busybox

Building a Busybox Boot Floppy

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This document describes how to buid a boot floppy using the following

components:

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 - Linux Kernel (http://www.kernel.org)

 - uClibc: C library (http://cvs.uclinux.org/uClibc.html)

 - Busybox: Unix utilities (http://busybox.lineo.com)

 - Syslinux: bootloader (http://syslinux.zytor.com)

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It is based heavily on a paper presented by Erik Andersen at the 2001 Embedded

Systems Conference.

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Building The Software Components

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Detailed instructions on how to build Busybox, uClibc, or a working Linux

kernel are beyond the scope of this document. The following guidelines will

help though:

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    - Stock Busybox from CVS or a tarball will work with no modifications to

      any files. Just extract and go.

    - Ditto uClibc.

    - Your Linux kernel must include support for initrd or else the floppy

      won't be able to mount it's root file system.

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If you require further information on building Busybox uClibc or Linux, please

refer to the web pages and documentation for those individual programs.

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Making a Root File System

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The following steps will create a root file system.

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 - Create an empty file that you can format as a filesystem:

    dd if=/dev/zero of=rootfs bs=1k count=4000

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 - Set up the rootfs file we just created to be used as a loop device (may not

   be necessary) 

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    losetup /dev/loop0 rootfs 

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 - Format the rootfs file with a filesystem:

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    mkfs.ext2 -F -i 2000 rootfs

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 - Mount the file on a mountpoint so we can place files in it:

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    mkdir loop

    mount -o loop rootfs loop/

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    (you will probably need to be root to do this)

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 - Copy on the C library, the dynamic linking library, and other necessary

   libraries. For this example, we copy the following files from the uClibc

   tree:

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