HURD

Date "HURD" was first used in popular English literature: sometime before 1791. (references)

"HURD" is a common misspelling or typo for: hard, herd, hued, hurl, hurt.

Specialty Definition: HURD

Domain	Definition
Computing	Hurd The Hurd will be the foundation of the whole GNU system. It is built on top of the Mach 3.0 kernel, a free message-passing kernel developed by CMU. Mach's virtual memory management and message-passing facilities are extensively used by the Hurd. The GNU C Library will provide the Unix system call interface, and will call the Hurd for needed services it can't provide itself. One goal of the Hurd is to establish a framework for shared development and maintenance. The Hurd is like GNU Emacs in that it will allow a broad range of users to create and share useful projects without knowing much about the internal workings of the system -- projects that might never have been attempted without freely available source, a well-designed interface, and a multi-server-based design. Currently there are free ports of the Mach kernel to the Intel 80386 IBM PC, the DEC PMAX workstation, the Luna 88k and several other machines, with more in progress, including the Amiga and DEC Alpha-3000 machines. Contact , if you want to help with one of these or start your own. Porting the GNU Hurd and GNU C Library is easy (easier than porting GNU Emacs, certainly easier than porting GCC) once a Mach port to a particular platform exists. [June 1994 GNU's Bulletin]. (1994-12-07). Source: The Free On-line Dictionary of Computing.
Source: compiled by the editor from various references; see credits.

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Specialty Definition: Hurd

(From Wikipedia, the free Encyclopedia)

In computing, the Hurd is a Unix-like kernel that sets the base for the GNU operating system. It's being developed by the GNU Project as free software under the GPL license. The Hurd aims for surpassing Unix kernels in capability, while remaining largely compatible with them. This is done by having the Hurd track the POSIX specification, but avoiding arbitrary restrictions on the user.

Architecture

Unlike most Unix-like kernels, the Hurd builds on top of a microkernel which is responsible for providing the most basic kernel services – coordinating access to the hardware: the CPU (through multiprocessing), RAM (via memory management), and other various devices for sound, graphics, mass storage, etc. Currently GNU Mach is used as the microkernel, but efforts are underway to port the Hurd to other microkernels such as L4.

There are other Unix-like systems running on top of the Mach kernel, including OSF/1, NeXTSTEP, Mac OS X, Lites, and MkLinux. These share one detail in common, in that they are implemented as a single so called server. In effect they replace the monolithic kernel from a traditional Unix system with two parts, the microkernel and Unix server.

The Hurd instead consists of multiple servers working together. Instead of a single large code base which includes everything from handling the clock to handling the networking, in the Hurd each of these are handled by a separate server. This makes developing the Hurd much easier (at least in theory) as making changes to one is less likely to have side-effectss in others. This explains the mutually recursive acronym: "Hurd" stands for "Hird of Unix-Replacing Dæmons", and "Hird" stands for "Hurd of Interfaces Representing Depth".

In the original Mach efforts this sort of "set of servers" was considered to be one of the main goals of the design, but the Hurd appears to be the first Mach-based system core to actually be implemented in this fashion (whereas QNX is similar but based on its own microkernel). It's not entirely clear why this happened, but it appears that groups working on Mach were too busy working on Mach to work on the operating system as a whole.

Unix extensions

A number of traditional Unix concepts are replaced or extended in the Hurd:

Under Unix every program running has an associated user id, which normally corresponds to the user that started the process. This id largely dictates the action permitted to the program. No outside process can change the user id of a running program. A Hurd process, on the other hand, runs under a set of user ids, which can contain multiple ids, one, or none. A sufficiently privileged process can add and remove ids to another process. For example there is a password server that will hand out ids in return for a correct login password.

Regarding the filesystem, a suitable program can be designated as a translator for a single file or a whole directory hierarchy. Every access to the translated file, or files below a hierarchy in the second case, is in fact handled by the program. For example a file translator may simply redirect read and write operations to another file, not unlike a Unix symbolic link. What mounting is to Unix, the Hurd achieves by setting up a filesystem translator. Translators can also be used to provide services to the user. For example, the ftpfs translator allows a user to encapsulate remote FTP sites within a directory. Then, standard tools such as ls, cp, and rm can be used to manipulate files on the remote system. Even more powerful translators are ones such as shadowfs, which allows a user to shadow multiple directories into one; so that listing the shadowed directory reveals the contents of all the shadowed directories (a major missing feature in Unix).

Perhaps the most empowering aspect of the Hurd is the ability for any user to start their own system services. Any user can attach any translator to the filesystem for his own personal use. A user could even replace system servers, such as the auth server, with other servers of his own choosing. All this can be done without affecting other users, due to well defined scopes. Indeed, it is even possible for a user to run the Hurd within itself, which is known as a sub-Hurd.

The Hurd requires a multiboot-compliant bootloader, such as GRUB.

Development history

At this time, there is a single distribution of a Hurd-based GNU system in preparation, which has not yet been officially released outside of interested testers and developers. That distribution is Debian GNU/Hurd. Richard Stallman, of the GNU project, had announced that he expected the GNU OS (also known as GNU/Hurd) to be officially released before the end of 2002, but this was not achieved.

As of 2003, the Hurd has slow development and has major hardware limitations (eg the lack of sound support and a former lack of support for partitionss larger than approximately 1.5 gigabytes.) Thanks to increasing support from the Debian project and others, these limitations are well on the way to being beaten and once they do, it is expected to be a very functional kernel for the GNU system.

External links

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Hurd."

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Abbreviations & Acronyms: HURD

The following table is compiled from various sources, across various languages. When English abbreviations or acronyms come from a non-English source, this is noted.
Entry	Source	Expression	Field
HURD	English	HIRD of Unix-Replacing DAEMONs	Computer - (GNU, HIRD)
Source: compiled by the editor, based on several corpora (additional references).

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Crosswords: HURD

Specialty definitions using "HURD": Debian GNU/Hurd ♦ Linux. (references)

Non-English Usage: "HURD" is also a word in the following language with the English translation in parentheses.

Frisian (hard).

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Commercial Usage: HURD

Domain	Title
Books	A Bibiography of Richard Hurd (reference) My Land Is the Southwest: Peter Hurd Letters and Journals (reference) Peter Hurd (reference) The David Hurd Hymnary: Twenty-Nine New Hymn Tunes With Various Texts (reference) The Public Servant - The Authorized Biography of Douglas Hurd (reference) (more book examples)

Music	Minister Stephen A. Hurd & Corporate Worship, Vol. 1 (reference) (more classical music examples; more popular music examples)
Source: compiled by the editor from various references; see credits.

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Photo Album: HURD

Thumbnail	Description & Credit	Thumbnail	Description & Credit
	NRCS employee Kerry Perkins, and Ted Smidt and landowner Al Moore observing progress of conservation plan on Hurd Creek, Washington. Credit: Gary Wilson.		Ted Smidt monitoring stream temperature along the Hurd Creek, Washington, near Port Angeles. Credit: Gary Wilson.
	Landowner, Al Moore, observing wildlife in pond on Hurd Creek, Washington. Credit: Gary Wilson.		Structures in Hurd creek, Washington. J-hooks are used to help stabilize the stream and prevent further stream bank erosion. Credit: Gary Wilson.
	Henry M. Hurd / P. Credit: National Library of Medicine; photo by Bachrach..		Passenger boats on the Mississippi, Clinton, Iowa / C.L. Hurd, publ. Credit: Library of Congress.
	Keedysville, Md., vicinity. Confederate wounded at Smith's Barn, with Dr. Anson Hurd, 14th Indiana Volunteers, in attendance. Credit: Library of Congress.		High school girls learn the art of automobile mechanics. Left to right: Grace Hurd, Evelyn Harrison, and Corinna DiJiulian, with Grace Wagner (under car), at Central High, Wash. D.C. Credit: Library of Congress.
	Portrait of Hurd Hatfield, as Lord Byron in Camino Real. Credit: Library of Congress.
Source: pictures compiled by the editor from various references; see picture credits.

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Usage Frequency: HURD

"HURD" is generally used as a noun (proper) -- approximately 99.69% of the time. "HURD" is used about 654 times out of a sample of 100 million words spoken or written in English. Its rank is based on over 700,000 words used in the English language. Some parts-of-speech are not covered due to the samples used by the British National Corpus. (note: percents less than one-hundredth of one percent have been omitted)

Parts of Speech	Percent	Usage per 100 Million Words	Rank in English
Noun (proper)	99.69%	652	10,033
Noun (singular)	0.31%	2	245,945
Total	100.00%	654	N/A

Source: compiled by the editor from several corpora; see credits.

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Name Usage Frequency: HURD

The following table summarizes the usage of "HURD" based on a population census conducted in the United States. Ranks and frequencies are based on all names reported and classified.

Name	Usage/Gender	Usage per 100 million Persons	Rank in USA
Hurd	Last name	8,000	1,490
Source: compiled by the editor from several corpora; see credits.

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Expression: HURD

Hyphenated Usage
	Beginning with "HURD": hurd-major.
Source: compiled by the editor from various references; see credits.

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Frequency of Internet Keywords: HURD

The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com.

Expression	Frequency per Day	Expression	Frequency per Day
hurd window	140	co hurd millwork	4
hurd	57	hurd paige	4
hurd rachel wood	28	dontae hurd	4
peter hurd	22	hurd bob	4
gale anne hurd	11	dr hurd	4
gnu hurd	10	bill hurd	3
door hurd	9	hurd mark	3
hurd chevrolet	9	ann gale hurd	3
hurd michelle	8	michael hurd	3
hurd stephen	7	hurd lock	3
hurd weston	7	david hurd	3
hurd millwork	6	hurd stadium	3
artist hurd michael	6	artist hurd peter	3
hurd buick	6	hurd supercaster	3
hurd orchard	6	estate hurd real	2
hurd hatfield	6	clement hurd	2
door hurd window	6	cornell hurd	2
john hurd	5	bill hurd chevrolet	2
debra hurd	5	ellen hurd	2
gmc hurd	4	hurd part window	2
Source: compiled by the editor from various references; see credits.

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Derivations: HURD

Derivations
	Words beginning with "HURD": hurdies, hurdle, hurdled, hurdler, hurdlers, hurdles, hurdling, hurds. (additional references)
Source: compiled by the editor, based on several corpora (additional references).

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Anagrams: HURD

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "d-h-r-u"
	-1 letter: duh, urd.
	-2 letters: uh.
	Words containing the letters "d-h-r-u"
	+1 letter: hurds.
	+2 letters: dhurna, dourah, drouth, hurdle, hurled, purdah, ruched, rushed, shroud.
	+3 letters: bahadur, brushed, chuddar, chudder, churned, churred, crushed, dhourra, dhurnas, dhurrie, dourahs, draught, drought, drouths, drouthy, euchred, hirudin, hounder, huddler, humdrum, humidor, humored, hundred, hurdies, hurdled, hurdler, hurdles, hurried, hurtled, hydrous, jodhpur, lurched, prudish, purdahs, pushrod, rhodium, roughed, shrouds, shudder, thunder, unheard, unhired, uphoard, ushered.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.