Felrättningskod

Felrättningskod, often translated as error-correcting code or ECC, is a system designed to detect and correct errors that occur during data transmission or storage. These errors can arise from various sources, such as noise on communication lines, defects in storage media, or hardware malfunctions. ECC works by adding redundant information to the original data, allowing the receiver to identify and fix corrupted bits.

The fundamental principle behind ECC is redundancy. Extra bits, known as parity bits or check bits, are calculated based on the original data using specific mathematical algorithms. These redundant bits are transmitted or stored along with the data. When the data is received or read, the same algorithms are applied to the received data and its redundant bits. If the calculated result matches the received redundant bits, the data is considered error-free. If there's a discrepancy, the ECC system can often pinpoint the location of the error and, in many cases, correct it by flipping the erroneous bits back to their original state.

Different types of ECC exist, each with varying levels of complexity and error-correction capability. Examples include Hamming codes, Reed-Solomon codes, and Low-Density Parity-Check (LDPC) codes. The choice of ECC depends on the specific application, the expected error rate, and the acceptable overhead in terms of data redundancy. ECC is widely used in critical applications like telecommunications, data storage devices (e.g., hard drives, SSDs), computer memory (e.g., ECC RAM), and deep-space communication to ensure data integrity and reliability.