The m0n0wall project is designed to provide a complete firewall solution, ideally aimed at the embedded PC market, although the operating system can be used on any PC with suitable networking hardware. The operating system is based on a bare-bones version of FreeBSD and is combined with a Web server and PHP (for management and administration) and a suite of utilities that control and support the firewall operation.
m0n0wall is unique in that it uses PHP both to manage the system and to control the boot-up process. It uses XML to store configuration information for the entire operating system. As a firewall, it provides IP filtering, DHCP, DNS forwarding, DynDNS support, IPsec, and SNMP. Designed to work with embedded hardware, the entire operating system takes up less than 6 MB of memory. This makes it an ideal fit for small-scale embedded hardware devices, which often have less than 16 MB of RAM split between disk-like storage and active memory for running the operating system.
The m0n0wall Web site has more information.
In some situations, you may want to run an operating system to get data off of a machine but do not want to alter or affect the running operating system and in particular the hard drive. Alternatively, perhaps you want to use some old hardware and no longer have a suitable hard drive, or merely want to create a usable system that is easy to update and deploy.
PicoBSD is such an operating system. The entire operating systems fits onto a standard 1.44 MB floppy and runs on hardware with a configuration as simple as a 386SX CPU and just 8 MB of RAM. Because it runs from a floppy, it can be an effective way to deploy a simple workstation, copy that data over a network, or act as a small, dedicated, network server — perhaps as a network router or firewall.
PicoBSD is available in four standard versions: dial-up (which acts as a dial-up-based Internet router), a generic networking version, a specialized router version (which includes routing and firewall facilities), and a dial-in server version that can provide access to the network over a dial-up connection. In addition to being thoroughly practical in the various versions that are available, PicoBSD is customizable, and tools are available to create a floppy-based BSD operating system to suit specific needs.
More information on PicoBSD can be found on the PicoBSD Project.
LiveCD enables you to test and run an operating system directly from the CD without having to install the operating system on your machine. The use of LiveCD is increasing as a way to test and try out operating systems in an environment not destructive to the current installation. Live CD also provide the ability to run diagnostic and testing utilities on an installation.
Because everything is running from the CD, there are some limitations. Speed is an obvious one. A CD ROM is not as fast as a hard drive. You may also be limited in terms of the supported hardware (because of limited driver availability), memory, and storage (because the CDs tries to avoid using disks automatically), and there is no easy way to customize the operating system, it will always run from the CD in the same way. This can mean that changes and modifications, particularly to the configuration, will be lost during a reboot. It also means new software generally cannot be added to installations, unless it is accessed from a remote filesystem.
Although these problems are frustrating, the flexibility and functionality LiveCD offers generally far outweighs any potential problems. Three well-known BSD-based LiveCDs are FreeSBIE, Frenzy, and GuLIC-BSD.
The Frenzy Live CD is similar to Knoppix and LiveCD. It is designed as a BSD-based rescue and recovery CD for repairing hard disks, installing operating systems, and performing virus scans and other maintenance tasks that would be less efficient, reliable, or extensive when executed on a live operating system.
Frenzy is an ongoing project that includes an extensive number of utilities, such as file management and compression tools, hardware tests, antivirus software, SQL clients, network analyzers, and various viewers for different file types.
Frenzy’s project page includes active discussions on the next version of the project as well as issues and problems with current releases.
FreeSBIE is a LiveCD based on the FreeBSD operating system. At presstime, the most recent update to the project was made in December 2004, although the CD is still downloadable and is perfectly valid as a FreeBSD Live CD. As a benefit, FreeSBIE also includes an installer that can be used to install FreeSBIE to your hard drive.
In essence, FreeSBIE is a LiveCD that also provides a convenient way to install the operating system onto the machine. Additional information, including how to download FreeSBIE, can be found on the FreeSBIE Project page.
GuLIC-BSD is a version of the FreeSBIE release, localized entirely for Spanish (specifically Castilian). More information can be found on the GuLIC-BSD project page.