History
Up to the early 1990s, many programs and data transmission channels assumed that all characters would be represented as numbers between 0 and 127 (7 bits). On computers and data links using 8-bit bytes this left the top bit of each Byte free for use as a parity, flag bit, or meta data control bit. 7-bit systems and data links are unable to handle more complex character codes which are commonplace in non-English-speaking countries with larger alphabets.
Binary files cannot be transmitted through 7-bit data channels directly. To work around this, binary-to-text encodings have been devised which use only 7-bit ASCII characters. Some of these encodings are uuencoding, Ascii85, SREC, BinHex, kermit and MIME's Base64. EBCDIC-based systems cannot handle all characters used in UUencoded data. However, the base64 encoding does not have this problem.
Perhaps the final 7-bit restriction, primarily imposed due to the pervasive use of RS-232 protocol for serial ports between devices, notably computers and modems, was lifted in the mid-1990s when RS-232 was largely replaced with Ethernet and with USB.
Read more about this topic: 8-bit Clean
Famous quotes containing the word history:
“History is not what you thought. It is what you can remember. All other history defeats itself.
In Beverly Hills ... they don’t throw their garbage away. They make it into television shows.
Idealism is the despot of thought, just as politics is the despot of will.”
—Mikhail Bakunin (1814–1876)
““And now this is the way in which the history of your former life has reached my ears!” As he said this he held out in his hand the fatal letter.”
—Anthony Trollope (1815–1882)
“Considered in its entirety, psychoanalysis won’t do. It’s an end product, moreover, like a dinosaur or a zeppelin; no better theory can ever be erected on its ruins, which will remain for ever one of the saddest and strangest of all landmarks in the history of twentieth-century thought.”
—Peter B. Medawar (1915–1987)