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3 - Getting started with OpenBSD

Table of Contents

• 3.1 - Buying an OpenBSD CD set
• 3.2 - Buying OpenBSD T-Shirts
• 3.3 - Does OpenBSD provide an ISO image for download?
• 3.4 - Downloading via HTTP, FTP, RSYNC or AFS
• 3.5 - Verifying your download
• 3.6 - Selecting Hardware
• 3.7 - What is an appropriate "first system" to learn OpenBSD on?

3.1 - Buying an OpenBSD CD set

Purchasing an OpenBSD CD set is generally the best way to get started. Visit the ordering page to purchase your copy: OpenBSD ordering page.

There are many good reasons to own an OpenBSD CD set:

• CD sales support ongoing development of OpenBSD.
• Development of a multi-platform operating system requires constant investment in equipment.
• Your support in the form of a CD set purchase has a real impact on future development.
• The CDs contains binaries (and source) for the most popular supported platforms.
• The CDs are bootable on several platforms, and can be used to bootstrap a machine without a pre-existing installed operating system.
• The CDs are useful for bootstrapping even if you choose to install a snapshot.
• Installing from CD is faster! Installing from CD preserves network connectivity resources.
• OpenBSD CDs always come with very nice stickers. Your system isn't fully complete without these. You can only get these stickers by buying a CD set or donating hardware.
• The CD set is complete enough to bring up a full development environment without any network connection at all.

If you're installing a release version of OpenBSD, you should use a official CD set.

3.2 - Buying OpenBSD T-Shirts

Yes, OpenBSD has T-shirts for your wearing enjoyment. You can view these at the OpenBSD T-shirts page. Enjoy :)

3.3 - Does OpenBSD provide an ISO image for download?

Most platforms that are able to boot from CD-ROM have ISO images available for download which can be used to create bootable OpenBSD install CD-ROMs. Both "full install" (all files needed for a full OpenBSD install, named install54.iso) and "boot only" (for installing from a network file source, named cd54.iso) ISOs are provided for these platforms.

Note, these ISO files are not the same as the official CD set. These images are for single platforms, and do not include any of the pre-compiled packages, stickers, or artwork that the official CD set does.

However, ISO file installation is NOT the optimum installation method for many people. It is still usually faster and simpler to download the boot media and then install just the portions needed. However, for those who wish to do a number of installations, or can not figure out how to drop ten files on a CD-ROM or set up a local HTTP/FTP server, ISOs are available.

The OpenBSD project does not make the ISO images used to master the official CDs available for download. The reason is simply that we would like you to buy the CD sets to help fund ongoing OpenBSD development. The official OpenBSD CD-ROM layout is copyright Theo de Raadt. Theo does not permit people to redistribute images of the official OpenBSD CDs. As an incentive for people to buy the CD set, some extras are included in the package as well (artwork, stickers etc).

Note that only the CD layout is copyrighted, OpenBSD itself is free. Nothing precludes someone else from downloading OpenBSD and making their own CD.

For those that need a bootable CD for their system, bootdisk ISO images (named cd54.iso) are available for a number of platforms which will then permit the rest of the system to be installed via HTTP/FTP. These ISO images are only a few megabytes in size, and contain just the installation tools, not the actual file sets.

3.4 - Downloading via HTTP, FTP, RSYNC or AFS

There are numerous international mirror sites offering HTTP and FTP access to OpenBSD releases and snapshots. RSYNC and AFS access are also available. You should always use the site nearest to you. Before you begin fetching a release or snapshot, you may wish to use ping(8) and traceroute(8) to determine which mirror site is nearest to you and whether that mirror is performing adequately. Of course, your OpenBSD release CD is always closer than any mirror. Access information is here:

OpenBSD Download page.

3.5 - Verifying your download

In the same directory as the installation sets, each mirror includes a file named SHA256 which contains checksums of the various installation files. You can confirm that none of the downloaded files were mangled in transit using the sha256(1) command:

$ sha256 -c SHA256

The OpenBSD project does not digitally sign releases. The above command only detects accidental damage, not malicious tampering. If the men in black suits are out to get you, they're going to get you.

3.6 - Selecting Hardware

Selecting appropriate hardware to run your OpenBSD system on is important, as it can mean the difference between success and failure of a project.

If you are shopping for a new PC, whether you are buying it piece by piece or completely pre-built, you want to make sure first that you are buying reliable parts. In the PC world, this is not easy. Bad or otherwise unreliable or mismatched parts can make OpenBSD run poorly and crash often. The best advice we can give is to be careful, and buy brands and parts that have been reviewed by an authority you trust. Sometimes, a higher-price machine is a better quality machine. Other times, it is simply more expensive.

There are certain things that will help bring out the maximum performance of your system:

• Let the application choose the hardware: It is usually better to make an adjustment to the hardware you were planning on using rather than compromising on your application design because you have something you "really wanted to use".
• Identify your bottlenecks: Don't pay extra for the cutting-edge processor if your application is restricted by disk I/O. Don't pay for fast disk if your system is restricted by network speed. Don't pay for much of anything if your bottleneck is a 128kbps DSL line.
• Keep it simple: Simple hardware usually has simple problems. Complex hardware that isn't supposed to ever break may take you a long time to repair when it breaks anyway.
• Use hardware you understand, or learn the new hardware before you implement a production system: Regardless of the technical merits of the hardware, committing to use a particular type of hardware before you have become familiar with it, both how it works and how it fails, is foolish.
• Use multiple disks: Instead of buying one large disk, buy multiple smaller disks. While this may cost more, distributing the load over multiple spindles will decrease the amount of time necessary to access data on the disks. And, with more spindles, you can get more reliability and faster data access with RAID.
• Break up large blocks of storage: Many people make the mistake of designing a system that stores large amounts of data to have one Big Block of Storage. This is usually a bad design. You will usually find it much better to break up your storage into manageable blocks. This has many advantages, two of the biggest being that you can add more storage later when you need it easily (you weren't going to get the requirements estimate right, no one ever does), and you can buy a small amount of storage now, and add much more later when the price will have most likely dropped and the capacity will have increased.
• Avoid cheap network adapters: OpenBSD supports a plethora of cheap network adapters. These adapters work great in home systems, and low or moderate throughput business and research environments. But, if you need high throughput and low impact on your server, you are better off buying a quality network adapter. Unfortunately, some name-brand adapters are not much better than the cheap adapters, and some potentially good adapters do not have accurate documentation available to write good drivers. Gigabit adapters often perform better than 10Mbps/100Mbps adapters, even when used on slower speed networks, due to superior buffering.

3.7 - What is an appropriate "first system" to learn OpenBSD on?

• Platform: Use a platform you are familiar with already. When you are learning a new operating system, it is a very bad time to also be learning a new platform. We'll assume you are going to be using the i386 or amd64 platforms here, as they are probably the ones most people are familiar with. Once you are familiar with OpenBSD, though, it makes a good introduction to other platforms.
• Processor: 100MHz Pentium or better processor. Yes, OpenBSD will run on a 25MHz 80486, but you won't want to do the experimenting and messing up and reloading you need to do to really get to know the system on a slow machine. The primary irritation you will first encounter with a processor slower than this is the time it takes to SSH into the box. If you wish to run X, you probably want to move up to at least 200MHz. X actually runs pretty well on a slower machine once loaded, but it takes a while to load and start.
• 64M RAM or better: If you wish to run X, 128M would be a better starting point.
• Hard disk: A 1G hard disk will give you an easy install of a simple system, such as a firewall, DNS server, or similar. If you wish to rebuild the system from source, you will probably want a 4G disk, and if you wish to rebuild X as well, you will want 6G or bigger. IDE is recommended to start with. If you have a much larger disk, don't feel the obligation to allocate all the disk initially -- there is nothing wrong with leaving 72G of an 80G hard disk unallocated if all you need is 8G.
• Network adapter: Use a PCI adapter. If you are planning on putting multiple network adapters in the machine, write the MAC address on the spine of the card before putting the cover on. While the urge to use that old ISA adapter you have may be strong, resist. You probably don't remember how to properly configure it.
• Multibooting: For your first OpenBSD installation, don't attempt to multiboot with another OS. Multibooting is a difficult process to get right, and you must understand all the OSs involved well before attempting this, which is clearly not the case on your first installation. It is very possible you could accidently delete all data on the system. Rather, use a dedicated computer, or at least, a dedicated disk on a machine.
• Laptops: While many laptops work very well with OpenBSD, they are sometimes not the easiest systems to get running well, so a laptop might not be the best choice for your first OpenBSD install. However, once you are comfortable with OpenBSD, a laptop can be a very useful tool.
• New hardware: Brand new, cutting-edge hardware is sometimes not yet supported by OpenBSD, so for your first OpenBSD system, a slightly older machine is recommended.

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