Decimal computer Decimal computer Decimal computers are computers which can represent numbers and addresses in decimal as well as providing instructions to operate on those numbers and addresses directly in decimal, without conversion to a pure binary representation. Some also had a variable wordlength, which enabled operations on numbers with a large number of digits. Early computers that were exclusively decimal include the ENIAC, IBM NORC, IBM 650, IBM 1620, IBM 7070. In these machines, the basic unit of data was the decimal digit, encoded in one of several schemes, including binary-coded decimal or BCD, bi-quinary, excess-3, and two-out-of-five code. Except for
Repeating decimal (base 12) is 12 (base 10), 10^2 (base 12) is 144 (base 10), 21 (base 12) is 25 (base 10), ᘔ5 (base 12) is 125 (base 10), ... Repeating decimals (also called decimal sequences) have found cryptographic and error-correction coding applications. In these applications repeating decimals to base 2 are generally used which gives rise to binary sequences. The maximum length binary sequence for 1/"p" (when 2 is a primitive root of "p") is given by: These sequences of period "p" − 1 have an autocorrelation function that has a negative peak of −1 for shift of ("p" − 1)/2.