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:
“The principal office of history I take to be this: to prevent virtuous actions from being forgotten, and that evil words and deeds should fear an infamous reputation with posterity.”
—Tacitus (c. 55–c. 120)
“When we of the so-called better classes are scared as men were never scared in history at material ugliness and hardship; when we put off marriage until our house can be artistic, and quake at the thought of having a child without a bank-account and doomed to manual labor, it is time for thinking men to protest against so unmanly and irreligious a state of opinion.”
—William James (1842–1910)
“History is more or less bunk. It’s tradition. We don’t want tradition. We want to live in the present and the only history that is worth a tinker’s damn is the history we make today.”
—Henry Ford (1863–1947)