Analysis of information sources in references of the Wikipedia article "RAID" in English language version.
A typical IBM 7030 Data Processing System might have been comprised of the following units: [...] IBM 353 Disk Storage Unit – similar to IBM 1301 Disk File, but much faster. 2,097,152 (2^21) 72-bit words (64 data bits and 8 ECC bits), 125,000 words per second
Patterson recalled the beginnings of his RAID project in 1987. [...] 1988: David A. Patterson leads a team that defines RAID standards for improved performance, reliability and scalability.
Since a large number of bits are handled in parallel, it is practical to use error checking and correction (ECC) bits, and each 39 bit byte is composed of 32 data bits and seven ECC bits. The ECC bits accompany all data transferred to or from the high-speed disks, and, on reading, are used to correct a single bit error in a byte and detect double and most multiple errors in a byte.
We were not the first to think of the idea of replacing what Patterson described as a slow large expensive disk (SLED) with an array of inexpensive disks. For example, the concept of disk mirroring, pioneered by Tandem, was well known, and some storage products had already been constructed around arrays of small disks.
