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Questions tagged [ascii]

For questions about the 7-bit ASCII character set, including its control codes. Not for binary-coded-decimal (even if some Intel instructions call it "adjust for ASCII").

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24
votes
2answers
2k views

What was the ASCII end of medium (EM) character intended to be used for?

I can find information about how characters were used to structure transmissions in general, and I can find information about transmission characters which are still commonly used today, though ...
30
votes
2answers
3k views

Why wasn't EBCDIC designed with contiguous alphanumeric characters?

Inspired by this question on ASCII, I have wondered similar things about EBCDIC. At work we have an EBCDIC file that gets sent to a mainframe (I presume an IBM one) and to view it on my laptop I ...
67
votes
5answers
12k views

Why wasn't ASCII designed with a contiguous alphanumeric character order?

Anyone who has dealt with strings at a low level (e.g., writing a parser in C), knows that doing so tends to involve frequent checks of—either manually, or through isalpha(), isalnum(), etc—whether a ...
5
votes
4answers
427 views

What characters which were in use at the time were excluded from ASCII?

The American Standard Code for Information Interchange is a 7-bit character encoding. Work on the standard began in 1960 and the first edition was published in 1963. The standard attempted to ...
33
votes
2answers
3k views

Why are the symbols on the number keys of PC & Mac keyboards different to ASCII keyboards?

On a US-layout PC keyboard, the symbols above the number keys are as follows: Whereas the keyboard on an Apple II is different: Note, for example, the '(' and ')' symbols are now above 8 and 9, and '...
26
votes
4answers
7k views

History of Ctrl-S and Ctrl-Q for flow control

Which OS was the first to use Ctrl-S and Ctrl-Q on the console for pause and continue? I first discovered Ctrl-S in IBM PC DOS 1.1.
10
votes
1answer
458 views

What's the deal with System/360's “USASCII” mode?

The original System/360 architecture had a bit in the Program Status Word that would select an "USASCII" mode rather than the usual EBCDIC. Setting this bit changed how the BCD arithmetic operations ...
33
votes
5answers
4k views

Executable ASCII files before x86?

I've known about a technique allowing to bootstrap arbitrary 16-bit x86 code from a subset of instructions representable as printable ASCII bytes since the early 1990s. The first example of an ASCII ...
4
votes
2answers
312 views

What file systems / encapsulation formats used ASCII?

Most of the ASCII character codes make sense in the context of data transmission, e.g. ␄, ␗, ␖ (end of transmission, end of transmission block, synchronisation). However, there are also codes such as ␜...