These classnotes are depreciated. As of 2005, I no longer teach the classes. Notes will remain online for legacy purposes

UNIX02/What Is FreeBSD

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From the FreeBSD webpage:
FreeBSD is an advanced operating system for x86 compatible, DEC Alpha, IA-64, PC-98 and UltraSPARC architectures. It is derived from BSD UNIX, the version of UNIX developed at the University of California, Berkeley.

FreeBSD is a very stable and mature UNIX-variant. While Linux may still be in its "infacy" (which is not to say it can't be just as secure or stable as FreeBSD), FreeBSD has as its roots a true derivative of AT&T's UNIX, 4.2BSD, which dates back to 1982. In 1990, a gutted version of 4.2BSD was released as source code and worked into an Intel-based BSD known as 386BSD.

386BSD never became a stable OS, as in 1993 two divergent groups split off to form separate variants: NetBSD and FreeBSD. Later, in 1996, another project split off from NetBSD: OpenBSD.

If all these splits make your head spin, you are not alone. It's because of these splits that the Linux kernel developers are so paranoid about "forking"-- as each break divided the BSD community.

NetBSD and OpenBSD are commonly considered more secure than FreeBSD while FreeBSD is much easier to work with. However, this is only partially true: FreeBSD is, indeed, much simpler to set up and maintain, but it can be just as secure as NetBSD or OpenBSD with the proper tuning.

FreeBSD is presently used by many high-profile web-sites such as Yahoo! and Unfortunately, the internet/intranet services area is really the only area that FreeBSD has got much of a foothold in. FreeBSD does not scale down to the embedded market as easily as Linux, and is not as easily supported on main-frames. So it is not quite as versatile as Linux.

However, FreeBSD does have native Linux binary support, and can be much more efficient and speedy "out of the box" than your standard binary-based Linux distribution. Plus, if you have some sort of broadband internet connection, maintaining and updating your FreeBSD can be easier than nearly every other Linux distribution.

FreeBSD disk slices

One of the areas where Linux really isn't a good example of a typical UNIX system is with respect to hard drive devices. Under Linux, we have a very simple and effective naming scheme.

However, the traditional UNIX world deals with things known as "slices" which may be partitions and may be sub-partitions inside of partitions. FreeBSD follows this UNIX tradition.

The hard drives are labelled in the following way in Linux and FreeBSD:

                      Linux           FreeBSD
 First IDE drive      /dev/hda        /dev/wd0
 Second IDE drive     /dev/hdb        /dev/wd1
 First SCSI drive     /dev/sda        /dev/sd0
 Second SCSI drive    /dev/sdb        /dev/sd1

The partitions (FreeBSD slices) on an IDE drive are labelled in the following way (/dev/hda is used as an example):

                              Linux           FreeBSD
 First primary partition      /dev/hda1       /dev/wd0s1
 Second primary partition     /dev/hda2       /dev/wd0s2
 Third primary partition      /dev/hda3       /dev/wd0s3
 Fourth primary partition     /dev/hda4       /dev/wd0s4

Correlate to LVMS


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Last edited May 9, 2003 6:38 pm (diff)
(C) Copyright 2003 Samuel Hart
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