This glossary contains terms and acronyms used within the FreeBSD community and documentation.
See: Access Control List
See: ACPI Source Language
Pseudocode, interpreted by a virtual machine within an ACPI-compliant operating system, providing a layer between the underlying hardware and the documented interface presented to the OS.
The programming language AML is written in.
A specification which provides an abstraction of the interface the hardware presents to the operating system, so that the operating system should need to know nothing about the underlying hardware to make the most of it. ACPI evolves and supercedes the functionality provided previously by APM, PNPBIOS and other technologies, and provides facilities for controlling power consumption, machine suspension, device enabling and disabling, etc.
A set of procedures, protocols and tools that specify the canonical interaction of one or more program parts; how, when and why they do work together, and what data they share or operate on.
A daemon that automatically mounts a filesystem when a file or directory within that filesystem is accessed.
The registers that determine which address range a PCI device will respond to.
The definition of BIOS depends a bit on the context. Some people refer to it as the ROM chip with a basic set of routines to provide an interface between software and hardware. Others refer to it as the set of routines contained in the chip that help in bootstrapping the system. Some might also refer to it as the screen used to configure the boostrapping process. The BIOS is PC-specific but other systems have something similar.
An implementation of the DNS protocols.
This is the name that the Computer Systems Research Group (CSRG) at The University of California at Berkeley gave to their improvements and modifications to AT&T's 32V UNIX®. FreeBSD is a descendant of the CSRG work.
A phenomenon whereby many people will give an opinion on an uncomplicated topic, whilst a complex topic receives little or no discussion. See the FAQ for the origin of the term.
See: Carrier Detect
See: Clear To Send
An RS232C signal indicating that a carrier has been detected.
Also known as the processor. This is the brain of the computer where all calculations take place. There are a number of different architectures with different instruction sets. Among the more well-known are the Intel-x86 and derivatives, Sun SPARC, PowerPC, and Alpha.
An RS232C signal giving the remote system permission to send data.
See: Debugger
See: Domain Name System
See: Data Set Ready
See: Data Terminal Ready
The system that converts humanly readable hostnames (i.e., mail.example.net) to Internet addresses and vice versa.
A protocol that dynamically assigns IP addresses to a computer (host) when it requests one from the server. The address assignment is called a “lease”.
See: Extended COFF
The name of a mutual exclusion mechanism (a sleep mutex) that protects a large set of kernel resources. Although a simple locking mechanism was adequate in the days where a machine might have only a few dozen processes, one networking card, and certainly only one processor, in current times it is an unacceptable performance bottleneck. FreeBSD developers are actively working to replace it with locks that protect individual resources, which will allow a much greater degree of parallelism for both single-processor and multi-processor machines.
A system where the user and computer interact with graphics.
See: HangUp
The markup language used to create web pages.
See: Input/Output
See: Intel's ASL compiler
See: Internet Protocol
See: IP Firewall
See: IP Version 4
See: IP Version 6
The IP protocol version 4, which uses 32 bits for addressing. This version is still the most widely used, but it is slowly being replaced with IPv6.
See Also: IP Version 6.
The new IP protocol. Invented because the address space in IPv4 is running out. Uses 128 bits for addressing.
Intel's compiler for converting ASL into AML.
The packet transmitting protocol that is the basic protocol on the Internet. Originally developed at the U.S. Department of Defense and an extremly important part of the TCP/IP stack. Without the Internet Protocol, the Internet would not have become what it is today. For more information, see RFC 791.
A company that provides access to the Internet.
Japanese for “turtle”, the term KAME is used in computing circles to refer to the KAME Project, who work on an implementation of IPv6.
See: Kilo Bits Per Second
A kernel-supported threading system. See the project home page for further details.
Used to measure bandwith (how much data can pass a given point at a specified amount of time). Alternates to the Kilo prefix include Mega, Giga, Tera, and so forth.
See: Local Area Network
See: Lock Order Reversal
See: Line Printer Daemon
A network used on a local area, e.g. office, home, or so forth.
The FreeBSD kernel uses a number of resource locks to arbitrate contention for those resources. A run-time lock diagnostic system found in FreeBSD-CURRENT kernels (but removed for releases), called witness(4), detects the potential for deadlocks due to locking errors. (witness(4) is actually slightly conservative, so it is possible to get false positives.) A true positive report indicates that “if you were unlucky, a deadlock would have happened here”.
True positive LORs tend to get fixed quickly, so check http://lists.FreeBSD.org/mailman/listinfo/freebsd-current and the LORs Seen page before posting to the mailing lists.
See: Merge From Current
See: Merge From Perforce
See: Merge From Stable
See: Multi-Level Security
See: Message Of The Day
See: Mail Transfer Agent
See: Mail User Agent
An application used to transfer email. An MTA has traditionally been part of the BSD base system. Today Sendmail is included in the base system, but there are many other MTAs, such as postfix, qmail and Exim.
An application used by users to display and write email.
To merge functionality or a patch from the -CURRENT branch to another, most often -STABLE.
To merge functionality or a patch from the Perforce repository to the -CURRENT branch.
See Also: Perforce.
In the normal course of FreeBSD development, a change will be committed to the -CURRENT branch for testing before being merged to -STABLE. On rare occasions, a change will go into -STABLE first and then be merged to -CURRENT.
This term is also used when a patch is merged from -STABLE to a security branch.
See Also: Merge From Current.
A message, usually shown on login, often used to distribute information to users of the system.
See: Project Evil
See: Network File System
A filesystem developed by Microsoft and available in its “New Technology” operating systems, such as Windows® 2000, Windows NT® and Windows XP.
See: Overtaken By Events
See: On-Demand Mail Relay
See: Operating System
A set of programs, libraries and tools that provide access to the hardware resources of a computer. Operating systems range today from simplistic designs that support only one program running at a time, accessing only one device to fully multi-user, multi-tasking and multi-process systems that can serve thousands of users simultaneously, each of them running dozens of different applications.
Indicates a suggested change (such as a Problem Report or a feature request) which is no longer relevant or applicable due to such things as later changes to FreeBSD, changes in networking standards, the affected hardware having since become obsolete, and so forth.
See: Perforce
See: Personal Computer
See: Process ID
See: Post Office Protocol
See: PPP over ATM
See: PPP over Ethernet
See: Problem Report
A source code control product made by Perforce Software which is more advanced than CVS. Although not open source, it use is free of charge to open-source projects such as FreeBSD.
Some FreeBSD developers use a Perforce repository as a staging area for code that is considered too experimental for the -CURRENT branch.
A method of enabling access to up to 64 GB of RAM on systems which only physically have a 32-bit wide address space (and would therefore be limited to 4 GB without PAE).
A mythical piece of headgear, much like a dunce cap, awarded to any FreeBSD committer who breaks the build, makes revision numbers go backwards, or creates any other kind of havoc in the source base. Any committer worth his or her salt will soon accumulate a large collection. The usage is (almost always?) humorous.
As FreeBSD evolves, changes visible to the user should be kept as unsurprising as possible. For example, arbitrarily rearranging system startup variables in /etc/defaults/rc.conf violates POLA. Developers consider POLA when contemplating user-visible system changes.
A description of some kind of problem that has been found in either the FreeBSD source or documentation. See Writing FreeBSD Problem Reports.
A number, unique to a particular process on a system, which identifies it and allows actions to be taken against it.
The working title for the NDISulator, written by Bill Paul, who named it referring to how awful it is (from a philosophical standpoint) to need to have something like this in the first place. The NDISulator is a special compatibility module to allow Microsoft Windows™ NDIS miniport network drivers to be used with FreeBSD/i386. This is usually the only way to use cards where the driver is closed-source. See src/sys/compat/ndis/subr_ndis.c.
See: Router Advertisement
See: Random Access Memory
See: Received Data
See: Request For Comments
See: Request To Send
A standard for communications between serial devices.
See: Repository Copy
A direct copying of files within the CVS repository.
Without a repocopy, if a file needed to be copied or moved to another place in the repository, the committer would run cvs add to put the file in its new location, and then cvs rm on the old file if the old copy was being removed.
The disadvantage of this method is that the history (i.e. the entries in the CVS logs) of the file would not be copied to the new location. As the FreeBSD Project considers this history very useful, a repository copy is often used instead. This is a process where one of the repository meisters will copy the files directly within the repository, rather than using the cvs(1) program.
A set of documents defining Internet standards, protocols, and so forth. See www.rfc-editor.org.
Also used as a general term when someone has a suggested change and wants feedback.
See: Signal Ground
See: Server Message Block
See: SMTP Authentication
See: Secure Shell
See: Suspend To RAM
An RS232 pin or wire that is the ground reference for the signal.
See: Transmitted Data
See: Trivial FTP
See: Time Stamp Counter
A profiling counter internal to modern Pentium® processors that counts core frequency clock ticks.
A protocol that sits on top of (e.g.) the IP protocol and guarantees that packets are delivered in a reliable, ordered, fashion.
The term for the combination of the TCP protocol running over the IP protocol. Much of the Internet runs over TCP/IP.
See: User ID
See: Universal Serial Bus
A unique number assigned to each user of a computer, by which the resources and permissions assigned to that user can be identified.
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