21-letter words containing f, e, l, m
- universal disk format — (storage, standard) (UDF) A CD-ROM file system standard that is required for DVD ROMs. UDF is the OSTA's replacement for the ISO 9660 file system used on CD-ROMs, but will be mostly used on DVD. DVD multimedia disks use UDF to contain MPEG audio and video streams. To read DVDs you need a DVD drive, the kernel driver for the drive, MPEG video support, and a UDF driver. DVDs containing both UDF filesystems and ISO 9660 filesystems can be read without UDF support. UDF can also be used by CD-R and CD-RW recorders in packet writing mode.
- until the end of time — If you say that something will happen or be true until the end of time or to the end of time, you are emphasizing that it will always happen or always be true.
- volumetric efficiency — the ratio of fluid delivered by a piston or ram pump per stroke to the displacement volume of the piston or ram
- volunteers of america — a religious reform and relief organization, similar to the Salvation Army, founded in New York City in 1896 by Ballington Booth, son of William Booth, the founder of the Salvation Army. Abbreviation: VOA.
- warm silence software — A small company run by(?) Robin Watts, producing software for the Acorn Archimedes.
- weak head normal form — (reduction, theory) (WHNF) A lambda expression is in weak head normal form (WHNF) if it is a head normal form (HNF) or any lambda abstraction. I.e. the top level is not a redex. The term was coined by Simon Peyton Jones to make explicit the difference between head normal form (HNF) and what graph reduction systems produce in practice. A lambda abstraction with a reducible body, e.g. \ x . ((\ y . y+x) 2) is in WHNF but not HNF. To reduce this expression to HNF would require reduction of the lambda body: (\ y . y+x) 2 --> 2+x Reduction to WHNF avoids the name capture problem with its need for alpha conversion of an inner lambda abstraction and so is preferred in practical graph reduction systems. The same principle is often used in strict languages such as Scheme to provide call-by-name evaluation by wrapping an expression in a lambda abstraction with no arguments: D = delay E = \ () . E The value of the expression is obtained by applying it to the empty argument list:
- william of malmesbury — William of, William of Malmesbury.
- xilinx netlist format — (language, electronics) (XNF) A Hardware Description Language for electronic circuit design, developed by Xilinx, Inc..
- yellow-fever mosquito — a mosquito, Aedes aegypti, that transmits yellow fever and dengue.