What every Linux user needs to know about BSD

Copyright © 1999 Chris Coleman

I like to think of BSD as a set of tools, like a ratchet set or a set of screwdrivers. Each tool is part of the same set, yet has a different and unique role to play. If you are planning on using BSD in the near future, it helps to have an understanding of which BSD to choose to get your job done.

If we take a broad look at the BSD toolbox, we will find that there are five BSDs. In alphabetical order, they are: BSDI, FreeBSD, NetBSD, OpenBSD, and PicoBSD. Even though they all have the same heritage, stemming from the University California Berkeley 4.4BSD and 386BSD source code, they have diverged and specialized.

History in a very small nut-shell.

When the open source BSD projects first began NetBSD and FreeBSD diverged because NetBSD wanted to go multi-platform and FreeBSD wanted to concentrate on the Intel platform. BSDI took the code and became a commercial developer of BSD, competing with the other major UNIX flavors. The BSDI source code is no longer open. Later, OpenBSD diverged from NetBSD and began focusing on security and cryptography. PicoBSD is based on the notion that BSD should fit on a single floppy disk. PicoBSD is based on the current sources of FreeBSD and is actively maintained by the FreeBSD community.

Supported Platforms:

The biggest way that the BSDs differ from each other is in their supported platforms, or in other words, the computer types that they will run on. NetBSD's motto is "Of course it runs NetBSD", and given the list of supported platforms, I tend to agree. Since OpenBSD is derived from the NetBSD code, the official supported platforms are identical. However, NetBSD has unofficial platforms that OpenBSD does not support. OpenBSD does claim that it is easy to port the code over if you want the platform supported.

FreeBSD supports the Intel based platform, ie 386, 486, Pentium, PII, PIII, etc. Only just recently have they added support for the DEC Alpha processor. PicoBSD and BSDI currently support only Intel Processors.

NetBSD & OpenBSD Supported Platforms:

Emulation

NetBSD and OpenBSD both support binary emulation of SVR4 (Solaris), FreeBSD, Linux, BSDI, SunOS, and HP-UX.

FreeBSD supports Linux, BSDI, and SCO binaries.

FreeBSD, NetBSD, and OpenBSD have very good Linux support. Some Linux binaries are reported to work better than the native binary supplied by the same software vendor, this has been the case with the FreeBSD Netscape binary from time to time. In practical terms, this means many FreeBSD users are using the Linux binary of Netscape until the FreeBSD binary support from Netscape gets better. Also it has been reported that some Linux binaries run faster on BSD than they did on Linux.

BSDI will soon support Linux binaries.

MSDOS binaries are supported using a variety of add-on packages, such as bochs, pcemu, and doscmd. These packages allow you to run DOS binaries on any of the above systems.

Windows emulation is provided by the Wine project on FreeBSD, NetBSD and OpenBSD.

NetBSD also claims to have binary support for the applications for the native operating system of almost every port that they officially support. In other words, Sun machines run SunOS binaries and so forth.

PicoBSD's purpose -- a drastically stripped-down system -- doesn't lend itself to needing binary support for other OSes.

Development model

The development model of BSD is similar among all the open source varieties, yet very different from Linux. Each BSD has its own "core" team that makes the decisions and drives the project towards it goals. A larger body of "Committers" are developers who have rights to make changes to the base source code set. The whole group works together with the users to improve and develop new features of the OS. The source code is controlled using CVS, a source code control mechanism that allows several people to develop at the same time and not conflict or interfere with each other. The core team and the developers have "commit" rights, or write rights, to the master source code set. Regular users have read-only access through CVS web sites, or CVS programs that allow you to download the source code from the internet or receive it through E-mail. Through a program called 'cvsup', users can download the source code for the newest revisions or revert to an older release and completely rebuild or merely patch their systems.

Each BSD group is a complete distribution of kernel and userland code.

X Window System

A Graphical User Interface is supplied for free from www.Xfree86.org and native binaries are available for FreeBSD, NetBSD and OpenBSD. The standard window managers, such as kde, enlightenment, fvwm, fvwm95, windowmaker, afterstep, and many more are available as packages or ported software.

It is impossible to distinguish between a well configured GUI on BSD from the GUI on Linux because they both use the same version of XFree86.

License

BSD is licensed very differently from Linux. Both are OpenSource licenses, however the GPL that Linux is licensed under imposes several restrictions that the BSD license does not. I am not going to go into detail here about those restrictions, however the BSD license basically allows you to use the code as you wish as long as you give credit to the people who wrote it.

Summary

If you are planning to use BSD as a replacement to or in conjunction with Linux, you will want to choose a BSD that meets your needs:

Chris Coleman, chrisc@vmunix.com