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Six-bit character code
Peter Flass (
talk)
13:54, 7 June 2012 (UTC)
BCD (6-bit)
Peter Flass (
talk)
13:55, 7 June 2012 (UTC)
(to be continued)-- Mcapdevila ( talk) 16:57, 18 June 2012 (UTC)
Per Wikipedia:Merging, proposed merge discussions should take place on a single page. As I was confused by the separate discussion at talk:Six-bit character code, I took the liberty to merge it. Thanks, Wbm1058 ( talk) 17:36, 19 October 2012 (UTC)
I guess there's no reason to merge and some reason not to, so I removed the merge proposal. I see the distinction between various BCD codes and other codes. Confusingly most 6-bit codes are called BCD even where this is incorrect. I did decide to "be bold" and made changes to this article, the most significant being discussion of the development of BCD based on information from Punched card and Binary-coded decimal. Peter Flass ( talk) 14:06, 31 December 2013 (UTC)
To distinguish BCD from other six-bit codes I added the following: "BCD encodes the characters '0' through '9' as the corresponding binary values". Peter Flass ( talk) 23:50, 31 December 2013 (UTC)
Does it really contain two commas and no period? Well, I've seen stranger things, but if so, the table should annotate this explicitly as a bizarre anomaly. — MaxEnt 10:36, 25 June 2014 (UTC)
Good catch, thanks. Peter Flass ( talk) 11:03, 25 June 2014 (UTC)
No, but the 704 code does contain two minus signs. From the IBM 704 Fortran manual: "Note 1: There are two - signs. Only the 11 punch minus may be used in source program cards. Either minus may be used in input data to the object program; object program output has the 8-4 minus." In the BCDIC days, there were two different maps of characters to punches, one used for business, the other for science. I just changed the 704 table to match Fortran commonly used on the 704. I wonder if there should be tables indicating the punched card codes in addition to the in-memory codes. Gah4 ( talk) 19:44, 6 May 2015 (UTC)
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At 0x0032 is the record mark, which was not proposed separately due to its similarity to the double dagger. At 0x0077 is the group mark, which is not in Unicode yet.
Note that 0x0032 is a 16 bit hexadecimal value meant to represent a six bit octal value, but it doesn't.
Also, should the row headers be of the form 0x0 where x is the appropriate octal digit? Otherwise, there is no reason for the row and column headers to be three digit octal characters. Gah4 ( talk) 08:33, 22 February 2017 (UTC)
@ Gah4: I just undid your undo with additional citations and explanations (I was actually in the middle of it when I hit your undo as an edit conflict). I think I have it straight now. Is that any clearer? 71.41.210.146 ( talk) 05:24, 23 April 2017 (UTC)
@ Gah4: I checked your recent edit adding the 716 printer info, and I'm not sure it's right. The table in the source (and, indeed, the entire printer) seems to go from virtual punched cards to print; there is no 6-bit binary representation at all.
And indeed as explained on p. 52, it's up to software to provide this. The printer is fed with transposed cards, 72 columns (2 36-bit words) at a time. Repeat for 12 virtual card rows per line printed.
I still don't fully understand it; there's no obvious way to print a blank space! An unpunched column corresponds to "*". (Is that actually a symbol or some sort of footnote/special handling notation?) It's a pretty baroque system by modern standards, so I probably just don't understand it, but are you sure you do? 71.41.210.146 ( talk) 08:49, 23 April 2017 (UTC)
Don't confuse printer codes (or keypunch codes) with character sets. You can run FORTRAN, or any other compilers, on machines with printers that don't have some of the characters. I remember running FORTRAN on machines wher the printed/punched characters didn't match the values the compiler used. Peter Flass ( talk) 19:19, 24 April 2017 (UTC)
<html>
, <head>
, <body>
, etc. would cause problems.
References
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As I understand it, there is a metal plate in the 026 and 029 keypunches that contains the dot patterns. There are x and y positions, that are not powers of two, though I don't remember the numbers. There is even one character on the 029 that doesn't have a dot pattern, 0-8-2, but does have a key. There was no room to add it. For wheel or train printers, there isn't much reason for a power of two, as long as the printer keeps track of which character is where. Gah4 ( talk) 19:35, 26 July 2020 (UTC)
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Six-bit character code
Peter Flass (
talk)
13:54, 7 June 2012 (UTC)
BCD (6-bit)
Peter Flass (
talk)
13:55, 7 June 2012 (UTC)
(to be continued)-- Mcapdevila ( talk) 16:57, 18 June 2012 (UTC)
Per Wikipedia:Merging, proposed merge discussions should take place on a single page. As I was confused by the separate discussion at talk:Six-bit character code, I took the liberty to merge it. Thanks, Wbm1058 ( talk) 17:36, 19 October 2012 (UTC)
I guess there's no reason to merge and some reason not to, so I removed the merge proposal. I see the distinction between various BCD codes and other codes. Confusingly most 6-bit codes are called BCD even where this is incorrect. I did decide to "be bold" and made changes to this article, the most significant being discussion of the development of BCD based on information from Punched card and Binary-coded decimal. Peter Flass ( talk) 14:06, 31 December 2013 (UTC)
To distinguish BCD from other six-bit codes I added the following: "BCD encodes the characters '0' through '9' as the corresponding binary values". Peter Flass ( talk) 23:50, 31 December 2013 (UTC)
Does it really contain two commas and no period? Well, I've seen stranger things, but if so, the table should annotate this explicitly as a bizarre anomaly. — MaxEnt 10:36, 25 June 2014 (UTC)
Good catch, thanks. Peter Flass ( talk) 11:03, 25 June 2014 (UTC)
No, but the 704 code does contain two minus signs. From the IBM 704 Fortran manual: "Note 1: There are two - signs. Only the 11 punch minus may be used in source program cards. Either minus may be used in input data to the object program; object program output has the 8-4 minus." In the BCDIC days, there were two different maps of characters to punches, one used for business, the other for science. I just changed the 704 table to match Fortran commonly used on the 704. I wonder if there should be tables indicating the punched card codes in addition to the in-memory codes. Gah4 ( talk) 19:44, 6 May 2015 (UTC)
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I have just modified one external link on BCD (character encoding). Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
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Cheers.— InternetArchiveBot ( Report bug) 08:43, 23 October 2016 (UTC)
At 0x0032 is the record mark, which was not proposed separately due to its similarity to the double dagger. At 0x0077 is the group mark, which is not in Unicode yet.
Note that 0x0032 is a 16 bit hexadecimal value meant to represent a six bit octal value, but it doesn't.
Also, should the row headers be of the form 0x0 where x is the appropriate octal digit? Otherwise, there is no reason for the row and column headers to be three digit octal characters. Gah4 ( talk) 08:33, 22 February 2017 (UTC)
@ Gah4: I just undid your undo with additional citations and explanations (I was actually in the middle of it when I hit your undo as an edit conflict). I think I have it straight now. Is that any clearer? 71.41.210.146 ( talk) 05:24, 23 April 2017 (UTC)
@ Gah4: I checked your recent edit adding the 716 printer info, and I'm not sure it's right. The table in the source (and, indeed, the entire printer) seems to go from virtual punched cards to print; there is no 6-bit binary representation at all.
And indeed as explained on p. 52, it's up to software to provide this. The printer is fed with transposed cards, 72 columns (2 36-bit words) at a time. Repeat for 12 virtual card rows per line printed.
I still don't fully understand it; there's no obvious way to print a blank space! An unpunched column corresponds to "*". (Is that actually a symbol or some sort of footnote/special handling notation?) It's a pretty baroque system by modern standards, so I probably just don't understand it, but are you sure you do? 71.41.210.146 ( talk) 08:49, 23 April 2017 (UTC)
Don't confuse printer codes (or keypunch codes) with character sets. You can run FORTRAN, or any other compilers, on machines with printers that don't have some of the characters. I remember running FORTRAN on machines wher the printed/punched characters didn't match the values the compiler used. Peter Flass ( talk) 19:19, 24 April 2017 (UTC)
<html>
, <head>
, <body>
, etc. would cause problems.
References
Hello fellow Wikipedians,
I have just modified 2 external links on BCD (character encoding). Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
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(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 03:54, 13 July 2017 (UTC)
As I understand it, there is a metal plate in the 026 and 029 keypunches that contains the dot patterns. There are x and y positions, that are not powers of two, though I don't remember the numbers. There is even one character on the 029 that doesn't have a dot pattern, 0-8-2, but does have a key. There was no room to add it. For wheel or train printers, there isn't much reason for a power of two, as long as the printer keeps track of which character is where. Gah4 ( talk) 19:35, 26 July 2020 (UTC)