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Groups > comp.lang.basic.misc > #250

Re: Binary formats

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Am 29.03.2012 erklärte R.Wieser:
> DonH wrote:
>>     For example, in back of book "Computer Programming
>> in Basic" (Carter and Huzan), there is an ASCII 64-character
>> set, in which binary is a 7-digit code; yet elsewhere can be
>> 8-digit, etc.
>
> I'm afraid you misunderstood that.  ASCII is the standard in which the
> characters beteen codes 32 and 126 are defined (human readable), as well as
> most of the characters below code 32 and ofcourse 127 (for special purposes,
> like Carriage-return=13 and Linefeed=10.  127 *was* used as DEL) .   AFAIK
> there is *no* 64-character ASCII standarized definition.

Not ASCII, but the originally 5-bit Baudot code:
<http://en.wikipedia.org/wiki/Baudot_code>
used for teleprinters.

BTW, the 7-bit ASCII was designed that it /could/ be used as a 6-bit
(=64 chars) code (without lowercase characters), but I've never
encountered such an use.

>
> As for ASCII in 7- or in 8-bit ?  That is a bit of cheating (pun not
> intended):  The smallest unit in which current PCs store information is a
> "byte" (or more correctly: an octet) consisting outof 8 bits.  When an ASCII
> character is stored into such a byte the highest/leftmost bit is simply
> always Zero.

But that's only true for the internal representation of the code.
If transferred to external devices like printers via a RS232 line
the eighth bit could be used as a parity bit.
You had to select the parity on both devices either off or on.
If no parity was selected, then usually the parity bit was set to "0",
but I used devices which allowed to set it to "1".
If parity was used you had to select "odd" or "even" parity and the
parity bit was then set according to match the other 7 bits.
e.g. "A" is Hex 41 = Dec 65 = Oct 101 = Bin 01000001
With parity set to "odd", the binary value 11000001 was sent to the
printer.

> If-and-when you see a character which has the highest bit set (meaning: its
> code is in the range 128 ... 255) its is *not* ASCII.
>
> Although, IBM (the company) did create a set of special characters, some of
> which not even letters but graphics (among others to draw boxes with), and
> did give it the name "extended ASCII".  That name somehow stuck.   But its
> just not standarized. 

Even IBM superseded it later on with "Code Pages", the originally
"extended ASCII" became Code Page 437.

Helmut.

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Binary formats "DonH" <donlhumphries@bigpond.com> - 2012-03-28 07:18 +1100
  Re: Binary formats "R.Wieser" <address@not.available> - 2012-03-27 23:42 +0200
    Re: Binary formats "DonH" <donlhumphries@bigpond.com> - 2012-03-29 06:15 +1100
      Re: Binary formats "R.Wieser" <address@not.available> - 2012-03-29 01:17 +0200
        Re: Binary formats Helmut_Meukel <Helmut_Meukel@bn-hof.invalid> - 2012-03-29 13:53 +0200
          Re: Binary formats "R.Wieser" <address@not.available> - 2012-03-29 14:30 +0200
            Re: Binary formats Helmut_Meukel <Helmut_Meukel@bn-hof.invalid> - 2012-03-29 21:01 +0200
              Re: Binary formats Hector Alfaro <alfaropas@ceropublicidad.com> - 2012-04-01 15:25 -0430
          Re: Binary formats "DonH" <donlhumphries@bigpond.com> - 2012-04-04 06:09 +1000
            Re: Binary formats Helmut_Meukel <Helmut_Meukel@bn-hof.invalid> - 2012-04-05 10:41 +0200
              Re: Binary formats "DonH" <donlhumphries@bigpond.com> - 2012-04-06 05:54 +1000
                Re: Binary formats ralph <nt_consulting64@yahoo.net> - 2012-04-05 21:21 -0500
        Re: Binary formats "news@rtrussell.co.uk" <news@rtrussell.co.uk> - 2012-03-29 01:32 -0700
  Re: Binary formats Helmut_Meukel <Helmut_Meukel@bn-hof.invalid> - 2012-03-27 23:34 +0200

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