Messages in this thread | | | Subject | Re: Bash Issues | Date | Mon, 13 Dec 1999 23:56:00 -0300 | From | Horst von Brand <> |
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"Jeff V. Merkey" <jmerkey@timpanogas.com> said: > Alan Cox wrote: > > ASCII is 7bit. I think you mean the PC character set non standard... > > I think ALTCHARSET gets you the PC characters (cp437 is it ?) > ^^^^^^^^^^^^^^^^^^^^^^^^^^
> I think this is where the communication breakdown occurred, our use of > the "ASCII" term. In PC lingo (and in all PC based literature since > about 1986 on the subject), ASCII is assumed to be the PC character set > for those of us from the "DOS/Windows world". To unix folks, "ASCII" > means something different -- a richer and more specific definition as to > what this refers to (which is why I and some unix folks seem to talk > past each other on this topic).
ASCII has meant, from the prehistory of computing on, the American Standard Code for Information Interchange. It is a 7 bit code, represented in octets with the leading bit a partity bit for error detection. As a true, died-in-the-wool standard, most computer, terminal, printer, modem, ... manufacturers adopted it. As an operating system that runs on a wild veriety of hardware, and talks to an even more bewildering variety of peripherals, Unix (and thus Linux) by and large uses true ASCII (but adds a few quirks of its own, like using '\n' and not "\r\n" to end a line). Then came along the PC, which had no use for the parity bit, and Bingo! Yet another non-standard is born by using it to get space for a new bunch of characters. The copious PC-centered literature (which you mention, and which is mostly clueless anyway) deluded a whole generation that this was ASCII. The same literature also assumed every screen could handle its non-ASCII characters, which is _very_ far from the truth. There are even terminals that can't even handle the full ASCII set! Thankfully now on the brink of extinction.
ascii(7) elaborates. -- Horst von Brand vonbrand@sleipnir.valparaiso.cl Casilla 9G, Viña del Mar, Chile +56 32 672616
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