Some operating systems, such as OpenBSD with its W ^ X feature, and Linux with the Exec Shield or PaX patches, may also limit the length of the code segment, as specified by the CS register, to disallow execution of code in modifiable regions of the address space.

On some systems, the page fault mechanism is also used for executable space protection such as W ^ X.

Prior to the onset of this feature within the hardware, various operating systems attempted to emulate this feature through software, such as W ^ X or Exec Shield.

In Mac OS X 10. 5, all 64-bit executables have NX stack and heap ; W ^ X protection.

A technology in the OpenBSD operating system, known as W ^ X, marks writable pages by default as non-executable on processors that support that.

W ^ X makes use of the NX bit on Alpha, AMD64, HPPA, and SPARC processors.

OpenBSD 3. 3 shipped May 1, 2003, and was the first operating system to include W ^ X.

This change is similar to the Exec Shield NX implementation, and the OpenBSD W ^ X implementation ; except that PaX uses the Supervisor bit overloading method to handle NX pages in the code segment as well.

* W ^ X

OpenBSD also supplies an executable space protection scheme known as W ^ X ( memory is writable xor executable ), as well as a ProPolice compiled executable base.

Values of power density in crossover ( focus ) of the beam as high as 10 ^ 4 – 10 ^ 6 W / mm ^ 2 can be achieved.

* W ^ X

* Comparison of PaX to Exec Shield and W ^ X

A more concise alternative sometimes seen is ^ W, which is the shortcut to delete the previous word in the Berkeley Unix terminal line discipline.

One ^ W can replace a whole string of ^ H's.

For really embarrassing blunders, ^ U ( kill line ) can outdo a series of ^ W.

W ^ X (" Write XOR Execute "; spoken as double-u ex-or ex ) is the name of a security feature present in the OpenBSD operating system.

W ^ X does not prevent these permissions from being requested by applications, write and executable permissions are not used as a matter of policy.

W ^ X first appeared in OpenBSD 3. 3, released May 2003.

W ^ X is relatively simple on processors which support fine-grained page permissions, such as Sun's SPARC and SPARC64, AMD's AMD64, Hewlett-Packard's PA-RISC, and HP's ( originally Digital Equipment Corporation's ) Alpha ; some early Intel 64 processors lacked the NX bit required for W ^ X, but this appeared in later chips.

: W, X, Y, Z

Let V, W and X be three vector spaces over the same base field F. A bilinear map is a function

: B: V × W → X

is a linear map from W to X.

The set L ( V, W ; X ) of all bilinear maps is a linear subspace of the space ( viz.

vector space, module ) of all maps from V × W into X.

Though the article was signed pseudonymously by " X ," it was well known at the time that the true author was George F. Kennan, the deputy chief of mission of the United States to the Soviet Union from 1944 to 1946, under ambassador W. Averell Harriman.

The 21 consonant letters in the English alphabet are B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, X, Z, and usually W and Y: The letter Y stands for the consonant in " yoke ", the vowel in " myth " and the vowel in " funny ", and " yummy " for both consonant and vowel, for examples ; W almost always represents a consonant except in rare words ( mostly loanwords from Welsh ) like " crwth " " cwm ".

For example, W, a witness, testifies that she saw X drive his automobile into a green car.

The bosons are found by adding a partner to each of the 20 charged bosons ( 2 right-handed W bosons, 6 massive charged gluons and 12 X / Y type bosons ) and adding an extra heavy neutral Z-boson to make 5 neutral bosons in total.

* Furek, Maxim W .: The Death Proclamation of Generation X: A Self-Fulfilling Prophesy of Goth, Grunge and Heroin ".

More unusual configurations such as the H, U, X, and W have also been used.

Tourmalines can be subgrouped by the occupancy of the X site, and from there further subdivided by the chemistry of the W site.

< center > A ( a ), B ( be ), C ( ce ), D ( de ), E ( e ), F ( ef ), G ( ge ), H ( ha ), I ( i ), J ( jot ), K ( ka ), L ( el ), M ( em ), N ( en ), O ( o ), P ( pe ), Q ( qu ), R ( er ), S ( es ), T ( te ), U ( u ), V ( ve ), W ( duplic ve ), X ( ix ), Y ( ypsilon ), Z ( zet )</ center >

The others, lettered I, T, U, V, W, and X, are equivalent to some rotation of their mirror images.

If rotations are also considered distinct, then the pentominoes from the first category count eightfold, the ones from the next three categories ( T, U, V, W, Z ) count fourfold, I counts twice, and X counts only once.

* Reduced form, in statistics, an equation which relates the endogenous variable X to all the available exogenous variables, both those included in the regression of interest ( W ) and the instruments ( Z )

The Australian letter to number mapping was: A = 1, B = 2, F = 3, J = 4, L = 5, M = 6, U = 7, W = 8, X = 9, Y = 0, so the phone number BX 3701 was in fact 29 3701.

Like the " dimension of image " characterization this can be generalized to a definition of the rank of a linear map: the rank of a linear map f from V → W is the minimal dimension k of an intermediate space X such that f can be written as the composition of a map V → X and a map X → W. While this definition does not suggest an efficient manner to compute the rank ( for which it is better to use one of the alternative definitions ), it does allow to easily understand many of the properties of the rank, for instance that the rank of the transpose of A is the same as that of A.

The team, captained by W G Grace, is organised by Lord Sheffield who later subscribes his Sheffield Shield to Australian domestic first-class cricket.

However, William Wordsworth employed rhyme royal ( slightly modified by an alexandrine in the seventh line ) in " Resolution and Independence ", and notable twentieth-century poems in the stanza are W. H. Auden's Letter to Lord Byron ( as well as some of the stanzas in The Shield of Achilles ) and W. B. Yeats's A Bronze Head.

* SLAMS ( Space Land Air Missile Shield ), a fictional anti-ballistic missile system from Tom Clancy's H. A. W. X.

* Robin Hood, or Sherwood Forest ( 10. 3. 1794 Philadelphia ) ( W. Shield )

) In Butt, Archibald W. Both Sides of the Shield.

" In Butt, Archibald W. Both Sides of the Shield.