13be28aa34
use &os.numports; instead of a hardcoded Ports number, and note that `Alpha' is a supported architecture up to version 6.X of FreeBSD.
1055 lines
43 KiB
Text
1055 lines
43 KiB
Text
<!DOCTYPE article PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [
|
|
<!ENTITY % articles.ent PUBLIC "-//FreeBSD//ENTITIES DocBook FreeBSD Articles Entity Set//EN">
|
|
%articles.ent;
|
|
]>
|
|
|
|
<article>
|
|
<articleinfo>
|
|
<title>Building Products with FreeBSD</title>
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Joseph</firstname>
|
|
<surname>Koshy</surname>
|
|
<affiliation>
|
|
<orgname>The FreeBSD Project</orgname>
|
|
<address><email>jkoshy@FreeBSD.org</email></address>
|
|
</affiliation>
|
|
</author>
|
|
</authorgroup>
|
|
|
|
<pubdate>$FreeBSD$</pubdate>
|
|
|
|
<legalnotice id="trademarks" role="trademarks">
|
|
&tm-attrib.freebsd;
|
|
&tm-attrib.general;
|
|
</legalnotice>
|
|
|
|
<abstract>
|
|
<title>Abstract</title>
|
|
|
|
<para>The FreeBSD project is a worldwide, voluntary, and
|
|
collaborative project, which develops a portable and high-quality
|
|
operating system. The FreeBSD project distributes the source
|
|
code for its product under a liberal license, with the
|
|
intention of encouraging the use of its code. Collaborating
|
|
with the FreeBSD project can help organizations reduce their
|
|
time to market, reduce engineering costs and improve their
|
|
product quality.</para>
|
|
|
|
<para>This article examines the issues in using FreeBSD code in
|
|
appliances and software products. It highlights the
|
|
characteristics of FreeBSD that make it an excellent substrate
|
|
for product development. The article concludes by suggesting a
|
|
few <quote>best practices</quote> for organizations
|
|
collaborating with the FreeBSD project.</para>
|
|
</abstract>
|
|
</articleinfo>
|
|
|
|
<sect1 id="introduction">
|
|
<title>Introduction</title>
|
|
|
|
<para>FreeBSD today is well-known as a high-performance server
|
|
operating system. It is deployed on millions of web servers and
|
|
internet-facing hosts worldwide. FreeBSD code also forms an
|
|
integral part of many products, ranging from appliances such as
|
|
network routers, firewalls, and storage devices, to personal
|
|
computers. Portions of FreeBSD have also been used in
|
|
commercial shrink-wrapped software (see
|
|
<xref linkend="freebsd-intro">).</para>
|
|
|
|
<para>In this article we look at the <ulink
|
|
url="&url.base;/">FreeBSD project</ulink> as a software
|
|
engineering resource—as a collection of building blocks
|
|
and processes which you can use to build products.</para>
|
|
|
|
<para>While FreeBSD's source is distributed freely to the public,
|
|
to fully enjoy the benefits of the project's work, organizations
|
|
need to <emphasis>collaborate</emphasis> with the project. In
|
|
subsequent sections of this article we discuss effective means
|
|
of collaboration with the project and the pitfalls that need to
|
|
be avoided while doing so.</para>
|
|
|
|
<sect2>
|
|
<title>Target Audience</title>
|
|
<para>This document would be of interest to the following broad
|
|
groups of people:</para>
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara>Decision makers in product companies looking at
|
|
ways to improve their product quality, reduce their time
|
|
to market and lower engineering costs in the long
|
|
term.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Technology consultants looking for best-practices
|
|
in leveraging <quote>open-source</quote>.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Industry observers interested in understanding the
|
|
dynamics of open-source projects.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Software developers seeking to use FreeBSD and
|
|
looking for ways to contribute back.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>Article Goals</title>
|
|
<para>After reading this article you should have:</para>
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara>An understanding of the goals of the FreeBSD
|
|
Project and its organizational structure.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>An overview of the available technology in the
|
|
project.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>An understanding of its development model and
|
|
release engineering processes.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>An understanding of how conventional corporate
|
|
software development processes differ from that used in
|
|
the FreeBSD project.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Awareness of the communication channels used by the
|
|
project and the level of transparency you can
|
|
expect.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Awareness of optimal ways of working with the
|
|
project—how best to reduce engineering costs,
|
|
improve time to market, manage security vulnerabilities,
|
|
and preserve future compatibility with your product as the
|
|
FreeBSD project evolves.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>Article Structure</title>
|
|
<para>The rest of the article is structured as follows:</para>
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara><xref linkend="freebsd-intro"> introduces the
|
|
FreeBSD project, explores its organizational structure,
|
|
key technologies and release engineering
|
|
processes.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara><xref linkend="freebsd-collaboration"> describes
|
|
ways to collaborate with the FreeBSD project. It examines
|
|
common pitfalls encountered by corporates working with
|
|
voluntary projects like FreeBSD.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara><xref linkend="conclusion"> concludes.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</sect2>
|
|
</sect1>
|
|
|
|
<sect1 id="freebsd-intro">
|
|
<title>FreeBSD as a set of building blocks</title>
|
|
|
|
<para>FreeBSD makes an excellent foundation on which to build
|
|
products:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara>FreeBSD source code is distributed under a liberal
|
|
BSD license facilitating its adoption in commercial products
|
|
<citation>Mon2005</citation> with minimum hassle.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>The FreeBSD project has excellent engineering
|
|
practices that can be leveraged.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>The project offers exceptional transparency into its
|
|
workings, allowing organizations using its code to plan
|
|
effectively for the future.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>The culture of the FreeBSD project, carried over from
|
|
the Computer Science Research Group at The University of
|
|
California, Berkeley <citation>McKu1999-1</citation>,
|
|
fosters high-quality work. Some features in FreeBSD define
|
|
the state of the art.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<simpara><citation>GoldGab2005</citation> examines the business
|
|
reasons for using open-source in greater detail. For
|
|
organizations, the benefits of using FreeBSD components in their
|
|
products include a shorter time to market, lower development
|
|
costs and lower development risks. </simpara>
|
|
|
|
<sect2>
|
|
<title>Building with FreeBSD</title>
|
|
|
|
<simpara>Here are a few ways organizations have used
|
|
FreeBSD:</simpara>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara>As an upstream source for tested code for libraries
|
|
and utilities.</simpara>
|
|
<simpara>By being <quote>downstream</quote> of the project,
|
|
organizations leverage the new features, bug fixes and
|
|
testing that the upstream code receives.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>As an embedded OS (for example, for an OEM router
|
|
and firewall device). In this model, organizations use a
|
|
customized FreeBSD kernel and application program set
|
|
along with a proprietary management layer for their
|
|
device. OEMs benefit from new hardware support being added
|
|
by the FreeBSD project upstream, and from the testing that
|
|
the base system receives.</simpara>
|
|
<simpara>FreeBSD ships with a self-hosting development
|
|
environment that allows easy creation of such
|
|
configurations.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>As a Unix compatible environment for the management
|
|
functions of high-end storage and networking devices,
|
|
running on a separate processor <quote>blade</quote>.</simpara>
|
|
<simpara>FreeBSD provides the tools for creating dedicated
|
|
OS and application program images. Its implementation of
|
|
a BSD unix API is mature and tested. FreeBSD can also
|
|
provide a stable cross-development environment for the
|
|
other components of the high-end device.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>As a vehicle to get widespread testing and support
|
|
from a worldwide team of developers for non-critical
|
|
<quote>intellectual property</quote>.</simpara>
|
|
<simpara>In this model, organizations contribute useful
|
|
infrastructural frameworks to the FreeBSD project (for
|
|
example, see &man.netgraph.3;). The widespread
|
|
exposure that the code gets helps to quickly identify
|
|
performance issues and bugs. The involvement of
|
|
top-notch developers also leads to useful extensions to
|
|
the infrastructure that the contributing organization also
|
|
benefits from.</simpara>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<simpara>As a development environment supporting
|
|
cross-development for embedded OSes like <ulink
|
|
url="http://www.rtems.com/">RTEMS</ulink> and <ulink
|
|
url="http://ecos.sourceware.org/">eCOS</ulink>.</simpara>
|
|
<simpara>There are many full-fledged development environments
|
|
in the &os.numports;-strong collection of applications ported and
|
|
packaged with FreeBSD.</simpara>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<simpara>As a way to support a Unix-like API in an otherwise
|
|
proprietary OS, increasing its palatability for
|
|
application developers.</simpara>
|
|
<simpara>Here parts of FreeBSD's kernel and application
|
|
programs are <quote>ported</quote> to run alongside
|
|
other tasks in the proprietary OS. The availability of a
|
|
stable and well tested <trademark>Unix</trademark> API
|
|
implementation can reduce the effort needed to port
|
|
popular applications to the proprietary OS. As FreeBSD
|
|
ships with high-quality documentation for its internals
|
|
and has effective vulnerability management and release
|
|
engineering processes, the costs of keeping upto-date are
|
|
kept low.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</sect2>
|
|
|
|
<sect2 id="freebsd-technologies">
|
|
<title>Technologies</title>
|
|
|
|
<para>There are a large number of technologies supported by the
|
|
FreeBSD project. A selection of these are listed
|
|
below:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara>A complete system that can cross-host itself for
|
|
the following architectures: alpha (up to &os; version 6.X), amd64, ia64, i386,
|
|
sparc64, powerpc (see &man.build.7;).</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Support for the following technologies, protocols
|
|
and standards: <!-- Keyword soup. Urk. -->
|
|
<acronym>ATA</acronym>, <acronym>ATAPI</acronym>,
|
|
<acronym>ATM</acronym>, <trademark>Bluetooth</trademark>,
|
|
<acronym>CAM</acronym>, <trademark>CardBus</trademark>,
|
|
<acronym>DHCP</acronym>, <acronym>DNS</acronym>,
|
|
<trademark>EISA</trademark>,
|
|
<trademark>Ethernet</trademark>, <acronym>FDDI</acronym>,
|
|
Fibre Channel, <acronym>GPIB</acronym>, IEEE 1394, IPv4,
|
|
IPv6, <acronym>IPSEC</acronym>,
|
|
<trademark>IPX</trademark>, <acronym>ISDN</acronym>,
|
|
<acronym>MAC</acronym>, <acronym>NIS</acronym>,
|
|
<acronym>NFS</acronym>, OpenSSH, <acronym>OPIE</acronym>,
|
|
<acronym>PAM</acronym>, <trademark>PCI</trademark>,
|
|
<acronym>PCMCIA</acronym>, <trademark>POSIX</trademark>,
|
|
<acronym>PnP</acronym>, <acronym>RAID</acronym>,
|
|
<acronym>RPC</acronym>, <acronym>SATA</acronym>,
|
|
<acronym>SCSI</acronym>, <acronym>SMB</acronym>,
|
|
<acronym>TCP</acronym>, <acronym>USB</acronym>,
|
|
<acronym>VESA</acronym>, <acronym>VLAN</acronym>,
|
|
<acronym>VLB</acronym>,
|
|
<trademark>WebNFS</trademark>.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>A modular symmetric multiprocessing capable kernel,
|
|
with loadable kernel modules and a flexible and easy to
|
|
use configuration system.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Support for emulation of
|
|
<trademark>Linux</trademark> and SVR4 binaries at near
|
|
machine speeds. Support for binary
|
|
<trademark>Windows</trademark> (<acronym>NDIS</acronym>)
|
|
network drivers.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Libraries for many programming tasks: archivers,
|
|
FTP and HTTP support, thread support, in addition to a
|
|
full <trademark>POSIX</trademark> like programming
|
|
environment.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Advanced security features: Mandatory Access
|
|
Control (&man.mac.9;), jails (&man.jail.2;),
|
|
<acronym>ACL</acronym>s, and in-kernel
|
|
cryptographic device support.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Advanced networking features: firewall-ing, QoS
|
|
management, high-performance TCP/IP networking with
|
|
support for many advanced features.</simpara>
|
|
<simpara>FreeBSD's in-kernel Netgraph (&man.netgraph.4;)
|
|
framework allows kernel networking modules to be connected
|
|
together in flexible ways.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Support for advanced storage technologies: Fibre
|
|
Channel, <acronym>SCSI</acronym>, software and hardware
|
|
RAID, <acronym>ATA</acronym> and
|
|
<acronym>SATA</acronym>.</simpara>
|
|
<simpara>FreeBSD supports a number of filesystems, and its
|
|
native UFS2 filesystem supports soft updates, snapshots and
|
|
very large filesystem sizes (16TB per filesystem)
|
|
<citation>McKu1999</citation>.</simpara>
|
|
<simpara>FreeBSD's in-kernel <acronym>GEOM</acronym> (&man.geom.4;)
|
|
framework allows kernel storage modules to be
|
|
composed in flexible ways.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>Over &os.numports; ported applications, both commercial
|
|
and open-source, managed via the FreeBSD ports
|
|
collection.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>Organizational Structure</title>
|
|
<para>FreeBSD's organizational structure is
|
|
non-hierarchical.</para>
|
|
|
|
<para>There are essentially two kinds of contributors to
|
|
FreeBSD, general users of FreeBSD, and developers with write
|
|
access (known as <firstterm>committers</firstterm> in the
|
|
jargon) to the source base.</para>
|
|
|
|
<para>There are many thousands of contributors in the first
|
|
group; the vast majority of contributions to FreeBSD come from
|
|
individuals in this group. Commit rights (write access) to
|
|
the repository are granted to individuals who contribute
|
|
consistently to the project. Commit rights come with
|
|
additional responsibilities, and new committers are assigned
|
|
mentors to help them learn the ropes.</para>
|
|
|
|
<figure>
|
|
<title>FreeBSD Organization</title>
|
|
<mediaobject>
|
|
<imageobject>
|
|
<imagedata fileref="freebsd-organization" format="PIC">
|
|
</imageobject>
|
|
</mediaobject>
|
|
</figure>
|
|
|
|
<para>Conflict resolution is performed by a nine member
|
|
<quote>Core Team</quote> that is elected from the group of
|
|
committers.</para>
|
|
|
|
<para>FreeBSD does not have <quote>corporate</quote> committers.
|
|
Individual committers are required to take responsibility for
|
|
the changes they introduce to the code. The <ulink
|
|
url="&url.articles.committers-guide;">FreeBSD Committer's
|
|
guide</ulink> <citation>ComGuide</citation> documents the
|
|
rules and responsibilities for committers.</para>
|
|
|
|
<para>FreeBSD's project model is examined in detail in
|
|
<citation>Nik2005</citation>.</para>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>FreeBSD Release Engineering Processes</title>
|
|
|
|
<para>FreeBSD's release engineering processes play a major role
|
|
in ensuring that its released versions are of a high quality.
|
|
At any point of time, FreeBSD's volunteers support multiple
|
|
code lines (<xref linkend="fig-freebsd-branches">):</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara>New features and disruptive code enters on the
|
|
development branch, also known as the
|
|
<firstterm>-CURRENT</firstterm> branch.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara><firstterm>-STABLE</firstterm> branches are code
|
|
lines that are branched from HEAD at regular intervals.
|
|
Only tested code is allowed onto a -STABLE branch. New
|
|
features are allowed once they have been tested and
|
|
stabilized in the -CURRENT branch.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara><firstterm>-RELEASE</firstterm> branches are
|
|
maintained by the FreeBSD security team. Only bug fixes
|
|
for critical issues are permitted onto -RELEASE
|
|
branches.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<figure id="fig-freebsd-branches">
|
|
<title>FreeBSD Release Branches</title>
|
|
<mediaobject>
|
|
<imageobject>
|
|
<imagedata fileref="freebsd-branches" format="EPS">
|
|
</imageobject>
|
|
</mediaobject>
|
|
</figure>
|
|
|
|
<para>Code lines are kept alive for as long as there is user and
|
|
developer interest in them.</para>
|
|
|
|
<para>Machine architectures are grouped into
|
|
<quote>tiers</quote>; <firstterm>Tier 1</firstterm>
|
|
architectures are fully supported by the project's release
|
|
engineering and security teams, <firstterm>Tier 2</firstterm>
|
|
architectures are supported on a best effort basis, and
|
|
experimental architectures comprise <firstterm>Tier
|
|
3</firstterm>. The list of <ulink
|
|
url="&url.articles.committers-guide;/archs.html">supported
|
|
architectures</ulink> is part of the FreeBSD documentation
|
|
collection.</para>
|
|
|
|
<para>The release engineering team publishes a <ulink
|
|
url="&url.base;/releng/">road map</ulink> for future
|
|
releases of FreeBSD on the project's web site. The dates laid
|
|
down in the road map are not deadlines; FreeBSD is released
|
|
when its code and documentation are ready.</para>
|
|
|
|
<para>FreeBSD's release engineering processes are described in
|
|
<citation>RelEngDoc</citation>.</para>
|
|
|
|
</sect2>
|
|
</sect1>
|
|
|
|
<sect1 id="freebsd-collaboration">
|
|
<title>Collaborating with FreeBSD</title>
|
|
|
|
<para>Open-source projects like FreeBSD offer finished code of a
|
|
very high quality <citation>Cov2005</citation>. Previous
|
|
studies have examined the effect of source code availability on
|
|
software development <citation>Com2004</citation>.</para>
|
|
|
|
<para>While access to quality source code can reduce the cost of
|
|
initial development, in the long-term the costs of managing
|
|
change begin to dominate. As computing environments change over
|
|
the years and new security vulnerabilities are discovered, your
|
|
product too needs to change and adapt. Using open-source code is
|
|
best viewed not as a one-off activity, but as an
|
|
<emphasis>ongoing process</emphasis>. The best projects to
|
|
collaborate with are the ones that are
|
|
<emphasis>live</emphasis>; i.e., with an active community, clear
|
|
goals and a transparent working style.</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<simpara>FreeBSD has an active developer community around it.
|
|
At the time of writing there are many thousands of
|
|
contributors from every populated continent in the world and
|
|
over 300 individuals with write access to the project's
|
|
source repositories.</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>The goals of the FreeBSD project are
|
|
<citation>Hub1994</citation>:
|
|
<itemizedlist spacing="compact">
|
|
<listitem>
|
|
<simpara>To develop a high-quality operating system for
|
|
popular computer hardware, and,</simpara>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>To make our work available to all under a liberal
|
|
license.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</listitem>
|
|
<listitem>
|
|
<simpara>FreeBSD enjoys an open and transparent working
|
|
culture. Nearly all discussion in the project happens by
|
|
email, on <ulink url="&a.mailman.listinfo;">public mailing
|
|
lists</ulink> that are also archived for posterity. The
|
|
project's policies are <ulink
|
|
url="&url.base;/internal/policies.html">documented</ulink>
|
|
and maintained under revision control. Participation in the
|
|
project is open to all.</simpara>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<sect2 id="freebsd-org">
|
|
<title>Understanding FreeBSD culture</title>
|
|
|
|
<para>To be able to work effectively with the FreeBSD project,
|
|
you need to understand the project's culture.</para>
|
|
|
|
<para>Volunteer driven projects operate under different rules
|
|
than for-profit corporates. A common mistake that companies
|
|
make when venturing into the open-source world is that of
|
|
underplaying these differences.</para>
|
|
|
|
<!-- XXX using <formalpara> constructs is clunky, but I like using
|
|
<variablelist> even less -->
|
|
<formalpara>
|
|
<title>Motivation</title>
|
|
|
|
<para>Most contributions to FreeBSD are done voluntarily
|
|
without monetary rewards entering the picture. The factors
|
|
that motivate individuals are complex, ranging from
|
|
altruism, to an interest in solving the kinds of problems
|
|
that FreeBSD attempts to solve. In this environment,
|
|
<quote>elegance is never optional</quote>
|
|
<citation>Nor1993</citation>.</para>
|
|
</formalpara>
|
|
|
|
<formalpara>
|
|
<title>The Long Term View</title>
|
|
<para>FreeBSD traces its roots back nearly twenty years to the
|
|
work of the Computer Science Research Group at the
|
|
University of California Berkeley.<footnote>
|
|
<simpara>FreeBSD's <ulink
|
|
url="http://cvsweb.freebsd.org/">source
|
|
repository</ulink> contains a history of the project
|
|
since its inception, and there are <ulink
|
|
url="http://www.mckusick.com/csrg/">CDROMs
|
|
available</ulink> that contain earlier code from the
|
|
CSRG.</simpara>
|
|
</footnote> A number of the original CSRG developers remain
|
|
associated with the project.</para>
|
|
</formalpara>
|
|
|
|
<para>The project values long-term perspectives
|
|
<citation>Nor2001</citation>. A frequent acronym encountered
|
|
in the project is <acronym>DTRT</acronym>, which stands for
|
|
<quote>Do The Right Thing</quote>.</para>
|
|
|
|
<formalpara>
|
|
<title>Development Processes</title>
|
|
<para>Computer programs are tools for communication: at one
|
|
level programmers communicate their intentions using a
|
|
precise notation to a tool (a compiler) that translates
|
|
their instructions to executable code. At another level,
|
|
the same notation is used for communication of intent
|
|
between two programmers.</para>
|
|
</formalpara>
|
|
|
|
<para>Formal specifications and design documents are seldom used
|
|
in the project. Clear and well-written code and well-written
|
|
change logs (<xref linkend="fig-change-log">) are used in
|
|
their place. FreeBSD development happens by <quote>rough
|
|
consensus and running code</quote>
|
|
<citation>Carp1996</citation>.</para>
|
|
|
|
<figure id="fig-change-log">
|
|
<title>A sample change log entry</title>
|
|
<programlisting>
|
|
bde 2005-10-29 16:34:50 UTC
|
|
|
|
FreeBSD src repository
|
|
|
|
Modified files:
|
|
lib/msun/src e_rem_pio2f.c
|
|
Log:
|
|
Use double precision to simplify and optimize arg reduction for small
|
|
and medium size args too: instead of conditionally subtracting a float
|
|
17+24, 17+17+24 or 17+17+17+24 bit approximation to pi/2, always
|
|
subtract a double 33+53 bit one. The float version is now closer to
|
|
the double version than to old versions of itself — it uses the same
|
|
33+53 bit approximation as the simplest cases in the double version,
|
|
and where the float version had to switch to the slow general case at
|
|
|x| == 2^7*pi/2, it now switches at |x| == 2^19*pi/2 the same as the
|
|
double version.
|
|
|
|
This speeds up arg reduction by a factor of 2 for |x| between 3*pi/4 and
|
|
2^7*pi/4, and by a factor of 7 for |x| between 2^7*pi/4 and 2^19*pi/4.
|
|
|
|
Revision Changes Path
|
|
1.14 +22 -97 src/lib/msun/src/e_rem_pio2f.c
|
|
</programlisting>
|
|
</figure>
|
|
|
|
<simpara>Communication between programmers is enhanced by the
|
|
use of a common coding standard &man.style.9;.</simpara>
|
|
|
|
<formalpara>
|
|
<title>Communication Channels</title>
|
|
<para>FreeBSD's contributors are spread across the world.
|
|
Email (and to a lesser extent, IRC) is the preferred means
|
|
of communication in the project.</para>
|
|
</formalpara>
|
|
</sect2>
|
|
|
|
<sect2>
|
|
<title>Best Practices for collaborating with the FreeBSD
|
|
project</title>
|
|
|
|
<para>We now look at a few best practices for making the best
|
|
use of FreeBSD in product development.</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>Plan for the long term</term>
|
|
<listitem>
|
|
<para>Setup processes that help in tracking the development of
|
|
FreeBSD. For example:</para>
|
|
<formalpara>
|
|
<title>Track FreeBSD source code</title>
|
|
<para>The project makes it easy to mirror its CVS
|
|
repository using <ulink
|
|
url="&url.articles.cvsup-advanced;"><!--
|
|
--><application>CVSup</application></ulink>. Having
|
|
the complete history of the source is useful when
|
|
debugging complex problems and offers valuable insight
|
|
into the intentions of the original developers. Use a
|
|
capable source control system that allows you to
|
|
easily merge changes between the upstream FreeBSD code
|
|
base and your own in-house code.</para>
|
|
</formalpara>
|
|
<para><xref linkend="fig-cvs-annotate"> shows a portion of
|
|
an annotated listing of the file referenced by the
|
|
change log in <xref linkend="fig-change-log">. The
|
|
ancestry of each line of the source is clearly visible.
|
|
Annotated listings showing the history of every file
|
|
that is part of FreeBSD are <ulink
|
|
url="http://cvsweb.freebsd.org/">available on the
|
|
web</ulink>.</para>
|
|
<figure id="fig-cvs-annotate">
|
|
<title>An annotated source listing generated using <command>cvs annotate</command></title>
|
|
<programlisting>
|
|
#LINE #REV #WHO #DATE #TEXT
|
|
|
|
62 1.1 (jkh 19-Aug-94): int32_t __ieee754_rem_pio2f(float x, float *y)
|
|
63 1.1 (jkh 19-Aug-94): {
|
|
64 1.14 (bde 29-Oct-05): double z,w,t,r,fn;
|
|
65 1.13 (bde 29-Oct-05): double tx[3];
|
|
66 1.14 (bde 29-Oct-05): int32_t e0,i,nx,n,ix,hx;
|
|
67 1.1 (jkh 19-Aug-94):
|
|
68 1.1 (jkh 19-Aug-94): GET_FLOAT_WORD(hx,x);
|
|
69 1.1 (jkh 19-Aug-94): ix = hx&0x7fffffff;
|
|
70 1.1 (jkh 19-Aug-94): if(ix<=0x3f490fd8) /* |x| ~<= pi/4 , no need for reduction */
|
|
71 1.1 (jkh 19-Aug-94): {y[0] = x; y[1] = 0; return 0;}
|
|
72 1.14 (bde 29-Oct-05): /* 33+53 bit pi is good enough for special and medium size cases */
|
|
73 1.2 (bde 07-Apr-95): if(ix<0x4016cbe4) { /* |x| < 3pi/4, special case with n=+-1 */
|
|
74 1.14 (bde 29-Oct-05): if(hx>0) {
|
|
75 1.15 (bde 06-Nov-05): z = x - pio2;
|
|
76 1.15 (bde 06-Nov-05): n = 1;
|
|
77 1.15 (bde 06-Nov-05): } else {
|
|
78 1.15 (bde 06-Nov-05): z = x + pio2;
|
|
79 1.15 (bde 06-Nov-05): n = 3;
|
|
80 1.9 (bde 08-Oct-05): }
|
|
81 1.15 (bde 06-Nov-05): y[0] = z;
|
|
82 1.15 (bde 06-Nov-05): y[1] = z - y[0];
|
|
83 1.15 (bde 06-Nov-05): return n;
|
|
84 1.15 (bde 06-Nov-05): }
|
|
85 1.15 (bde 06-Nov-05): if(ix<0x407b53d1) { /* |x| < 5*pi/4, special case with n=+-2 */
|
|
</programlisting>
|
|
</figure>
|
|
|
|
<formalpara>
|
|
<title>Use a gatekeeper</title>
|
|
<para>Appoint a <firstterm>gatekeeper</firstterm> to
|
|
monitor FreeBSD development, to keep an eye out for
|
|
changes that could potentially impact your
|
|
products.</para>
|
|
</formalpara>
|
|
<formalpara>
|
|
<title>Report bugs upstream</title>
|
|
<para>If you notice bug in the FreeBSD code that you are
|
|
using, file a <ulink url="&url.base;/send-pr.html">bug
|
|
report</ulink>. This step helps ensure that you do
|
|
not have to fix the bug the next time you take a code
|
|
drop from upstream.</para>
|
|
</formalpara>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>Leverage FreeBSD's release engineering efforts</term>
|
|
<listitem>
|
|
<simpara>Use code from a -STABLE development branch of
|
|
FreeBSD. These development branches are formally
|
|
supported by FreeBSD's release engineering and security
|
|
teams and comprise of tested code.
|
|
</simpara>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>Donate code to reduce costs</term>
|
|
<listitem>
|
|
<simpara>A major proportion of the costs associated with
|
|
developing products is that of doing maintenance. By
|
|
donating non-critical code to the project, you benefit
|
|
by having your code see much wider exposure than it
|
|
would otherwise get. This in turn leads to more bugs
|
|
and security vulnerabilities being flushed out and
|
|
performance anomalies being identified and fixed.
|
|
</simpara>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>Get support effectively</term>
|
|
<listitem>
|
|
<simpara>For products with tight deadlines, it is
|
|
recommended that you hire or enter into a consulting
|
|
agreement with a developer or firm with FreeBSD
|
|
experience. The &a.jobs; is a useful communication
|
|
channel to find talent. The FreeBSD project maintains a
|
|
<ulink
|
|
url="&url.base;/commercial/consult_bycat.html">gallery
|
|
of consultants and consulting firms</ulink>
|
|
undertaking FreeBSD work. The <ulink
|
|
url="http://www.bsdcertification.org/">BSD
|
|
Certification Group</ulink> offers certification for
|
|
all the major BSD derived OSes.</simpara>
|
|
|
|
<simpara>For less critical needs, you can ask for help on
|
|
the <ulink
|
|
url="http://lists.FreeBSD.org/mailman/listinfo">project
|
|
mailing lists</ulink>. A useful guide to follow when
|
|
asking for help is given in
|
|
<citation>Ray2004</citation>.
|
|
</simpara>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>Publicize your involvement</term>
|
|
<listitem>
|
|
<simpara>You are not required to publicize your use of
|
|
FreeBSD, but doing so helps both your effort as well as
|
|
that of the project.</simpara>
|
|
<simpara>Letting the FreeBSD community know that your
|
|
company uses FreeBSD helps improve your chances of
|
|
attracting high quality talent. A large roster of
|
|
support for FreeBSD also means more mind share for it
|
|
among developers. This in turn yields a healthier
|
|
foundation for your future.</simpara>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>Support FreeBSD developers</term>
|
|
<listitem>
|
|
<simpara>Sometimes the most direct way to get a desired
|
|
feature into FreeBSD is to support a developer who is
|
|
already looking at a related problem. Help can range
|
|
from hardware donations to direct financial assistance.
|
|
In some countries, donations to the FreeBSD project
|
|
enjoy tax benefits. The project has a dedicated <ulink
|
|
url="&url.base;/donations/">donations liaison</ulink>
|
|
to assist donors. The project also maintains a web page
|
|
where developers <ulink
|
|
url="&url.base;/donations/wantlist.html">list their
|
|
needs</ulink>.
|
|
</simpara>
|
|
<simpara>As a policy the FreeBSD project <ulink
|
|
url="&url.articles.contributors;">acknowledges</ulink>
|
|
all contributions received on its web site.</simpara>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</sect2>
|
|
</sect1>
|
|
|
|
<sect1 id="conclusion">
|
|
<title>Conclusion</title>
|
|
<para>The FreeBSD project's goals are to create and give away the
|
|
source code for a high-quality operating system. By working
|
|
with the FreeBSD project you can reduce development costs and
|
|
improve your time to market in a number of product development
|
|
scenarios.</para>
|
|
<para>We examined the characteristics of the FreeBSD project that
|
|
make it an excellent choice for being part of an organization's
|
|
product strategy. We then looked at the prevailing culture of
|
|
the project and examined effective ways of interacting with its
|
|
developers. The article concluded with a list of best-practices
|
|
that could help organizations collaborating with the
|
|
project.</para>
|
|
</sect1>
|
|
|
|
<bibliography>
|
|
<biblioentry>
|
|
<abbrev>Carp1996</abbrev>
|
|
<citetitle><ulink url="http://www.ietf.org/rfc/rfc1958.txt">The
|
|
Architectural Principles of the Internet</ulink></citetitle>
|
|
<author>
|
|
<firstname>B.</firstname>
|
|
<surname>Carpenter</surname>
|
|
<affiliation>
|
|
<orgname>The Internet Architecture Board</orgname>
|
|
</affiliation>
|
|
</author>
|
|
<copyright>
|
|
<year>1996</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry xreflabel="Com2004">
|
|
<abbrev>Com2004</abbrev>
|
|
<citetitle><ulink
|
|
url="http://csdl.computer.org/comp/mags/so/2004/01/s1028.pdf">How
|
|
is Open-Source Affecting Software
|
|
Development?</ulink></citetitle>
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Diomidis</firstname>
|
|
<surname>Spinellis</surname>
|
|
</author>
|
|
<author>
|
|
<firstname>Clemens</firstname>
|
|
<surname>Szyperski</surname>
|
|
</author>
|
|
</authorgroup>
|
|
<title>IEEE Computer</title>
|
|
<copyright>
|
|
<year>Jan/Feb 2004</year>
|
|
</copyright>
|
|
<publisher>
|
|
<publishername>IEEE Computer Society</publishername>
|
|
</publisher>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>ComGuide</abbrev>
|
|
<citetitle><ulink
|
|
url="&url.articles.committers-guide;">Committer's
|
|
Guide</ulink></citetitle>
|
|
<authorgroup>
|
|
<corpauthor>The FreeBSD Project</corpauthor>
|
|
</authorgroup>
|
|
<copyright>
|
|
<year>2005</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>Cov2005</abbrev>
|
|
<citetitle><ulink
|
|
url="http://www.coverity.com/news/nf_news_06_27_05_story_9.html">Coverity
|
|
study on kernel security holes in Linux and FreeBSD</ulink></citetitle>
|
|
<authorgroup>
|
|
<corpauthor>Coverity Inc.</corpauthor>
|
|
</authorgroup>
|
|
<copyright>
|
|
<year>2005</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>GoldGab2005</abbrev> <citetitle><ulink
|
|
url="http://dreamsongs.com/IHE/IHE.html">Innovation Happens
|
|
Elsewhere: Open Source as Business Strategy</ulink></citetitle>
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Ron</firstname>
|
|
<surname>Goldman</surname>
|
|
</author>
|
|
<author>
|
|
<firstname>Richard</firstname>
|
|
<surname>Gabriel</surname>
|
|
</author>
|
|
</authorgroup>
|
|
<copyright>
|
|
<year>2005</year>
|
|
</copyright>
|
|
<isbn>ISBN 1558608893</isbn>
|
|
<publisher>
|
|
<publishername>Morgan-Kaufmann</publishername>
|
|
</publisher>
|
|
</biblioentry>
|
|
<biblioentry xreflabel="Hub1994">
|
|
<!-- XXX Get the date of this article right -->
|
|
<abbrev>Hub1994</abbrev>
|
|
<citetitle><ulink url="&url.articles.contributing;">Contributing
|
|
to the FreeBSD Project</ulink></citetitle>
|
|
<author>
|
|
<firstname>Jordan</firstname>
|
|
<surname>Hubbard</surname>
|
|
</author>
|
|
<copyright>
|
|
<year>1994—2005</year>
|
|
</copyright>
|
|
<publisher>
|
|
<publishername>The FreeBSD Project</publishername>
|
|
</publisher>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>McKu1999</abbrev>
|
|
<citetitle><ulink
|
|
url="http://www.usenix.org/publications/library/proceedings/usenix99/mckusick.html">Soft
|
|
Updates: A Technique for Eliminating Most Synchronous Writes
|
|
in the Fast Filesystem</ulink></citetitle>
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Kirk</firstname>
|
|
<surname>McKusick</surname>
|
|
</author>
|
|
<author>
|
|
<firstname>Gregory</firstname>
|
|
<surname>Ganger</surname>
|
|
</author>
|
|
</authorgroup>
|
|
<confgroup>
|
|
<conftitle>USENIX Annual Technical Conference</conftitle>
|
|
</confgroup>
|
|
<copyright>
|
|
<year>1999</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>McKu1999-1</abbrev>
|
|
<citetitle><ulink
|
|
url="http://www.oreilly.com/catalog/opensources/book/kirkmck.html"
|
|
>Twenty Years of Berkeley Unix: From AT&T-Owned to
|
|
Freely Redistributable</ulink></citetitle>
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Marshall Kirk</firstname>
|
|
<surname>McKusick</surname>
|
|
</author>
|
|
</authorgroup>
|
|
<title><ulink
|
|
url="http://www.oreilly.com/catalog/opensources/book/toc.html">Open
|
|
Sources: Voices from the Open Source
|
|
Revolution</ulink></title>
|
|
<isbn>ISBN 1-56592-582-3</isbn>
|
|
<publisher>
|
|
<publishername>O'Reilly Inc.</publishername>
|
|
</publisher>
|
|
<copyright>
|
|
<year>1993</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>Mon2005</abbrev>
|
|
<citetitle><ulink url="&url.articles.bsdl-gpl;/article.html">Why you should
|
|
use a BSD style license for your Open Source
|
|
Project</ulink></citetitle>
|
|
<author>
|
|
<firstname>Bruce</firstname>
|
|
<surname>Montague</surname>
|
|
</author>
|
|
<publisher>
|
|
<publishername>The FreeBSD Project</publishername>
|
|
</publisher>
|
|
<copyright>
|
|
<year>2005</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry xreflabel="Nik2005">
|
|
<abbrev>Nik2005</abbrev>
|
|
<citetitle><ulink url="&url.books.dev-model;/book.html">A
|
|
project model for the FreeBSD Project</ulink></citetitle>
|
|
<author>
|
|
<firstname>Niklas</firstname>
|
|
<surname>Saers</surname>
|
|
</author>
|
|
<copyright>
|
|
<year>2005</year>
|
|
</copyright>
|
|
<publisher>
|
|
<publishername>The FreeBSD Project</publishername>
|
|
</publisher>
|
|
</biblioentry>
|
|
<biblioentry xreflabel="Nor1993">
|
|
<abbrev>Nor1993</abbrev>
|
|
<citetitle><ulink
|
|
url="http://www.norvig.com/luv-slides.ps">Tutorial
|
|
on Good Lisp Programming Style</ulink></citetitle>
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Peter</firstname>
|
|
<surname>Norvig</surname>
|
|
</author>
|
|
<author>
|
|
<firstname>Kent</firstname>
|
|
<surname>Pitman</surname>
|
|
</author>
|
|
</authorgroup>
|
|
<copyright>
|
|
<year>1993</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>Nor2001</abbrev>
|
|
<citetitle><ulink url="http://www.norvig.com/21-days.html">Teach
|
|
Yourself Programming in Ten Years</ulink></citetitle>
|
|
<author>
|
|
<firstname>Peter</firstname>
|
|
<surname>Norvig</surname>
|
|
</author>
|
|
<copyright>
|
|
<year>2001</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>Ray2004</abbrev>
|
|
<citetitle><ulink
|
|
url="http://www.catb.org/~esr/faqs/smart-questions.html">How
|
|
to ask questions the smart way</ulink></citetitle>
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Eric Steven</firstname>
|
|
<surname>Raymond</surname>
|
|
</author>
|
|
</authorgroup>
|
|
<copyright>
|
|
<year>2004</year>
|
|
</copyright>
|
|
</biblioentry>
|
|
<biblioentry>
|
|
<abbrev>RelEngDoc</abbrev>
|
|
<citetitle><ulink url="&url.articles.releng;">FreeBSD Release
|
|
Engineering</ulink></citetitle>
|
|
<author>
|
|
<firstname>Murray</firstname>
|
|
<surname>Stokely</surname>
|
|
</author>
|
|
<copyright>
|
|
<year>2001</year>
|
|
</copyright>
|
|
<publisher>
|
|
<publishername>The FreeBSD Project</publishername>
|
|
</publisher>
|
|
</biblioentry>
|
|
</bibliography>
|
|
|
|
</article>
|