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diff --git a/winsup/doc/overview.xml b/winsup/doc/overview.xml new file mode 100644 index 000000000..f43a69719 --- /dev/null +++ b/winsup/doc/overview.xml @@ -0,0 +1,131 @@ +<?xml version="1.0" encoding='UTF-8'?> +<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"> + +<chapter id="overview" xmlns:xi="http://www.w3.org/2001/XInclude"> +<title>Cygwin Overview</title> + +<sect1 id="what-is-it"><title>What is it?</title> + +<para> +Cygwin is a Linux-like environment for Windows. It consists of a DLL +(<filename>cygwin1.dll</filename>), which acts as an emulation layer +providing substantial <ulink url="http://www.pasc.org/#POSIX">POSIX</ulink> +(Portable Operating System Interface) system call functionality, and a +collection of tools, which provide a Linux look and feel. The Cygwin DLL +works with all x86 and AMD64 versions of Windows NT since Windows XP SP3. +The API follows the +<ulink url="http://www.opengroup.org/onlinepubs/009695399/nfindex.html">Single +Unix Specification</ulink> as much as possible, and then Linux practice. +The major differences between Cygwin and Linux is the C library +(<literal>newlib</literal> instead of <literal>glibc</literal>). +</para> +<para> +With Cygwin installed, users have access to many standard UNIX +utilities. They can be used from one of the provided shells such +as <command>bash</command> or from the Windows Command Prompt. +Additionally, programmers may write Win32 console or GUI applications +that make use of the standard Microsoft Win32 API and/or the Cygwin API. +As a result, it is possible to easily port many significant UNIX +programs without the need for extensive changes to the source code. +This includes configuring and building most of the available GNU +software (including the development tools included with the Cygwin +distribution). +</para> +</sect1> + +<xi:include href="ov-ex-win.xml"/> +<xi:include href="ov-ex-unix.xml"/> + +<sect1 id="are-free"><title>Are the Cygwin tools free software?</title> + +<para>Yes. Parts are <ulink url="http://www.gnu.org/">GNU</ulink> software +(<command>gcc</command>, <command>gas</command>, <command>ld</command>, etc.), +parts are covered by the standard +<ulink url="http://www.x.org/Downloads_terms.html">X11 license</ulink>, +some of it is public domain, some of it was written by Red Hat and placed under +the <ulink url="http://www.gnu.org/licenses/gpl.html">GNU General Public +License</ulink> (GPL). None of it is shareware. You don't have to pay anyone to +use it but you should be sure to read the copyright section of the FAQ for more +information on how the GNU GPL may affect your use of these +tools. If you intend to port a proprietary application using the Cygwin +library, you may want the Cygwin proprietary-use license. +For more information about the proprietary-use license, please go to +<ulink url="http://www.redhat.com/services/custom/cygwin/">http://www.redhat.com/services/custom/cygwin/</ulink>. +Customers of the native Win32 GNUPro should feel free to submit bug +reports and ask questions through Red Hat channels. All other +questions should be sent to the project mailing list +<email>cygwin@cygwin.com</email>.</para> + +</sect1> + +<sect1 id="brief-history"><title>A brief history of the Cygwin project</title> + +<note> +<para> +A historical look into the first years of Cygwin development is +Geoffrey J. Noer's 1998 paper, "Cygwin32: A Free Win32 Porting Layer for +UNIX® Applications" which can be found at the <ulink +url="http://www.usenix.org/publications/library/proceedings/usenix-nt98/technical.html"> +2nd USENIX Windows NT Symposium Online Proceedings</ulink>. +</para> +</note> +<para> +Cygwin began development in 1995 at Cygnus Solutions (now part of Red Hat, +Inc.). The first thing done was to enhance the development tools +(<command>gcc</command>, <command>gdb</command>, <command>gas</command>, +etc.) so that they could generate and interpret Win32 native +object files. +The next task was to port the tools to Win NT/9x. We could have +done this by rewriting large portions of the source to work within the +context of the Win32 API. But this would have meant spending a huge +amount of time on each and every tool. Instead, we took a +substantially different approach by writing a shared library +(the Cygwin DLL) that adds the necessary UNIX-like functionality +missing from the Win32 API (<function>fork</function>, +<function>spawn</function>, <function>signals</function>, +<function>select</function>, <function>sockets</function>, etc.). We call this +new interface the Cygwin API. Once written, it was possible to build working +Win32 tools using UNIX-hosted cross-compilers, linking against this +library.</para> + +<para>From this point, we pursued the goal of producing Windows-hosted tools +capable of rebuilding themselves under Windows 9x and NT (this is +often called self-hosting). Since neither OS ships with standard UNIX +user tools (fileutils, textutils, bash, etc...), we had to get the GNU +equivalents working with the Cygwin API. Many of these tools were +previously only built natively so we had to modify their configure +scripts to be compatible with cross-compilation. Other than the +configuration changes, very few source-level changes had to be +made since Cygwin provided a UNIX-like API. Running bash with the development tools and user tools in place, +Windows 9x and NT looked like a flavor of UNIX from the perspective of +the GNU configure mechanism. Self hosting was achieved as of the beta +17.1 release in October 1996.</para> + +<para> +The entire Cygwin toolset was available as a monolithic install. In +April 2000, the project announced a +<ulink url="http://www.cygwin.com/ml/cygwin/2000-04/msg00269.html"> +New Cygwin Net Release</ulink> which provided the native non-Cygwin Win32 program +<command>setup.exe</command> to install and upgrade each package +separately. Since then, the Cygwin DLL and <command>setup.exe</command> +have seen continuous development. +</para> + +<para> +The biggest major improvement in this development is the 1.7 release in +2009, which dropped Windows 95/98/Me support in favor of using Windows +NT features more extensively. It adds a lot of new features like +case-sensitive filenames, NFS interoperability, IPv6 support and much +more.</para> + +<para>The latest big improvement is the 64 bit Cygwin DLL which +allows to run natively on AMD64 Windows machines. The first release +available in a 64 bit version is 1.7.19.</para> + +</sect1> + +<xi:include href="highlights.xml"/> +<xi:include href="new-features.xml"/> + +</chapter> |