#Base64 encoding wikipedia software#
In other words, the software was not 8-bit clean. Used to denote the end of a line of text.Įven though eight bits was being transmitted over the wire, the 8th bit would often get discarded or mangled, since there was no requirement to preserve it in fact, some protocols required the 8th bit to be set to zero, such as the initial SMTP RFC as quoted below. In accordance with this standard, the sequence should be The receiverĬonverts the data from the standard form to its own internal form. Representation (see the TELNET specification). The sender converts the data from its internalĬharacter representation to the standard 8-bit NVT-ASCII Regardless of whether the sending and receiving hosts areĭissimilar. Standard NVT-ASCII representation when transmitting text, This means that characters must be converted into the
Stores NVT-ASCII as four 9-bit characters in a 36-bit word.įor the sake of simplicity, all data must be represented in MTP as NVT-ASCII as four 8-bit EBCDIC codes in a 32-bit word. PDP-10's generally store NVT-ASCII as five 7-bit ASCIIĬharacters, left-justified in a 36-bit word. NVT-ASCII has different data storage representations in different Representations in the two systems are different. Perform certain transformations on the mail because data storage Mail is transferred from a storage device in the sending host to a For example, RFC 772 says: MAIL REPRESENTATION AND STORAGE Therefore, mail transfer functions were initially defined for transferring relatively short messages in plain text specifically, "NVT-ASCII". Those machines often had differing character encodings – ASCII vs EBCDIC – or even different byte sizes, 8-bit bytes vs 6-bit vs. There were also several attempts at creating file transfer protocols that would work in different machines (mail was initially a function of the FTP protocol, primarily as the MAIL and MLFL commands, then split into MTP, later SMTP.). The earliest iterations of NCP as used by ARPAnet were more like bit streams than byte streams, or attempts to negotiate a convenient byte size the 8-bit byte was only standardized on much later. There is a good Wikipedia article on this.
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