Arch 2d
Magnhild Mongolo
Currently we have official packages optimized for the x86-64 architecture. We complement our official package sets with a community-operated package repository that grows in size and quality each and every day.
Our strong community is diverse and helpful, and we pride ourselves on the range of skillsets and uses for Arch that stem from it. Please check out our forums and mailing lists to get your feet wet. Also glance through our wiki if you want to learn more about Arch.
After upgrading to openssh-9.8p1, the existing SSH daemon will be unable to accept new connections (see -/issues/5).
When upgrading remote hosts, please make sure to restart the sshd serviceusing systemctl try-restart sshd right after upgrading.
The role of of the project lead within Arch Linux is connected to a fewresponsibilities regarding decision making (when no consensus can be reached), handlingfinancial matters with SPI and overall project management tasks.
This change should help address performance, crash or start-up issues for a number of memory intensive applications, particularly for (but not limited to) some Windows games played through Wine/Steam Proton. Overall, end users should have a smoother experience out of the box with no expressed concerns about potential downsides in the related proposal on arch-dev-public mailing list.
Update: To our knowledge the malicious code which was distributed viathe release tarball never made it into the Arch Linux provided binaries,as the build script was configured to only inject the bad code inDebian/Fedora based package build environments. The news item below cantherefore mostly be ignored.
With the release of mkinitcpio v38, several hooks previously provided by Arch packages have beenmoved to the mkinitcpio upstream project. The hooks are: systemd, udev, encrypt,sd-encrypt, lvm2 and mdadm_udev.
As a prefix, arch- appears in a number of titles referring to positions of superiority, such as archduke and archbishop; it can also mean "chief" (as in archnemesis) or "extreme" (archconservative). It comes from the Greek verb archein, meaning "to begin or to rule."
An arch is a curved vertical structure spanning an open space underneath it.[1] Arches may support the load above them, or they may perform a purely decorative role. As a decorative element, the arch dates back to the 4th millennium BC, but structural load-bearing arches became popular only after their adoption by the Ancient Romans in the 4th century BC.[2]
Arch-like structures can be horizontal, like an arch dam that withstands the horizontal hydrostatic pressure load.[3] Arches are normally used as supports for many types of vaults, with the barrel vault in particular being a continuous arch.[4] Extensive use of arches and vaults characterizes an arcuated construction, as opposed to the trabeated system, where, like in the architectures of ancient Greece, China, and Japan (as well as the modern steel-framed technique), posts and beams dominate.[5]
Arches had several advantages over the lintel, especially in the masonry construction: with the same amount of material it can have larger span, carry more weight, and can be made from smaller and thus more manageable pieces.[6] Their role in construction was diminished in the middle of the 19th century with introduction of the wrought iron (and later steel): the high tensile strength of these new materials made long lintels possible.
A true arch is a load-bearing arc with elements held together by compression.[7] In much of the world introduction of the true arch was a result of European influence.[2] The term false arch has few meanings. It is usually used to designate an arch that has no structural purpose, like a proscenium arch in theaters used to frame the performance for the spectators, but is also applied to corbelled and triangular arches that are not based on compression.[8][9]
A (left or right) half-segment of an arch is called an arc, the overall line of an arch is arcature[18] (this term is also used for an arcade).[19] Archivolt is the exposed (front-facing) part of the arch, sometimes decorated (occasionally also used to designate the intrados).[20] If the sides of voussoir blocks are not straight, but include angles and curves for interlocking, the arch is called "joggled".[21]
A true arch, due to its rise, resolves the vertical loads into horizontal and vertical reactions at the ends, a so called arch action. The vertical load produces a positive bending moment in the arch, while the inward-directed horizontal reaction from the spandrel/abutment provides a counterbalancing negative moment. As a result, the bending moment in any segment of the arch is much smaller than in a beam with the equivalent load and span.[22] The diagram on the right shows the difference between a loaded arch and a beam. Elements of the arch are mostly subject to compression (A), while in the beam a bending moment is present, with compression at the top and tension at the bottom (B).
In the past, when arches were made of masonry pieces, the horizontal forces at the ends of an arch caused the need for heavy abutments (cf. Roman triumphal arch). The other way to counteract the forces, and thus allow thinner supports, was to use the counter-arches, as in an arcade arrangement, where the horizontal thrust of each arch is counterbalanced by its neighbors, and only the end arches need to buttressed. With new construction materials (steel, concrete, engineered wood), not only the arches themselves got lighter, but the horizontal thrust can be further relieved by a tie connecting the ends of an arch.[6]
When evaluated from the perspective of an amount of material required to support a given load, the best solid structures are compression-only; with the flexible materials, the same is true for tension-only designs. There is a fundamental symmetry in nature between solid compression-only and flexible tension-only arrangements, noticed by Robert Hooke in 1676: "As hangs the flexible line, so but inverted will stand the rigid arch", thus the study (and terminology) of arch shapes is inextricably linked to the study of hanging chains, the corresponding curves or polygons are called funicular. Just like the shape of a hanging chain will vary depending on the weights attached to it, the shape of an ideal (compression-only) arch will depend on the distribution of the load. [23]
A sequence of arches can be grouped together forming an arcade. Romans perfected this form, as shown, for example, by arched structures of Pont du Gard.[28] In the interior of hall churches, arcades of separating arches were used to separate the nave of a church from the side aisle,[29] or two adjacent side aisles.[30]
An opening of the arch can be filled, creating a blind arch. Blind arches are frequently decorative, and were extensively used in Early Christian, Romanesque, and Islamic architecture.[32] Alternatively, the opening can be filled with smaller arches, producing a containing arch, common in Gothic and Romanesque architecture.[33] Multiple arches can be superimposed with an offset, creating an interlaced series of usually (with some exceptions) blind and decorative arches. Most likely of Islamic origin, the interlaced arcades were popular in Romanesque and Gothic architecture.[34] Rear-arch (also rere-arch) is the one that frames the internal side of an opening in the external wall.[35]
Structurally, relieving arches (often blind or containing) can be used to take off load from some portions of the building (for example, to allow use of thinner exterior walls with larger window openings, or, as in the Roman Pantheon, to redirect the weight of the upper structures to particular strong points).[33] Transverse arches, introduced in Carolingian architecture, are placed across the nave to compartmentalize (together with longitudinal separating arches) the internal space into bays and support vaults.[36] A diaphragm arch similarly goes in the transverse direction, but carries a section of wall on top. It is used to support or divide sections of the high roof.[37] Strainer arches were built as an afterthought to prevent two adjacent supports from imploding due to miscalculation. Frequently they were made very decorative, with one of the best examples provided by the Wells Cathedral. Strainer arches can be "inverted" (upside-down) while remaining structural.[38][39] When used across railway cuttings to prevent collapse of the walls, strainer arches may be referred to as flying arches.[40][41] A counter-arch is built adjacent to another arch to oppose its horizontal action or help to stabilize it, for example, when constructing a flying buttress.[42]
"Round" semicircular arches were commonly used for ancient arches that were constructed of heavy masonry,[44] and were relied heavily on by the Roman builders since the 4th century BC. It is considered to be the most common arch form,[45] characteristic for Roman, Romanesque, and Renaissance architecture.[25]
A segmental arch, with a rounded shape that is less than a semicircle, is very old (the versions were cut in the rock in Ancient Egypt c. 2100 BC at Beni Hasan). Since then it was occasionally used in Greek temples,[46] utilized in Roman residential construction,[47] Islamic architecture, and got popular as window pediments during the Renaissance.[46]
A basket-handle arch (also known as depressed arch, three-centred arch, basket arch) consists of segments of three circles with origins at three different centers (sometimes uses five or seven segments, so can also be five-centred, etc.). Was used in late Gothic and Baroque architecture.[48][49]
A horseshoe arch (also known as keyhole arch) has a rounded shape that includes more than a semicircle, is associated with Islamic architecture and was known in areas of Europe with Islamic influence (Spain, Southern France, Italy). Occasionally used in Gothics, it briefly enjoyed popularity as the entrance door treatment in the interwar England.[50]
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