Run Length Limited - definitie. Wat is Run Length Limited
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Wat (wie) is Run Length Limited - definitie

CODING TECHNIQUE IN COMMUNICATION TECHNOLOGY
Runlength-limited code; RLL interface; Run Length Limited; Run length limited; RLL (encoding); Run-length limited encoding; Run-length limited code; Run length limited encoding; Run length limited code; RLL encoding; RLL code; Run-length limited coding; Run length limited coding; RLL coding
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Run-length limited         
Run-length limited or RLL coding is a line coding technique that is used to send arbitrary data over a communications channel with bandwidth limits. RLL codes are defined by four main parameters: m, n, d, k.
Run Length Limited         
<storage> (RLL) The most popular scheme for encoding data on magnetic disks. RLL packs up to 50% more data on a disk than MFM. IBM invented RLL encoding and used it in mainframe disk drives. During the late 1980s, PC hard disks began using RLL. Today, virtually every drive on the market uses some form of RLL. Groups of bits are mapped to specific patterns of flux. The density of flux transitions is limited by the spatial resolution of the disk and frequency response of the head and electronics. However, transitions must be close enough to allow reliable clock recovery. RLL implementations vary according to the minimum and maximum allowed numbers of transition cells between transitions. For example, the most common variant today, RLL 1,7, can have a transition in every other cell and must have at least one transition every seven cells. The exact mapping from bits to transitions is essentially arbitrary. Other schemes include GCR, FM, {Modified Frequency Modulation} (MFM). See also: PRML. http://cma.zdnet.com/book/upgraderepair/ch14/ch14.htm. (2003-08-12)
Run-length encoding         
SIMPLE FORM OF DATA COMPRESSION IN WHICH RUNS OF DATA (SEQUENCES IN WHICH THE SAME DATA VALUE OCCURS IN MANY CONSECUTIVE DATA ELEMENTS) ARE STORED AS A SINGLE DATA VALUE AND COUNT
Run-length coded; Run length encoding; RLE Compression; .rle; Run-length; Run length; Run length coding; Run-length coding; T.45 (standard)
Run-length encoding (RLE) is a form of lossless data compression in which runs of data (sequences in which the same data value occurs in many consecutive data elements) are stored as a single data value and count, rather than as the original run. This is most efficient on data that contains many such runs, for example, simple graphic images such as icons, line drawings, Conway's Game of Life, and animations.

Wikipedia

Run-length limited

Run-length limited or RLL coding is a line coding technique that is used to send arbitrary data over a communications channel with bandwidth limits. RLL codes are defined by four main parameters: m, n, d, k. The first two, m/n, refer to the rate of the code, while the remaining two specify the minimal d and maximal k number of zeroes between consecutive ones. This is used in both telecommunication and storage systems that move a medium past a fixed recording head.

Specifically, RLL bounds the length of stretches (runs) of repeated bits during which the signal does not change. If the runs are too long, clock recovery is difficult; if they are too short, the high frequencies might be attenuated by the communications channel. By modulating the data, RLL reduces the timing uncertainty in decoding the stored data, which would lead to the possible erroneous insertion or removal of bits when reading the data back. This mechanism ensures that the boundaries between bits can always be accurately found (preventing bit slip), while efficiently using the media to reliably store the maximal amount of data in a given space.

Early disk drives used very simple encoding schemes, such as RLL (0,1) FM code, followed by RLL (1,3) MFM code, which were widely used in hard disk drives until the mid-1980s and are still used in digital optical discs such as CD, DVD, MD, Hi-MD and Blu-ray. Higher-density RLL (2,7) and RLL (1,7) codes became the de facto industry standard for hard disks by the early 1990s.