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Abstract
This document provides information about the NanoBSD tools, which can be used to create FreeBSD system images for embedded applications, suitable for use on a USB key, memory card or other mass storage media.
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NanoBSD is a tool developed by {phk} and now maintained by {imp}. It creates a FreeBSD system image for embedded applications, suitable for use on a USB key, memory card or other mass storage media.
It can be used to build specialized install images, designed for easy installation and maintenance of systems commonly called "computer appliances". Computer appliances have their hardware and software bundled in the product, which means all applications are pre-installed. The appliance is plugged into an existing network and can begin working (almost) immediately. Den kan brukes til å lage spesialiserte installasjonsbilder, designet for enkel installasjon og vedlikehold av systemer som ofte kalles <quote>datamaskinapparater</quote>. Datamaskiner er utstyrt med maskinvaren og programvaren i produktet, noe som betyr at alle applikasjoner er forhåndsinstallert. Apparatet er koblet til et eksisterende nettverk og kan begynne å fungere (nesten) umiddelbart.
The features of NanoBSD include:
Ports and packages work as in FreeBSD - Every single application can be installed and used in a NanoBSD image, the same way as in FreeBSD. Porter og pakker fungerer som i FreeBSD - Hvert enkelt program kan installeres og brukes i et <application>NanoBSD</application>-bilde, på samme måte som i FreeBSD.
No missing functionality - If it is possible to do something with FreeBSD, it is possible to do the same thing with NanoBSD, unless the specific feature or features were explicitly removed from the NanoBSD image when it was created.
Everything is read-only at run-time - It is safe to pull the power-plug. There is no necessity to run man:fsck[8] after a non-graceful shutdown of the system.
Easy to build and customize - Making use of just one shell script and one configuration file it is possible to build reduced and customized images satisfying any arbitrary set of requirements. Lett å bygge og tilpasse - Ved å bruke bare ett skallskript og en konfigurasjonsfil er det mulig å lage reduserte og tilpassede bilder som tilfredsstiller ethvert vilkårlig sett med krav.
Once the image is present on the medium, it is possible to boot NanoBSD. The mass storage medium is divided into three parts by default:
Two image partitions: `code#1` and `code#2`.
The configuration file partition, which can be mounted under the [.filename]#/cfg# directory at run time. Konfigurasjonsfilpartisjonen, som kan monteres under katalogen <filename>/cfg</filename> på kjøretid.
The [.filename]#/etc# and [.filename]#/var# directories are man:md[4] (malloc) disks.
The configuration file partition persists under the [.filename]#/cfg# directory. It contains files for [.filename]#/etc# directory and is briefly mounted read-only right after the system boot, therefore it is required to copy modified files from [.filename]#/etc# back to the [.filename]#/cfg# directory if changes are expected to persist after the system restarts.
Making Persistent Changes to [.filename]#/etc/resolv.conf#
# vi /etc/resolv.conf
[...]
# mount /cfg
# cp /etc/resolv.conf /cfg
# umount /cfg
The partition containing [.filename]#/cfg# should be mounted only at boot time and while overriding the configuration files. Partisjonen som inneholder <filename>/cfg</filename> skal bare monteres ved starttid og samtidig overstyre konfigurasjonsfilene.
Keeping [.filename]#/cfg# mounted at all times is not a good idea, especially if the NanoBSD system runs off a mass storage medium that may be adversely affected by a large number of writes to the partition (like when the filesystem syncer flushes data to the system disks). Å holde <filename>/cfg</filename> montert til enhver tid er ikke en god idé, spesielt hvis <application>NanoBSD</application>-systemet kjører av et masselagringsmedium som kan påvirkes negativt av et stort antall skriver til partisjonen (som når filsystemssynkronen skyller data til systemets disker).
A NanoBSD image is built using a simple [.filename]#nanobsd.sh# shell script, which can be found in the [.filename]#/usr/src/tools/tools/nanobsd# directory. This script creates an image, which can be copied on the storage medium using the man:dd[1] utility.