OpenBSD Hardware


OpenBSD supports a wide variety of hardware architectures: i386, Alpha, 32- and 64-bit Sparc, both the 68000 and PowerPC varieties of Macintosh, and a variety of less well-known platforms. Take a look at http://www.OpenBSD.org/plat.html for a full list of supported platforms. This page contains links to a page for each hardware platform, in which the state of hardware support is discussed in full detail. For example, the i386 page gives a full list of all i386-compatible hardware supported in the latest development version of OpenBSD, -current (see Chapter 14).

This chapter covers the i386 platform, (aka "80386-compatible" or "Standard PC"), which includes the 386, 486, and Pentium lines and their descendants. They're the most common machines, and you probably have one sitting around you could use to learn on. In fact, even old systems can run OpenBSD; you probably have something in a back closet that would do nicely. Many of the examples in this book were performed on a Pentium 166 with 48MB RAM and a stack of 2GB hard disks. (The extra hard disks weren't necessary, but I had them, and a computer can always use more disk space.) We're going to cover installing OpenBSD on both a dedicated machine and on a few varieties of dual-boot systems.

Although OpenBSD will work on ancient hardware, that hardware needs to be in good shape. If your old Pentium box kept crashing because it has bad RAM, it won't behave any better with OpenBSD than it does with its current OS. Also, OpenBSD will be most useful with certain minimum hardware configurations. Here are some basic recommendations, based on my own experiences. These are all i386-based; if you have some other hardware platform, you can draw on these and make your own comparisons.

Proprietary Hardware

Some hardware vendors over the last ten years thought that it was a good idea to keep their hardware interfaces secret, so that competitors wouldn't be able to copy their designs. This has generally proven to be a bad idea; a flood of commodity parts has largely trampled this sort of hardware in recent years.

Developing device drivers for a piece of hardware without the interface specifications is quite difficult. Some hardware can be supported well without full documentation, such as Intel's EtherExpress network cards, and is common enough to make struggling through the lack of documentation worthwhile. Other hardware simply cannot be supported without full and complete documentation, such as Sun's Ultra-SPARC III processor.

If an OpenBSD developer has specifications for a piece of hardware and interest in that same hardware, he'll probably implement support for it. If not, that hardware won't work. In most cases, unsupported proprietary hardware can be replaced with better and less expensive open versions.

Processor

Your brand of processor is really irrelevant. OpenBSD doesn't care if it's running on an Intel, AMD, or IBM, or even an old Cyrix or one of those nifty Transmeta processors. It simply probes the CPU on booting and uses whatever chip features it recognizes. I've run very effective firewalls on 486 machines, easily handling a T1 of traffic. Still, I would recommend that you get 100 MHz or faster CPU. Some of the demonstrations in this book take less than 15 minutes on modern AMD1800+ and days on a 25 MHz 486.

Although OpenBSD will run on a multiple-processor system, it will only use one processor. If you have a choice between an SMP system and one with a single processor, you may as well just use the single-CPU machine for OpenBSD.

Memory (RAM)

Memory is good, and the more memory you have the happier you will be. In fact, adding RAM will do more than anything else to accelerate your system. You should have at least 16MB of RAM at a bare minimum, and preferably at least 32. Mind you, if you can get a couple of gigs of RAM in your system, OpenBSD will take full advantage of it.

Most weird crashes and unexplainable problems can be traced back to bad memory, so be certain that the memory you are using is good. Memory is the most likely failure point in an old machine.

Hard Drives

Hard drives can be a big performance bottleneck. While IDE drives are cheaper than bricks, they can slow down your system roughly as well as bricks can. A SCSI disk system can transfer data to and from each and every drive on the SCSI bus at the full speed of the SCSI controller, while an IDE controller splits its available throughput between the drives on the bus. Also, a SCSI controller can have up to 15 drives, while an IDE controller can have no more than 2. In a throughput competition, I'll back 15 drives moving at full speed against 2 drives moving at an average of half-speed any day.

Still, if all you have are IDE drives, you can do some things to alleviate these problems. Most important, put your hard disks on separate controllers! Many systems now have a hard drive on one IDE controller and a CD-ROM on the other. When you add a second hard drive, put it on the same controller as the CD-ROM drive. You probably won't be using the CD-ROM nearly as often as you use the hard drive, after all, and this will reduce contention on each IDE channel.

You'll be happiest with at least 1GB of disk on your system, though I'm assuming in this book that you have at least 10GB of disk. If you have a smaller disk, you'll want to be careful to clean up after yourself. For example, at one point I recommend keeping old source code around for later use; if you don't have enough disk space, don't do that!




Absolute Openbsd(c) Unix for the Practical Paranoid
Absolute OpenBSD: Unix for the Practical Paranoid
ISBN: 1886411999
EAN: 2147483647
Year: 2005
Pages: 298

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