What is BSD (Berkeley Software Distribution)?

BSD stands for Berkeley Software Distribution. It originated at the University of California, Berkeley. This operating system comes from the Unix system.

Many contributions helped shape BSD over time. Today, it remains influential in various software projects. Overall, BSD is recognized for its stability and performance.

What is the BSD Operating System?

In the early years, the Unix system’s creators allowed AT&T, Bell Labs, and the University of California, Berkeley to use its source code. They could adapt it to meet their needs.

In the 1970s and 1980s, Berkeley used Unix for operating systems research. Later, AT&T withdrew permission for commercial use. In response, Berkeley encouraged the development of its own version.

This version was based on their contributions to Unix. It allowed for academic distribution and reduced restrictions on copying. Over time, Berkeley made it easier to share and use the new version.

BSD History

Beginning with PDP-11

In the 1970s, Bell Labs released its first Unix distributions. These included the operating system’s source code. As a result, university developers could replace and extend Unix. Berkeley’s first Unix system ran on the PDP-11, starting in 1974. It has served the computer science department since its beginning.

Other universities soon took an interest in Berkeley’s software. In 1977, graduate Bill Joy recorded and sent tapes for the first Berkeley Software Distribution. BSD 1 was not a complete operating system. Instead, it supplemented the sixth version of Unix. It mainly included a Pascal compiler and a text editor called “ex,” created by Joy.

Next, BSD 2 came out in 1978. This version featured updates from 1BSD and introduced two new programs: the Vi text editor and the C shell. Following these releases, adaptations made the distributions compatible with the VAX architecture and the PDP-11 architecture.

By 1983, BSD-2.9 included the BSD 4.1c code. This marked the first distribution recognized as a complete operating system. The latest release, version 2.11, appeared in 1992. Updates continued until 2003, thanks to dedicated volunteers.

VAX Versions

In 1978, a VAX computer was installed in Berkeley. However, the Unix adaptation for VAX, known as UNIX/32V, didn’t utilize the system’s virtual memory.

As a result, Berkeley students worked hard to rewrite the 32V core. Their goal was to harness the power of virtual memory. By the end of 1979, they launched a new core called 3BSD. This version included 2BSD adaptations and 32V utilities optimized for the VAX architecture.

Additionally, BSD-3 became known as the BSD/vmunix kernel images. This was also referred to as VMUNIX, and later BSD-4.4.

The success of BSD-3 played a crucial role in Berkeley’s Computer System Research Group (CSRG). They collaborated with DARPA to develop a standard Unix platform for VLSI project research.

BSD 4

Launched in November 1980, this version brought many improvements. First, it enhanced cash control. Next, it improved mail delivery.

Users enjoyed more reliable signals, too. Additionally, it included the Curses programming library.

These updates made the system more effective and user-friendly. Overall, it was a significant upgrade from the previous version.

BSD 4.1

This release came out in June 1981. It responded to BSD’s criticism of VMS, the main operating system for the VAX architecture.

Bill Joy developed this version. It includes features similar to VMS. Initially, it was called BSD-5. However, it was later renamed. This change aimed to avoid confusion with the launch of AT&T Unix System V.

BSD 4.2

This version took two years to implement. It included significant improvements. Before the official release, three intermediate versions were launched.

Version 4.1a had a modified version of BBN’s TCP/IP pre-application. Then, 4.1b introduced the new Berkeley Fast File System, created by Marshall Kira McKusick. Finally, 4.1c was an internal release used during the last months of 4.2 development.

The official distribution came out in August 1983. Bill Joy became the first distributor after joining Sun Microsystems. Since then, Mike Karels and Marshall Kira McKusick have taken over the project.

BSD 4.3

BSD 4.3 was released in June 1986. This version included many new features. However, the TCP/IP implementation differed significantly from the original by BBN.

After extensive testing by DARPA, they found that version 4.2 was better. Therefore, they decided to keep it in the latest distribution.

Following version 4.3, a new direction emerged. Future versions would be based on different architectures than the old VAX. At that time, the Power 6/32 platform from Computer Consoles Inc. seemed promising. Unfortunately, its developers soon abandoned the project.

Still, the 4.3-Tahoe adaptation highlighted the value of separating machine-dependent and independent code. This separation allowed for better portability in the future.

Until then, all BSD versions included AT&T’s proprietary code. Using this code required an expensive license. Many external organizations wanted a separate distribution of the private network code from AT&T.

They sought to avoid these costly licenses. In response, Network Band 1 (Net/1) was created. It excluded AT&T’s proprietary code and was released in 1989. This version was freely distributed under permissive licensing terms.

BSD 4.3-Reno

4.3-Reno was released in 1990 and was an internal-use version used in its construction. This distribution was moving towards compatibility with POSIX, and according to some, it was far from philosophy as it was based on the POSIX V system.

Net/2 and Legal Issues

After Net/1, Keith Bostic wanted to publish more episodes. He suggested using the same Net/1 license, but with non-AT&T-BSD content. To achieve this, he started a project. The goal was to implement standard Unix utilities without using AT&T code.

Within 18 months, most of AT&T’s registered public services were replaced. Only a few registered files remained in the core system. Eventually, these files were also removed. As a result, Net/2 became an almost complete operating system that could be freely distributed.

Net/2 led to two adaptations for the Intel 80386 architecture. William Jolliz created 386BSD, while BSD/386 was developed by Berkeley Software Design (BSDi). Although 386BSD was short-lived, it served as the foundation for FreeBSD and NetBSD.

Meanwhile, BSDi faced legal issues with AT&T, which owned System V rights. In 1992, AT&T filed a lawsuit. This lawsuit delayed Net/2’s distribution until they resolved the claims.

During this time, both Linux and 386BSD evolved. Linus Torvalds later stated that if a free Unix-based operating system existed for the 386 architecture, he might not have created Linux. This situation had a significant impact, shaping the software landscape.

BSD 4.4

The case concluded in favor of Berkeley in January 1994. Only three of the 18,000 files were removed. Moreover, 70 files were updated to reflect AT&T’s property rights.

In June 1994, Berkeley released two versions. One was called 4.4-Lite, which anyone could distribute freely. The second, 4.4-Encumbered, was for AT&T vendors only.

Berkeley created the final distribution, BSD 4.4-Lite Version 2, in 1995. This happened after the CSRG was dissolved. Since then, many distributions derived from BSD 4.4 have emerged. These include FreeBSD, OpenBSD, and NetBSD.

Additionally, the permitted license allows including code from other operating systems. This applies to both free and registered systems. For instance, Microsoft used BSD-derived code in its Windows TCP/IP application. They also recompiled versions of BSD tools for network use.

Furthermore, Darwin, the core of Apple’s Mac OS X, partially came from FreeBSD 5. Other commercial Unix-based systems, like Solaris, also utilize BSD code.

Contributions

Berkeley developed several sub-operating systems. These include SunOS, FreeBSD, NetBSD, OpenBSD, and Mac OS X.

Additionally, Berkeley made important contributions to operating systems as a whole. Their work has influenced many areas in this field. As a result, their impact is still felt today.

• Optional paged virtual memory management
• Business control
• Fast File System
• TCP/IP protocol (almost all TCP applications are derived from 4.4BSD-Lite)