Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.basic.misc > #262

Re: Binary formats

Show all headers | View raw

"Helmut_Meukel" <Helmut_Meukel@bn-hof.invalid> wrote in message 
news:jl1igf$f7n$1@dont-email.me...
> 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.
>
>

# I assume that a "parity bit" is a "check sum" at binary level.
   However, there seems no such digit in the 7-bit code of the "64 character 
set", as the first 32 binary codes start with 0, while the second start with 
1, giving a code range of 0100000 (space), to 1011111 (leftwards arrow). 

Back to comp.lang.basic.misc | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

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

csiph-web