Briefly, FreeBSD is a UNIX® like operating system for the Alpha/AXP, AMD64 and Intel® EM64T, i386™ IA-64, PC-98, and UltraSPARC® platforms based on U.C. Berkeley's “4.4BSD-Lite” release, with some “4.4BSD-Lite2” enhancements. It is also based indirectly on William Jolitz's port of U.C. Berkeley's “Net/2” to the i386, known as “386BSD”, though very little of the 386BSD code remains. A fuller description of what FreeBSD is and how it can work for you may be found on the FreeBSD home page.

FreeBSD is used by companies, Internet Service Providers, researchers, computer professionals, students and home users all over the world in their work, education and recreation.

For more detailed information on FreeBSD, please see the FreeBSD Handbook.

The goal of the FreeBSD Project is to provide software that may be used for any purpose and without strings attached. Many of us have a significant investment in the code (and project) and would certainly not mind a little financial compensation now and then, but we definitely do not insist on it. We believe that our first and foremost “mission” is to provide code to any and all comers, and for whatever purpose, so that the code gets the widest possible use and provides the widest possible benefit. This is, we believe, one of the most fundamental goals of Free Software and one that we enthusiastically support.

That code in our source tree which falls under the GNU General Public License (GPL) or GNU Library General Public License (LGPL) comes with slightly more strings attached, though at least on the side of enforced access rather than the usual opposite. Due to the additional complexities that can evolve in the commercial use of GPL software, we do, however, endeavor to replace such software with submissions under the more relaxed FreeBSD license whenever possible.

Yes. Those restrictions do not control how you use the code, merely how you treat the FreeBSD Project itself. If you have serious license concerns, read the actual license. For the simply curious, the license can be summarized like this.

• Do not claim that you wrote this.

• Do not sue us if it breaks.

For most people, yes. But this question is not quite that cut-and-dried.

Most people do not actually use an operating system. They use applications. The applications are what really use the operating system. FreeBSD is designed to provide a robust and full-featured environment for applications. It supports a wide variety of web browsers, office suites, email readers, graphics programs, programming environments, network servers, and just about everything else you might want. Most of these applications can be managed through the Ports Collection.

If you need to use an application that is only available on one operating system, you simply cannot replace that operating system. Chances are there is a very similar application on FreeBSD, however. If you want a solid office or Internet server, a reliable workstation, or just the ability to do your job without interruptions, FreeBSD will almost certainly do everything you need. Many computer users across the world, including both novices and experienced UNIX administrators, use FreeBSD as their only desktop operating system.

If you are migrating to FreeBSD from some other UNIX environment, you already know most of what you need to. If your background is in graphic-driven operating systems such as Windows® and older versions of Mac OS®, expect to invest additional time learning the UNIX way of doing things. This FAQ and the FreeBSD Handbook are excellent places to start.

• It may be used free of charge, even by commercial users.

• Full source for the operating system is freely available, and the minimum possible restrictions have been placed upon its use, distribution and incorporation into other work (commercial or non-commercial).

• Anyone who has an improvement or bug fix is free to submit their code and have it added to the source tree (subject to one or two obvious provisions).

• It is worth pointing out that the word “free” is being used in two ways here, one meaning “at no cost”, the other meaning “you can do whatever you like”. Apart from one or two things you cannot do with the FreeBSD code, for example pretending you wrote it, you can really do whatever you like with it.

James Howard wrote a good explanation of the history and differences between the various projects for DaemonNews, called The BSD Family Tree which goes a fair way to answering this question.

At this point in FreeBSD's development, there are three parallel development branches; releases are being made from two of the three branches. The 4.X series of releases is being made from the 4-STABLE branch and the 5.X series of releases is being made from 5-STABLE. It will be some time in mid-to-late 2005 before the first release will be made from the 6-CURRENT branch; that release (6.0) will be aimed at early adopters.

Up until the release of 5.3, the 4.X series was the one known as -STABLE. However, as of 5.3, 5.X has been designated the new -STABLE and 4.X will no longer see much new development. Instead, it will be designated for an "extended support" status and receive only fixes for major problems (such as security-related fixes.)

Version 6.0 is the latest release from the 5-STABLE branch; it was released in Nov 2005. Version 5.4 is the latest release from the 4-STABLE branch; it was released in May 2005.

Briefly, -STABLE is aimed at the ISP, corporate user, or any user who wants stability and a minimal number of changes compared to the new (and possibly unstable) features of the latest -CURRENT snapshot. Releases can come from either branch, but -CURRENT should only be used if you are prepared for its increased volatility (relative to -STABLE, that is).

Releases are made every few months. While many people stay more up-to-date with the FreeBSD sources (see the questions on FreeBSD-CURRENT and FreeBSD-STABLE) than that, doing so is more of a commitment, as the sources are a moving target.

More information on FreeBSD releases can be found on the Release Engineering page on the FreeBSD Web site.

FreeBSD-CURRENT is the development version of the operating system, which will in due course become the new FreeBSD-STABLE branch. As such, it is really only of interest to developers working on the system and die-hard hobbyists. See the relevant section in the handbook for details on running -CURRENT.

If you are not familiar with the operating system or are not capable of identifying the difference between a real problem and a temporary problem, you should not use FreeBSD-CURRENT. This branch sometimes evolves quite quickly and can be un-buildable for a number of days at a time. People that use FreeBSD-CURRENT are expected to be able to analyze any problems and only report them if they are deemed to be mistakes rather than “glitches”. Questions such as “make world produces some error about groups” on the -CURRENT mailing list may be treated with contempt.

Every day, snapshot releases are made based on the current state of the -CURRENT and -STABLE branches. Distributions of the occasional snapshot are made available. The goals behind each snapshot release are:

• To test the latest version of the installation software.

• To give people who would like to run -CURRENT or -STABLE but who do not have the time or bandwidth to follow it on a day-to-day basis an easy way of bootstrapping it onto their systems.

• To preserve a fixed reference point for the code in question, just in case we break something really badly later. (Although CVS normally prevents anything horrible like this happening :)

• To ensure that all new features and fixes in need of testing have the greatest possible number of potential testers.

No claims are made that any -CURRENT snapshot can be considered “production quality” for any purpose. If you want to run a stable and fully tested system, you will have to stick to full releases, or use the -STABLE snapshots.

Snapshot releases are directly available from ftp://current.FreeBSD.org/pub/FreeBSD/snapshots/.

Snapshots are generated, on the average, daily for all actively developed branches.

Back when FreeBSD 2.0.5 was released, FreeBSD development branched in two. One branch was named -STABLE, one -CURRENT. FreeBSD-STABLE is intended for Internet Service Providers and other commercial enterprises for whom sudden shifts or experimental features are quite undesirable. It receives only well-tested bug fixes and other small incremental enhancements. FreeBSD-CURRENT, on the other hand, has been one unbroken line since 2.0 was released, leading towards 5.3-RELEASE (and beyond). Just before 5.3-RELEASE, the 5-STABLE branch was created, and FreeBSD-CURRENT became 6-CURRENT. For more detailed information, see “ FreeBSD Release Engineering: Creating the Release Branch”.

The 2.2-STABLE branch was retired with the release of 2.2.8. The 3-STABLE branch has ended with the release of 3.5.1, the final 3.X release. The only changes made to either of these branches will be, for the most part, security-related bug fixes. Support for the 4-STABLE branch will continue for some time but focus primarily on security-related bug fixes and other serious issues.

5-STABLE is the actively developed -STABLE branch. The latest release on the 5-STABLE branch is 6.0-RELEASE, which was released in Nov 2005.

The 6-CURRENT branch is the actively developed -CURRENT branch toward the next generation of FreeBSD. See What is FreeBSD-CURRENT? for more information on this branch.

The Release Engineering 团队 <re@FreeBSD.org> releases a new version of FreeBSD about every four months, on average. Release dates are announced well in advance, so that the people working on the system know when their projects need to be finished and tested. A testing period precedes each release, in order to ensure that the addition of new features does not compromise the stability of the release. Many users regard this caution as one of the best things about FreeBSD, even though waiting for all the latest goodies to reach -STABLE can be a little frustrating.

More information on the release engineering process (including a schedule of upcoming releases) can be found on the release engineering pages on the FreeBSD Web site.

For people who need or want a little more excitement, binary snapshots are made daily as discussed above.

The key decisions concerning the FreeBSD project, such as the overall direction of the project and who is allowed to add code to the source tree, are made by a core team of 9 people. There is a much larger team of more than 300 committers who are authorized to make changes directly to the FreeBSD source tree.

However, most non-trivial changes are discussed in advance in the mailing lists, and there are no restrictions on who may take part in the discussion.

Every significant release of FreeBSD is available via anonymous FTP from the FreeBSD FTP site:

• The latest 5-STABLE release, 6.0-RELEASE can be found in the 6.0-RELEASE directory.

• Snapshot releases are made daily for the -CURRENT branch, these being of service purely to bleeding-edge testers and developers.

• The latest 4-STABLE release, 5.4-RELEASE can be found in the 5.4-RELEASE directory.

• 5.X snapshots are usually made daily.

Information about obtaining FreeBSD on CD, DVD, and other media can be found in the Handbook.

Information on setting up a FreeBSD mirror can be found in the Mirroring FreeBSD article.

The Problem Report database of all user change requests may be queried by using our web-based PR query interface.

The send-pr(1) command can be used to submit problem reports and change requests via electronic mail. Alternatively, the web-based problem report submission interface can be used to submit problem reports through a web browser.

Before submitting a problem report, please read Writing FreeBSD Problem Reports, an article on how to write good problem reports.

There are multiple ways to mirror the Web pages.

• You can retrieve the formatted files from a FreeBSD CVSup server using the application net/cvsup. The file /usr/share/examples/cvsup/www-supfile contains an example CVSup configuration file for web mirrors.

• You can download the web site source code from any FreeBSD FTP server using your favorite ftp mirror tool. Keep in mind that you have to build these sources before publishing them. Start mirroring at ftp://ftp.FreeBSD.org/pub/FreeBSD/FreeBSD-current/www/.

Please check the Documentation list on the main FreeBSD web site.

The project produces a wide range of documentation, available online from this link: http://www.FreeBSD.org/docs.html. The same documents are available as packages, that you can easily install on your FreeBSD system. More details on documentation packages can be found in the next paragraphs.

In addition, the Bibliography at the end of this FAQ, and the one in the Handbook reference other recommended books.

Yes. The documentation is available in a number of different formats and compression schemes on the FreeBSD FTP site, in the /pub/FreeBSD/doc/ directory.

The documentation is categorized in a number of different ways. These include:

• The document's name, such as faq, or handbook.

• The document's language and encoding. These are based on the locale names you will find under /usr/share/locale on your FreeBSD system. The current languages and encodings that we have for documentation are as follows:

  Name	Meaning
  en_US.ISO8859-1	US English
  de_DE.ISO8859-1	German
  es_ES.ISO8859-1	Spanish
  fr_FR.ISO8859-1	French
  it_IT.ISO8859-15	Italian
  ja_JP.eucJP	Japanese (EUC encoding)
  ru_RU.KOI8-R	Russian (KOI8-R encoding)
  zh_TW.Big5	Chinese (Big5 encoding)

  注意: Some documents may not be available in all languages.

• The document's format. We produce the documentation in a number of different output formats. Each format has its own advantages and disadvantages. Some formats are better suited for online reading, while others are meant to be aesthetically pleasing when printed on paper. Having the documentation available in any of these formats ensures that our readers will be able to read the parts they are interested in, either on their monitor, or on paper after printing the documents. The currently available formats are:

  Format	Meaning
  html-split	A collection of small, linked, HTML files.
  html	One large HTML file containing the entire document
  pdb	Palm Pilot database format, for use with the iSilo reader.
  pdf	Adobe's Portable Document Format
  ps	PostScript
  rtf	Microsoft's Rich Text Format[a]
  txt	Plain text
  表注: a. Page numbers are not automatically updated when loading this format into Word. Press CTRL+A, CTRL+END, F9 after loading the document, to update the page numbers.

• The compression and packaging scheme. There are three of these currently in use.

  1. Where the format is html-split, the files are bundled up using tar(1). The resulting .tar file is then compressed using the compression schemes detailed in the next point.

  2. All the other formats generate one file, called book.format (i.e., book.pdb, book.html, and so on).

     These files are then compressed using two compression schemes.

     Scheme	Description
     zip	The Zip format. If you want to uncompress this on FreeBSD you will need to install the archivers/unzip port first.
     bz2	The BZip2 format. Less widespread than Zip, but generally gives smaller files. Install the archivers/bzip2 port to uncompress these files.

     So the PostScript version of the Handbook, compressed using BZip2 will be stored in a file called book.ps.bz2 in the handbook/ directory.

After choosing the format and compression mechanism that you want to download, you must then decide whether or not you want to download the document as a FreeBSD package.

The advantage of downloading and installing the package is that the documentation can then be managed using the normal FreeBSD package management comments, such as pkg_add(1) and pkg_delete(1).

If you decide to download and install the package then you must know the filename to download. The documentation-as-packages files are stored in a directory called packages. Each package file looks like document-name.lang.encoding.format.tgz.

For example, the FAQ, in English, formatted as PDF, is in the package called faq.en_US.ISO8859-1.pdf.tgz.

Knowing this, you can use the following command to install the English PDF FAQ package.

# pkg_add ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/packages/faq.en_US.ISO8859-1.pdf.tgz

Having done that, you can use pkg_info(1) to determine where the file has been installed.

# pkg_info -f faq.en_US.ISO8859-1.pdf
Information for faq.en_US.ISO8859-1.pdf:

Packing list:
        Package name: faq.en_US.ISO8859-1.pdf
        CWD to /usr/share/doc/en_US.ISO8859-1/books/faq
File: book.pdf
        CWD to .
File: +COMMENT (ignored)
File: +DESC (ignored)

As you can see, book.pdf will have been installed into /usr/share/doc/en_US.ISO8859-1/books/faq.

If you do not want to use the packages then you will have to download the compressed files yourself, uncompress them, and then copy the appropriate documents into place.

For example, the split HTML version of the FAQ, compressed using bzip2(1), can be found in the doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2 file. To download and uncompress that file you would have to do this.

# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/en_US.ISO8859-1/books/faq/book.html-split.tar.bz2
# bzip2 -d book.html-split.tar.bz2
# tar xvf book.html-split.tar

You will be left with a collection of .html files. The main one is called index.html, which will contain the table of contents, introductory material, and links to the other parts of the document. You can then copy or move these to their final location as necessary.

You can find full information in the Handbook entry on mailing-lists.

You can find full information in the FreeBSD Y2K page.

You can find full information in the Handbook entry on newsgroups.

Yes, most major IRC networks host a FreeBSD chat channel:

• Channel #FreeBSD on EFNet is a FreeBSD forum, but do not go there for tech support or try to get folks there to help you avoid the pain of reading manual pages or doing your own research. It is a chat channel, first and foremost, and topics there are just as likely to involve sex, sports or nuclear weapons as they are FreeBSD. You Have Been Warned! Available at server irc.chat.org.

• Channel #FreeBSDhelp on EFNet is a channel dedicated to helping FreeBSD users. They are much more sympathetic to questions than #FreeBSD is.

• Channel #FreeBSD on DALNET is available at irc.dal.net in the US and irc.eu.dal.net in Europe.

• Channel #FreeBSDHelp on DALNET is available at irc.dal.net in the US and irc.eu.dal.net in Europe. The channel owners also have a web page with useful information about the channel and FreeBSD, available at http://www.freebsdhelp.net/.

• Channel #FreeBSD on UNDERNET is available at us.undernet.org in the US and eu.undernet.org in Europe. Since it is a help channel, be prepared to read the documents you are referred to.

Each of these channels are distinct and are not connected to each other. Their chat styles also differ, so you may need to try each to find one suited to your chat style. As with all types of IRC traffic, if you are easily offended or cannot deal with lots of young people (and more than a few older ones) doing the verbal equivalent of jello wrestling, do not even bother with it.

DaemonNews provides commercial training and support for FreeBSD. More information can be found at their BSD Mall site.

The FreeBSD Mall provides commercial FreeBSD support. You can get more information at their web site.

Any other organizations providing training and support should contact the project in order to be listed here.

For 4.X you need two floppy images: floppies/kernel.flp and floppies/mfsroot.flp. These images need to be copied onto floppies by tools like fdimage or dd(1). In FreeBSD 5.3 and later, the boot floppies have been restructured and you need floppies/boot.flp and all the floppies/kernX files (of which there are currently two).

If you need to download the distributions yourself (for a DOS filesystem install, for instance), below are some recommendations for distributions to grab:

• base/ (bin/ in 4.X)

• manpages/

• compat*/

• doc/

• src/ssys.*

Full instructions on this procedure and a little bit more about installation issues in general can be found in the Handbook entry on installing FreeBSD.

A 3.5 inch (1.44MB) floppy can accommodate 1474560 bytes of data. The boot image is exactly 1474560 bytes in size.

Common mistakes when preparing the boot floppy are:

• Not downloading the floppy image in binary mode when using FTP.

  Some FTP clients default their transfer mode to ascii and attempt to change any end-of-line characters received to match the conventions used by the client's system. This will almost invariably corrupt the boot image. Check the size of the downloaded boot image: if it is not exactly that on the server, then the download process is suspect.

  To workaround: type binary at the FTP command prompt after getting connected to the server and before starting the download of the image.

• Using the DOS copy command (or equivalent GUI tool) to transfer the boot image to floppy.

  Programs like copy will not work as the boot image has been created to be booted into directly. The image has the complete content of the floppy, track for track, and is not meant to be placed on the floppy as a regular file. You have to transfer it to the floppy “raw”, using the low-level tools (e.g. fdimage or rawrite) described in the installation guide to FreeBSD.

Installation instructions can be found in the Handbook entry on installing FreeBSD.

For versions prior to 5.X, you will need a 386 or better PC, with 5 MB or more of RAM and at least 60 MB of hard disk space. The FreeBSD installation process requires somewhat more memory so in practice, 16 MB of RAM is a minimum requirement for a standalone FreeBSD system.

For FreeBSD 5.X and later you will need a 486 or better PC, with 24 MB or more of RAM and at least 150 MB of hard disk space.

All versions of FreeBSD can run with a low end MDA graphics card but to run X11R6, a VGA or better video card is needed.

See also 第 4 章.

Installing FreeBSD 4.X requires at least 5MB RAM, and installing FreeBSD 5.X and later requires at least 8MB.

All versions of FreeBSD prior to 5.X will run in 4MB of RAM, they just cannot run the installation program in 4MB. You can add extra memory for the install process, and then revert to 4MB after the system is running. Or you could move your disk into a system which has sufficient memory, install onto the disk and then swap it back.

You must build a custom kernel to run in 4MB. Someone has even successfully booted FreeBSD with 2 MB RAM, although the system was almost unusable.

Currently there is no way to just make a custom install floppy. You have to cut a whole new release, which will include your install floppy.

To make a custom release, follow the instructions in the Release Engineering article.

Have a look at the multi-OS page.

Install Windows first, then FreeBSD. FreeBSD's boot manager will then manage to boot Windows and FreeBSD. If you install Windows second, it will boorishly overwrite your boot manager without even asking. If that happens, see the next section.

You can reinstall the boot manager FreeBSD comes with in one of three ways:

• Running DOS, go into the tools/ directory of your FreeBSD distribution and look for bootinst.exe. You run it like so:

  ...\TOOLS> bootinst.exe boot.bin
  

  and the boot manager will be reinstalled.

• Boot the FreeBSD boot floppy again and go to the Custom installation menu item. Choose Partition. Select the drive which used to contain your boot manager (likely the first one) and when you come to the partition editor for it, as the very first thing (e.g. do not make any changes) select (W)rite. This will ask for confirmation, say yes, and when you get the Boot Manager selection prompt, be sure to select “Boot Manager”. This will re-write the boot manager to disk. Now quit out of the installation menu and reboot off the hard disk as normal.

• Boot the FreeBSD boot floppy (or CDROM) and choose the “Fixit” menu item. Select either the Fixit floppy or CDROM #2 (the “live” filesystem option) as appropriate and enter the fixit shell. Then execute the following command:

  Fixit# fdisk -B -b /boot/boot0 bootdevice
  

  substituting bootdevice for your real boot device such as ad0 (first IDE disk), ad4 (first IDE disk on auxiliary controller), da0 (first SCSI disk), etc.

A bug in early revisions of IBM's BIOS on these machines mistakenly identifies the FreeBSD partition as a potential FAT suspend-to-disk partition. When the BIOS tries to parse the FreeBSD partition it hangs.

According to IBM[1], the following model/BIOS release numbers incorporate the fix.

It has been reported that later IBM BIOS revisions may have reintroduced the bug. This message from Jacques Vidrine to the FreeBSD 笔记本电脑邮件列表 describes a procedure which may work if your newer IBM laptop does not boot FreeBSD properly, and you can upgrade or downgrade the BIOS.

If you have an earlier BIOS, and upgrading is not an option, a workaround is to install FreeBSD, change the partition ID FreeBSD uses, and install new boot blocks that can handle the different partition ID.

First, you will need to restore the machine to a state where it can get through its self-test screen. Doing this requires powering up the machine without letting it find a FreeBSD partition on its primary disk. One way is to remove the hard disk and temporarily move it to an older ThinkPad (such as a ThinkPad 600) or a desktop PC with an appropriate conversion cable. Once it is there, you can delete the FreeBSD partition and move the hard disk back. The ThinkPad should now be in a bootable state again.

With the machine functional again, you can use the workaround procedure described here to get a working FreeBSD installation.

Getting this to work in the case where you want to dual boot OpenBSD and FreeBSD on the same laptop is left as an exercise for the reader.

You can, but it is a bad idea.

If you are seeing bad block errors with a modern IDE drive, chances are the drive is going to die very soon (the drive's internal remapping functions are no longer sufficient to fix the bad blocks, which means the disk is heavily corrupted); we suggest you buy a new hard drive.

If you have a SCSI drive with bad blocks, see this answer.

If you are seeing things like the machine grinding to a halt or spontaneously rebooting when you try to boot the install floppy, here are three questions to ask yourself:-

1. Did you use a new, freshly-formatted, error-free floppy (preferably a brand-new one straight out of the box, as opposed to the magazine cover disk that has been lying under the bed for the last three years)?

2. Did you download the floppy image in binary (or image) mode? (do not be embarrassed, even the best of us have accidentally downloaded a binary file in ASCII mode at least once!)

3. If you are using Windows 95 or 98 did you run fdimage or rawrite in pure DOS mode? These operating systems can interfere with programs that write directly to hardware, which the disk creation program does; even running it inside a DOS shell in the GUI can cause this problem.

There have also been reports of Netscape® causing problems when downloading the boot floppy, so it is probably best to use a different FTP client if you can.

The usual cause of this problem is a mis-configured CDROM drive. Many PCs now ship with the CDROM as the slave device on the secondary IDE controller, with no master device on that controller. This is illegal according to the ATAPI specification, but Windows plays fast and loose with the specification, and the BIOS ignores it when booting. This is why the BIOS was able to see the CDROM to boot from it, but why FreeBSD cannot see it to complete the install.

Reconfigure your system so that the CDROM is either the master device on the IDE controller it is attached to, or make sure that it is the slave on an IDE controller that also has a master device.

Yes. Use a standard Laplink cable. If necessary, you can check out the PLIP section of the Handbook for details on parallel port networking.

注意: By the “geometry” of a disk, we mean the number of cylinders, heads and sectors/track on a disk. We will refer to this as C/H/S for convenience. This is how the PC's BIOS works out which area on a disk to read/write from.

This causes a lot of confusion among new system administrators. First of all, the physical geometry of a SCSI drive is totally irrelevant, as FreeBSD works in term of disk blocks. In fact, there is no such thing as “the” physical geometry, as the sector density varies across the disk. What manufacturers claim is the “physical geometry” is usually the geometry that they have determined wastes the least space. For IDE disks, FreeBSD does work in terms of C/H/S, but all modern drives internally convert this into block references.

All that matters is the logical geometry. This is the answer that the BIOS gets when it asks the drive “what is your geometry?” It then uses this geometry to access the disk. As FreeBSD uses the BIOS when booting, it is very important to get this right. In particular, if you have more than one operating system on a disk, they must all agree on the geometry. Otherwise you will have serious problems booting!

For SCSI disks, the geometry to use depends on whether extended translation support is turned on in your controller (this is often referred to as “support for DOS disks >1GB” or something similar). If it is turned off, then use N cylinders, 64 heads and 32 sectors/track, where N is the capacity of the disk in MB. For example, a 2GB disk should pretend to have 2048 cylinders, 64 heads and 32 sectors/track.

If it is turned on (it is often supplied this way to get around certain limitations in MS-DOS®) and the disk capacity is more than 1GB, use M cylinders, 63 sectors per track (not 64), and 255 heads, where M is the disk capacity in MB divided by 7.844238 (!). So our example 2GB drive would have 261 cylinders, 63 sectors per track and 255 heads.

If you are not sure about this, or FreeBSD fails to detect the geometry correctly during installation, the simplest way around this is usually to create a small DOS partition on the disk. The BIOS should then detect the correct geometry, and you can always remove the DOS partition in the partition editor if you do not want to keep it. You might want to leave it around for programming network cards and the like, however.

Alternatively, there is a freely available utility distributed with FreeBSD called pfdisk.exe. You can find it in the tools subdirectory on the FreeBSD CDROM or on the various FreeBSD FTP sites. This program can be used to work out what geometry the other operating systems on the disk are using. You can then enter this geometry in the partition editor.

Yes. You must make sure that your root partition is below 1024 cylinders so the BIOS can boot the kernel from it. (Note that this is a limitation in the PC's BIOS, not FreeBSD).

For a SCSI drive, this will normally imply that the root partition will be in the first 1024MB (or in the first 4096MB if extended translation is turned on - see previous question). For IDE, the corresponding figure is 504MB.

FreeBSD recognizes the Ontrack Disk Manager and makes allowances for it. Other disk managers are not supported.

If you just want to use the disk with FreeBSD you do not need a disk manager. Just configure the disk for as much space as the BIOS can deal with (usually 504 megabytes), and FreeBSD should figure out how much space you really have. If you are using an old disk with an MFM controller, you may need to explicitly tell FreeBSD how many cylinders to use.

If you want to use the disk with FreeBSD and another operating system, you may be able to do without a disk manager: just make sure the FreeBSD boot partition and the slice for the other operating system are in the first 1024 cylinders. If you are reasonably careful, a 20 megabyte boot partition should be plenty.

This is classically a case of FreeBSD and DOS or some other OS conflicting over their ideas of disk geometry. You will have to reinstall FreeBSD, but obeying the instructions given above will almost always get you going.

This is another symptom of the problem described in the preceding question. Your BIOS geometry and FreeBSD geometry settings do not agree! If your controller or BIOS supports cylinder translation (often marked as “>1GB drive support”), try toggling its setting and reinstalling FreeBSD.

In general, no. However, we would strongly recommend that you install, at a minimum, the base source kit, which includes several of the files mentioned here, and the sys (kernel) source kit, which includes sources for the kernel. There is nothing in the system which requires the presence of the sources to operate, however, except for the kernel-configuration program config(8). With the exception of the kernel sources, our build structure is set up so that you can read-only mount the sources from elsewhere via NFS and still be able to make new binaries (due to the kernel-source restriction, we recommend that you not mount this on /usr/src directly, but rather in some other location with appropriate symbolic links to duplicate the top-level structure of the source tree).

Having the sources on-line and knowing how to build a system with them will make it much easier for you to upgrade to future releases of FreeBSD.

To actually select a subset of the sources, use the Custom menu item when you are in the Distributions menu of the system installation tool.

Building a new kernel was originally pretty much a required step in a FreeBSD installation, but more recent releases have benefited from the introduction of much friendlier kernel configuration methods. In 4.X and earlier, when at the FreeBSD boot prompt (boot:), use the -c flag and you will be dropped into a visual configuration screen which allows you to configure the kernel's settings for most common ISA cards. In FreeBSD 5.X and later this has been replaced by much more flexible "hints" which can be set from the loader prompt.

It may still be worthwhile building a new kernel containing just the drivers that you need, just to save a bit of RAM, but it is no longer necessary for most systems.

The default password format on FreeBSD is to use MD5-based passwords. These are believed to be more secure than the traditional UNIX password format, which used a scheme based on the DES algorithm. DES passwords are still available if you need to share your password file with legacy operating systems which still use the less secure password format (they are available if you choose to install the “crypto” distribution in sysinstall, or by installing the crypto sources if building from source). Installing the crypto libraries will also allow you to use the Blowfish password format, which is more secure. Which password format to use for new passwords is controlled by the “passwd_format” login capability in /etc/login.conf, which takes values of “des”, “blf” (if these are available) or “md5”. See the login.conf(5) manual page for more information about login capabilities.

If you have a IDE Zip® or Jaz® drive installed, remove it and try again. The boot floppy can get confused by the drives. After the system is installed you can reconnect the drive. Hopefully this will be fixed in a later release.

This error comes from confusion between the boot block's and the kernel's understanding of the disk devices. The error usually manifests on two-disk IDE systems, with the hard disks arranged as the master or single device on separate IDE controllers, with FreeBSD installed on the secondary IDE controller. The boot blocks think the system is installed on ad0 (the second BIOS disk) while the kernel assigns the first disk on the secondary controller device, ad2. After the device probing, the kernel tries to mount what the boot blocks think is the boot disk, ad0, while it is really ad2, and fails.

To fix the problem, do one of the following:

1. Reboot the system and hit Enter at the Booting kernel in 10 seconds; hit [Enter] to interrupt prompt. This will drop you into the boot loader.

   Then type set root_disk_unit="disk_number" . disk_number will be 0 if FreeBSD is installed on the master drive on the first IDE controller, 1 if it is installed on the slave on the first IDE controller, 2 if it is installed on the master of the second IDE controller, and 3 if it is installed on the slave of the second IDE controller.

   Then type boot, and your system should boot correctly.

   To make this change permanent (ie so you do not have to do this every time you reboot or turn on your FreeBSD machine), put the line root_disk_unit="disk_number" in /boot/loader.conf.local .

2. Move the FreeBSD disk onto the primary IDE controller, so the hard disks are consecutive.

The limit is 4 gigabytes on a standard i386 install. Beginning with FreeBSD versions 4.9 and 5.1, more memory can be supported through pae(4). This does require a kernel recompile, with an extra option to enable PAE:

options       PAE

FreeBSD/pc98 has a limit of 4 GB memory, and PAE can not be used with it. On FreeBSD/alpha, the limit on memory depends on the type of hardware in use - consult the Alpha Hardware Release Notes for details. Other architectures supported by FreeBSD have much higher theoretical limits on maximum memory (many terabytes).

For ffs filesystems, the maximum theoretical limit is 8 terabytes (2G blocks), or 16TB for the default block size of 8K. In practice, there is a soft limit of 1 terabyte, but with modifications filesystems with 4 terabytes are possible (and exist).

The maximum size of a single ffs file is approximately 1G blocks, or 4TB with a block size of 4K.

When the fs block size is 4K, triple indirect blocks work and everything should be limited by the maximum fs block number that can be represented using triple indirect blocks (approx. 1K^3 + 1K^2 + 1K), but everything is limited by a (wrong) limit of 1G-1 on fs block numbers. The limit on fs block numbers should be 2G-1. There are some bugs for fs block numbers near 2G-1, but such block numbers are unreachable when the fs block size is 4K.

For block sizes of 8K and larger, everything should be limited by the 2G-1 limit on fs block numbers, but is actually limited by the 1G-1 limit on fs block numbers. Using the correct limit of 2G-1 blocks does cause problems.

Because your world and kernel are out of synch. This is not supported. Be sure you use make buildworld and make buildkernel to update your kernel.

You can boot by specifying the kernel directly at the second stage, pressing any key when the | shows up before loader is started.

A “security profile” is a set of configuration options that attempts to achieve the desired ratio of security to convenience by enabling and disabling certain programs and other settings. For full details, see the Security Profile section of the Handbook's post-install chapter.