Error Correct
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computer data storage that can detect and correct the most common kinds of internal data corruption. ECC memory is used in most computers where data corruption cannot be tolerated under any circumstances, such as for scientific or error correction code financial computing. Typically, ECC memory maintains a memory system immune to single-bit errors: the error correction in english data that is read from each word is always the same as the data that had been written to it, even if one error detection and correction or more bits actually stored have been flipped to the wrong state. Most non-ECC memory cannot detect errors although some non-ECC memory with parity support allows detection but not correction. Contents 1 Problem background 2 Solutions
Error Detection And Correction In Computer Networks
3 Implementations 4 Cache 5 Registered memory 6 Advantages and disadvantages 7 References 8 External links Problem background[edit] Electrical or magnetic interference inside a computer system can cause a single bit of dynamic random-access memory (DRAM) to spontaneously flip to the opposite state. It was initially thought that this was mainly due to alpha particles emitted by contaminants in chip packaging material, but research has shown that the majority of one-off soft errors in error correction exercises DRAM chips occur as a result of background radiation, chiefly neutrons from cosmic ray secondaries, which may change the contents of one or more memory cells or interfere with the circuitry used to read or write to them.[2] Hence, the error rates increase rapidly with rising altitude; for example, compared to the sea level, the rate of neutron flux is 3.5 times higher at 1.5km and 300 times higher at 10–12km (the cruising altitude of commercial airplanes).[3] As a result, systems operating at high altitudes require special provision for reliability. As an example, the spacecraft Cassini–Huygens, launched in 1997, contains two identical flight recorders, each with 2.5gigabits of memory in the form of arrays of commercial DRAM chips. Thanks to built-in EDAC functionality, spacecraft's engineering telemetry reports the number of (correctable) single-bit-per-word errors and (uncorrectable) double-bit-per-word errors. During the first 2.5years of flight, the spacecraft reported a nearly constant single-bit error rate of about 280errors per day. However, on November 6, 1997, during the first month in space, the number of errors increased by more than a factor of four for that single day. This was attributed to a solar particle event that had been detected by the satellite GOES 9.[4] There was some concern that as DRAM density increases further, and thus the components on chips get smaller, w
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Error Detection And Correction In Data Link Layer
Luggage & Travel Gear Luxury Beauty Magazine Subscriptions Movies & TV Musical Instruments Office Products Patio, Lawn & Garden Pet Supplies Prime Pantry Software Sports & Outdoors https://en.wikipedia.org/wiki/ECC_memory Tools & Home Improvement Toys & Games Vehicles Video Games Wine Go Departments Hello. Sign inYour AccountSign inYour AccountTry PrimeListsCart0 Your Amazon.comToday's DealsGift Cards & RegistrySellHelp Kingston ValueRAM 8GB 1600MHz... $39.99 Hi, what does it mean "Non-ECC CL11"? and Why other similar products does not say that? [UPDATED] asked by MK on July 22, http://www.amazon.com/Non-ECC-CL11-other-similar-products/forum/Fx2TWLO1ZBTZ6D9/Tx1GCY05JMIDR3R/1?asin=B0089JIDUI 2013 The answer body is empty. Please add text to it. Sort: Most Helpful first | Newest first | Oldest first Showing 1-2 of 2 answers A "Short for Error-Correcting-Code memory, a type of memory that includesspecial circuitry for testing and accuracy of data as it passes in andout of memory."Most home computers use standard memory, while ECC memory is used forcommercial applications where data integrity is very critical.When buying memory, the only time you will see ECC mentioned is if thememory *is* ECC, not if it is *not* ECC. ECC memory is also moreexpensive since it has an extra memory chip and circuitry to do theerror correction. Basically, the CL tells you how many clock cycles it takes to perform an action, so the less the better. "Short for Error-Correcting-Code memory, a type of memory that includesspecial circuitry for testing and accuracy of data as it passes in andout of memory."Most home computers use standard memory, while ECC memory is used
computer data storage that can detect and correct the most common kinds of internal data corruption. ECC memory is https://en.wikipedia.org/wiki/ECC_memory used in most computers where data corruption cannot be tolerated under any circumstances, such as for scientific or financial computing. Typically, ECC memory maintains a memory system immune http://www.qrcode.com/en/about/error_correction.html to single-bit errors: the data that is read from each word is always the same as the data that had been written to it, even if one error detection or more bits actually stored have been flipped to the wrong state. Most non-ECC memory cannot detect errors although some non-ECC memory with parity support allows detection but not correction. Contents 1 Problem background 2 Solutions 3 Implementations 4 Cache 5 Registered memory 6 Advantages and disadvantages 7 References 8 External links Problem background[edit] Electrical or error detection and magnetic interference inside a computer system can cause a single bit of dynamic random-access memory (DRAM) to spontaneously flip to the opposite state. It was initially thought that this was mainly due to alpha particles emitted by contaminants in chip packaging material, but research has shown that the majority of one-off soft errors in DRAM chips occur as a result of background radiation, chiefly neutrons from cosmic ray secondaries, which may change the contents of one or more memory cells or interfere with the circuitry used to read or write to them.[2] Hence, the error rates increase rapidly with rising altitude; for example, compared to the sea level, the rate of neutron flux is 3.5 times higher at 1.5km and 300 times higher at 10–12km (the cruising altitude of commercial airplanes).[3] As a result, systems operating at high altitudes require special provision for reliability. As an example, the spacecraft Cassini–Huygens, launched in 1997, contains two identical flight recorders, each with 2.5gigabits of memory in the form
to the operating environment. Raising this level improves error correction capability but also increases the amount of data QR Code size. To select error correction level, various factors such as the operating environment and QR Code size need to be considered. Level Q or H may be selected for factory environment where QR Code get dirty, whereas Level L may be selected for clean environment with the large amount of data. Typically, Level M (15%) is most frequently selected. *Data restoration rate for total codewords (codeword is a unit that constructs the data area. One codeword of QR Code is equal to 8 bits.) Error Correction Feature The QR Code error correction feature is implemented by adding a Reed-Solomon Code*to the original data. The error correction capability depends on the amount of data to be corrected. For example, if there are 100 codewords of QR Code to be encoded,50 of which need to be corrected, 100 codewords of Reed-Solomon Code are required, as Reed-Solomon Code requires twice the amount of codewords to be corrected. In this case, the total codewords are 200, 50 of which can be corrected. Thus, the error correction rate for the total codewords is 25%. This corresponds to QR Code error correction Level Q. In the example above, the error correction rate for QR Code codewords can be considered as 50%. However, it is not always the case that codewords of not Reed-Solomon Code but only QR Code are susceptible to dirt and damage.QR Code therefore represents its error correction rate as a ratio of the total codewords. *Reed-Solomon Code is a mathematical error correction method used for music CDs etc. The technology was originally developed as a measure against communication noise for artificial satellites and planetary probes. It is capable of making a correction at the byte level, and is suitable for concentrated burst errors.