Chapter 34. Building NetBSD installation media

Table of Contents

34.1. Creating custom install or boot floppies for your architecture e.g. i386
34.2. Creating a custom install or boot CD with

34.1. Creating custom install or boot floppies for your architecture e.g. i386

Sometimes you may want to create your own boot or install floppies for i386 instead of using the precompiled ones, or tailor the ones built by the NetBSD build system. This section outlines the steps to do so.

The overall idea is to have a filesystem with some tools (sysinst, ls, whatever), and embed this filesystem as some sort of ramdisk into a NetBSD kernel. The kernel needs to include the md pseudo device to be able to hold a ramdisk. The kernel with the ramdisk can then be put on removable media or made available via the net (using NFS or TFTP).

To perform the following steps, you need to be running a kernel with the vnd pseudo device enabled (this is the default for a GENERIC kernel).

  1. First, you must create a valid kernel to put on your floppies, e.g. INSTALL. This kernel must include the md pseudo device, which allows embedding a ramdisk. See Chapter 32, Compiling the kernel for kernel building instructions.

  2. The next step is to create the ramdisk that gets embedded into the kernel. The ramdisk contains a filesystem with whatever tools are needed, usually init(8) and some tools like sysinst, ls(1), etc. To create the standard ramdisk, run make in the src/distrib/i386/ramdisks/ramdisk-big directory (for NetBSD 3.x: src/distrib/i386/floppies/ramdisk-big).

    This will create the ramdisk.fs file in the directory. If you want to customize the contents of the filesystem, customize the list file.

  3. Now, the ramdisk gets inserted into the kernel, producing a new kernel which includes the ramdisk, all in one file. To do so, change into the src/distrib/i386/instkernel directory (for NetBSD 3.x: src/distrib/i386/floppies/instkernel) and run make.

  4. The next step is to make one or more floppy images, depending on the size of the kernel (including the ramdisk). This is done by changing into /usr/src/distrib/i386/floppies/bootfloppy-big, and running make again.

    This will create one or two (depending on the size of kernel) files named boot1.fs and boot2.fs

  5. Last, transfer these files to the floppies with the commands

    # dd if=boot1.fs of=/dev/fd0a bs=36b
    # dd if=boot2.fs of=/dev/fd0a bs=36b
  6. Put the first floppy in the drive and power on!

34.2. Creating a custom install or boot CD with

Creating custom install or boot CDs is easy with The NetBSD base system includes the makefs tool for creating filesystems. This tool is used to create iso-images. Creating iso-images includes these tasks:

  1. Release build

    #./ release
  2. CD-ROM iso-image build

    #./ iso-image

The iso-image command will build a CD-ROM image in RELEASEDIR/MACHINE/installation


For now not all architectures are supported. The mac/68k ports doesn't boot for now.