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0 pointswongarsu6y ago0 comments

Wikipedia supports this:

> Character 26 was used to mark "End of file" even if the ASCII calls it Substitute, and has other characters for this. Number 28 which is called "File Separator" has also been used for similar purposes. [1]

I think today we would think of character 4 (End of Transmission, Ctrl-D) as the end of file/input marker, but historically Character 26/Ctrl-Z was used, even on disk.

1: https://en.wikipedia.org/wiki/Substitute_character

0 comments

pwdisswordfish26y ago

See, this is why you should not believe Wikipedia.

The DOS syscall interface has no concept of an EOF character. ^Z being considered EOF was a feature of the COPY command, later replicated by the runtimes of various languages targetting DOS.

http://jdebp.info/FGA/dos-character-26-is-not-special.html

Doctor_Fegg6y ago

Not just DOS. CP/M also used CTRL-Z, principally because file lengths weren’t stored on disk - just the list of 128-byte blocks. So to get granularity beyond multiples of 128, you need an explicit EOF character.

giovannibajo16y ago

I think TYPE would also treat ^Z as a terminator of the file. I think it was common in DOS to have binary files with a textual header followed by ^Z, that would hide the binary part.

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