are there some special about '\x1a' symbol

Hendrik van Rooyen mail at microcorp.co.za
Wed Jan 14 03:24:17 EST 2009


"Steve Holden" <stev....enweb.com> wrote:

> Unknown wrote:
> > On 2009-01-12, John Machin <sjmachin at lexicon.net> wrote:

> > I believe that "feature" was inherited by CP/M from DEC OSes
> > (RSX-11 or RSTS-11). AFAICT, all of CP/M's file I/O API
> > (including the FCB) was lifted almost directly from DEC's
> > PDP-11 stuff, which probably copied it from PDP-8 stuff.
> > 
> > Perhaps in the early 60's somebody at DEC had a reason.  The
> > really interesting thing is that we're still suffering because
> > of it 40+ years later.
> > 
> I suspect this is probably a leftover from some paper tape data formats,
> when it was easier to detect the end of a file with a sentinel byte than
> it was to detect run-off as end of file. It could easily date back to
> the PDP-8.

We can be kind of fortunate that the ASCII chars for field separator,
record separator, file separator, unit separator did not catch on in a big
way in file formatting.  (remembering the Pick OS running on Reality...)

- Hendrik





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