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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/manual/bugs.xml | 28 | ||||
| -rw-r--r-- | doc/manual/introduction.xml | 77 |
2 files changed, 79 insertions, 26 deletions
diff --git a/doc/manual/bugs.xml b/doc/manual/bugs.xml index eb479945ab..4d5017e440 100644 --- a/doc/manual/bugs.xml +++ b/doc/manual/bugs.xml @@ -1,7 +1,6 @@ -<appendix> - <title>Bugs / To-Do</title> +<appendix><title>Bugs / To-Do</title> - <itemizedlist> +<itemizedlist> <listitem> <para> @@ -99,17 +98,18 @@ $ nix-store -r $(cat /nix/var/nix/roots/bla)</screen> </para> </listitem> - <listitem> - <para> - For security, <command>nix-push</command> manifests should be - digitally signed, and <command>nix-pull</command> should - verify the signatures. The actual NAR archives in the cache - do not need to be signed, since the manifest contains - cryptographic hashes of these files (and - <filename>fetchurl.nix</filename> checks them). - </para> - </listitem> +<listitem><para>For security, <command>nix-push</command> manifests +should be digitally signed, and <command>nix-pull</command> should +verify the signatures. The actual NAR archives in the cache do not +need to be signed, since the manifest contains cryptographic hashes of +these files (and <filename>fetchurl.nix</filename> checks +them).</para></listitem> + +<listitem><para>We should switch away from MD5, since it has been +cracked. We don't currently depend very much on the +collision-resistance of MD5, but we will once we start sharing build +results between users.</para></listitem> - </itemizedlist> +</itemizedlist> </appendix> diff --git a/doc/manual/introduction.xml b/doc/manual/introduction.xml index 02a4383361..51804eb9b6 100644 --- a/doc/manual/introduction.xml +++ b/doc/manual/introduction.xml @@ -1,17 +1,70 @@ -<chapter> - <title>Introduction</title> +<chapter><title>Introduction</title> - <epigraph> - <para><quote>The number of Nix installations in the world has grown to 5, - with more expected.</quote></para> - </epigraph> +<epigraph><para><quote>The number of Nix installations in the world +has grown to 5, with more expected.</quote></para></epigraph> - <para> - Nix is a system for software deployment. It supports the - creation and distribution of software packages, as well as the installation - and subsequent management of these on target machines (i.e., it is also a - package manager). - </para> +<para>Nix is a system for the deployment of software. Software +deployment is concerned with the creation, distribution, and +management of software components (<quote>packages</quote>). There +are many tools for this, but they tend to ignore some important +requirements for deployment: + +<itemizedlist> + +<listitem><para><emphasis>Correctness</emphasis>. The basic goal of +software deployment is to transfer software from one machine (e.g., +the developer's, where it presumably works) to another machine (e.g., +the end user's). The software should work exactly the same on the +target machine as on the source machine. But this in practice turns +out to be rather difficult due to <emphasis>dependencies between +components</emphasis> and <emphasis>interference between +components</emphasis>. If we deploy a component that depends on other +components, then we should deploy those dependencies as well. If they +are missing on the target system, the component probably won't work. +If they <emphasis>are</emphasis> present but are not the right +version, the component might not work. And if even if they are the +right version, they may have been built with different flags or +options, which can cause incompatibilities. Interference occurs when +components <quote>collide</quote> with each other in the file system. +For instance, different versions of the same package tend to overwrite +each other, so they cannot be installed at the same time. But always +picking the latest version might break components that only work with +some older version.</para></listitem> + +<listitem><para><emphasis>Variability</emphasis>. Many package +management tools have difficulty supporting the installation of +multiple versions or variants of the same component. This is bad +because as ...</para></listitem> + +</itemizedlist> + +</para> + +<para>Here are some of Nix's main features: + +<itemizedlist> + +<listitem><para>Nix can quite reliably figure out the dependencies +between components.</para></listitem> + +</itemizedlist> + +</para> + +<warning><para>This manual is a work in progress. It's quite likely +to be incomplete, inconsistent with the current implementation, or +simply wrong.</para></warning> + +<note><para>Some background information on Nix can be found in two +papers. The ICSE 2004 paper <ulink +url='http://www.cs.uu.nl/~eelco/pubs/immdsd-icse2004-final.pdf'><citetitle>Imposing +a Memory Management Discipline on Software +Deployment</citetitle></ulink> discusses the hashing mechanism used to +ensure reliable dependency identification and non-interference between +different versions and variants of packages. The LISA 2004 paper +<citetitle>Nix: A Safe and Policy-Free System for Software +Deployment</citetitle> gives a more general discussion of Nix from a +system-administration perspective.</para></note> <para> Nix solves some large problems that exist in most current deployment and |