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Linear Network Coding, a type of erasure correcting code across networks instead of point-to-point links; Long code; Low-density parity-check code, also known as Gallager code, as the archetype for sparse graph codes; LT code, which is a near-optimal rateless erasure correcting code (Fountain code) m of n codes
DRAM memory may provide increased protection against soft errors by relying on error-correcting codes. Such error-correcting memory, known as ECC or EDAC-protected memory, is particularly desirable for highly fault-tolerant applications, such as servers, as well as deep-space applications due to increased radiation.
A code with this ability to reconstruct the original message in the presence of errors is known as an error-correcting code. This triple repetition code is a Hamming code with m = 2, since there are two parity bits, and 2 2 − 2 − 1 = 1 data bit.
Dynamic random-access memory (DRAM) may provide stronger protection against soft errors by relying on error-correcting codes. Such error-correcting memory, known as ECC or EDAC-protected memory, is particularly desirable for mission-critical applications, such as scientific computing, financial, medical, etc. as well as extraterrestrial ...
LDPC codes functionally are defined by a sparse parity-check matrix. This sparse matrix is often randomly generated, subject to the sparsity constraints—LDPC code construction is discussed later. These codes were first designed by Robert Gallager in 1960. [5] Below is a graph fragment of an example LDPC code using Forney's factor graph notation.
Reed–Solomon codes are able to detect and correct multiple symbol errors. By adding t = n − k check symbols to the data, a Reed–Solomon code can detect (but not correct) any combination of up to t erroneous symbols, or locate and correct up to ⌊t/2⌋ erroneous symbols at unknown locations.
Typical implementations use more advanced codes, such as a BCH code, that can correct multiple bits with less overhead. Chipkill is frequently combined with dynamic bit-steering , so that if a chip fails (or has exceeded a threshold of bit errors), another, spare, memory chip is used to replace the failed chip.
Memory scrubbing consists of reading from each computer memory location, correcting bit errors (if any) with an error-correcting code , and writing the corrected data back to the same location. [ 1 ] Due to the high integration density of modern computer memory chips , the individual memory cell structures became small enough to be vulnerable ...