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
Dot-decimal notation table in RFC 790 ("Assigned Numbers") used the dotted decimal format, zero-padding each number to three digits. RFC 1123 ("Requirements for Internet Hosts – Application and Support") from October 1989 mentions a requirement on host software to accept “IP address in dotted-decimal ("#.#.#.#") form”, although it notes “[t]his last requirement is not intended to specify the complete syntactic form for entering a dotted-decimal host number”. A separate IETF draft to define textual representation of IP addresses expired. A popular implementation of IP networking, originating in 4.2BSD, contains a function "inet_aton()" for converting IP addresses in character string representation to internal