It is possible to install NetBSD together with other operating systems on one hard disk.

If there is already something on the hard disk, think how you can free some space for NetBSD; if NetBSD will share the disk with other operating systems you will probably need to create a new partition (which you will do with sysinst) and, maybe, to resize an existing one.

It is not possible to resize an existing partition with sysinst, but there are some commercial products (like Partition Magic) and some free tools (FIPS, pfdisk) available for this.

You can also install NetBSD on a separate hard disk.

With modern and powerful hardware it is possible to install and run NetBSD on top of other operating systems - without the cumbersomeness of dual booting. Emulators or virtualization environments provide a fast and secure way to try out NetBSD. The host operating system stays unchanged, and the risk to damage important data is limited.

This requires the correct setup of an emulation software or virtualization technology on the hosting operating system. That given, it is just at matter of creating a file-based image and using an install CD image to start with NetBSD.

Information about NetBSD as a Xen host and guest system is available on the NetBSD/xen web page

The NetBSD on emulated hardware web page provides detailed information about various emulators and the supported NetBSD platforms

The first thing to do before installing NetBSD is to read the release information and installation notes in one of the INSTALL.* files: this is the official description of the installation procedure, with platform specific information and important details. It can be found in the root directory of the NetBSD release (on the install CD or on the FTP server):

It is advisable to print the INSTALL.* document out. It is available in various formats, usually .txt, .ps, .more and .html

It is sensible to be aware of geometry issues that may arise in relation to the used hard disk. First of all, you should know about sector size. You can count on this to be 512 bytes; other sizes are rare (and currently not supported). Of particular interest are the number of sectors per track, the number of tracks per cylinder (also known as the number of heads), and the number of cylinders. Together they describe the disk geometry.

The BIOS has a limit of 1024 cylinders and 63 sectors per track for doing BIOS I/O. This is because of the old programming interface to the BIOS that restricts these values. Most of the big disks currently being used have more than 1024 real cylinders. Some have more than 63 sectors per track. Therefore, the BIOS can be instructed to use a fake geometry that accesses most of the disk and the fake geometry has less than or equal to 1024 cylinders and less than or equal to 63 sectors. This is possible because the disks can be addressed in a way that is not restricted to these values, and the BIOS can internally perform a translation. This can be activated in most modern BIOSes by using Large or LBA mode for the disk.

NetBSD does not have the mentioned limitations with regard to the geometry. However, since the BIOS has to be used during startup, it is important to know about the geometry the BIOS uses. The NetBSD kernel should be on a part of the disk where it can be loaded using the BIOS, within the limitations of the BIOS geometry. The install program will check this for you, and will give you a chance to correct this if this is not the case.

If you have not yet installed any other systems on the hard disk that you plan to install NetBSD on, or if you plan to use the disk entirely for NetBSD, you may wish to check your BIOS settings for the `Large' or `LBA' modes, and activate them for the hard disk in question. While they are not needed by NetBSD as such, doing so will remove the limitations mentioned above, and will avoid hassle should you wish to share the disk with other systems. Do not change these settings if you already have data on the disk that you want to preserve!

In any case, it is wise to check the BIOS settings for the hard disk geometry before beginning the installation, and write them down. While this should usually not be needed, it enables you to verify that the install program determines these values correctly.

The geometry that the BIOS uses will be referred to as the BIOS geometry, the geometry that NetBSD uses is the real geometry.

sysinst, the NetBSD installation program, will try to discover both the real geometry and BIOS geometry.

It is important that sysinst know the proper BIOS geometry to be able to get NetBSD to boot, regardless of where on your disk you put it. It is less of a concern if the disk is going to be used entirely for NetBSD. If you intend to have several OSes on your disk, this becomes a much larger issue.

The installation program mentions two types of hard disk geometries:

real geometry is the real geometry of the hard disk, detected by the system. BIOS geometry is the geometry used by the BIOS and it could be different from the real one (for example, BIOS could remap the disk using LBA).

The disk used in the installation example is an IDE disk with the following geometries:

real:  6232 cyl,   16 heads,  63 sec
BIOS:   779 cyl,  128 heads,  63 sec   (LBA)

As you can see the BIOS remaps the disk using LBA, effectively reducing the number of cylinders and increasing the number of tracks (but the result is the same: 6232 * 16 = 779 * 128 = 99712). A sector contains 512 bytes, which means that the disk size is 6232 * 16 * 63 * 512 = 3 GB. NetBSD does not need to remap the disk geometry (and in fact won't do it). During the installation it is possible to change manually the geometry if sysinst got it wrong.

The terminology used by NetBSD for partitioning is different from the typical DOS/Windows terminology; in fact, there are two partitioning schemes. NetBSD installs in one of the four primary BIOS partitions (the partitions defined in the hard disk partition table).

Within a BIOS partition (also called slice) NetBSD defines its BSD partitions using a disklabel: these partitions can be seen only by NetBSD and are identified by lowercase letters (starting with “a”). For example, wd0a refers to the “a” partition of the first IDE disk (wd0) and sd0a refers to the “a” partition of the first SCSI disk. In Figure 2.1, “Partitions” there are two primary BIOS partitions, one used by DOS and the other by NetBSD. NetBSD describes the disk layout through the disklabel.

Figure 2.1. Partitions

A fresh installed NetBSD system will take about 360 MB of disk space. Additional disk space will be needed for a swap partition, applications and for the users data.

Write down the basic network settings. Especially if you plan to install over network via FTP or NFS you will need:

Before you begin the installation, make sure that you have a reliable backup of any operating systems and data on the used hard disk. Mistakes in partitioning your hard disk may lead to data loss. Already installed operating systems may become unbootable. "Reliable backup" means that the backup and restore procedure is tested to work faultless!

The NetBSD installsystem consists of two parts. The first part is the installation kernel. This kernel contains the NetBSD install program sysinst and it needs to get booted from a CD (or DVD), Memory card, USB flash drive or from a floppy disk. The sysinst program will prepare the disk: it separates the disk space into partitions, makes the disk bootable and creates the necessary file systems.

The second part of the install system are the binary distribution sets, the files of the NetBSD operating system. The installer needs to have access to the distribution sets. sysinst can reach them via network (NFS server), internet (FTP server), on CDs/DVDs or on disks (with file systems that are supported by the installation kernel).

On big disks like CDs or memory cards, the install kernel and distribution sets can be stored together. The NetBSD Project provides those complete install media for every supported hardware architecture. They are available as bootable CD images (*.iso and *.iso.torrent files):

# cd i386/installation/floppy
      # dd if=boot.fs of=/dev/fd0a bs=36b

grub>
grub> find /data/netbsd-INSTALL
    (hd1,0)

grub> root (hd1,0)
      Filesystem type is fat, partition type 0xb

grub> kernel --type=netbsd /data/netbsd-INSTALL

grub> boot
...