computer users run a modified version of the GNU system every
day, without realizing it.  Through a peculiar turn of events, the
version of GNU which is widely used today is more often known as
``Linux'', and many users are not aware of the extent of its
connection with the GNU Project.

There really is a Linux; it is a kernel, and these people are using
it.  But you can't use a kernel by itself; a kernel is useful only as
part of a whole system.  The system in which Linux is typically used
is a modified variant of the GNU system---in other words, a Linux-based
GNU system.

Many users are not fully aware of the distinction between the kernel,
which is Linux, and the whole system, which they also call ``Linux''.
The ambiguous use of the name doesn't promote understanding.

Programmers generally know that Linux is a kernel.  But since they
have generally heard the whole system called ``Linux'' as well, they
often envisage a history which fits that name.  For example, many
believe that once Linus Torvalds finished writing the kernel, his
friends looked around for other free software, and for no particular
reason most everything necessary to make a Unix-like system was
already available.

What they found was no accident---it was the GNU system.  The available
free software added up to a complete system because the GNU Project
had been working since 1984 to make one.  The GNU Manifesto
had set forth the goal of developing a free Unix-like system, called
GNU@.  By the time Linux was written, the system was almost finished.

Most free software projects have the goal of developing a particular
program for a particular job.  For example, Linus Torvalds set out to
write a Unix-like kernel (Linux); Donald Knuth set out to write a text
formatter (TeX); Bob Scheifler set out to develop a window system (X
Windows).  It's natural to measure the contribution of this kind of
project by specific programs that came from the project.

If we tried to measure the GNU Project's contribution in this way,
what would we conclude?  One CD-ROM vendor found that in their ``Linux
distribution'', GNU software was the largest single contingent, around
28% of the total source code, and this included some of the essential
major components without which there could be no system.  Linux itself
was about 3%.  So if you were going to pick a name for the system
based on who wrote the programs in the system, the most appropriate
single choice would be ``GNU''@.

But we don't think that is the right way to consider the question.
The GNU Project was not, is not, a project to develop specific
software packages.  It was not a project to develop a C compiler,
although we did.  It was not a project to develop a text editor,
although we developed one.  The GNU Project's aim was to develop
@emph{a complete free Unix-like system}.

Many people have made major contributions to the free software in the
system, and they all deserve credit.  But the reason it is @emph{a
system}---and not just a collection of useful programs---is because the
GNU Project set out to make it one.  We wrote the programs that were
needed to make a @emph{complete} free system.  We wrote essential but
unexciting major components, such as the assembler and linker, because
you can't have a system without them.  A complete system needs more
than just programming tools, so we wrote other components as well,
such as the Bourne Again SHell, the PostScript interpreter
Ghostscript, and the GNU C library.

By the early 90s we had put together the whole system aside from the
kernel (and we were also working on a kernel, the GNU Hurd, which runs
on top of Mach).  Developing this kernel has been a lot harder than we
expected, and we are still working on finishing it.

Fortunately, you don't have to wait for it, because Linux is working
now.  When Linus Torvalds wrote Linux, he filled the last major gap.
People could then put Linux together with the GNU system to make a
complete free system: a Linux-based GNU system (or GNU/Linux system,
for short).

Putting them together sounds simple, but it was not a trivial job.
The GNU C library (called glibc for short) needed substantial changes.
Integrating a complete system as a distribution that would work ``out
of the box'' was a big job, too.  It required addressing the issue of
how to install and boot the system---a problem we had not tackled,
because we hadn't yet reached that point.  The people who developed
the various system distributions made a substantial contribution.

The GNU Project supports GNU/Linux systems as well as @emph{the}
GNU system---even with funds.  We funded the rewriting of the
Linux-related extensions to the GNU C library, so that now they are
well integrated, and the newest GNU/Linux systems use the current
library release with no changes.  We also funded an early stage of the
development of Debian GNU/Linux.

We use Linux-based GNU systems today for most of our work, and we hope
you use them too.  But please don't confuse the public by using the
name ``Linux'' ambiguously.  Linux is the kernel, one of the essential
major components of the system.  The system as a whole is more or less
the GNU system.
