Unknown wrote: > On 2009-01-12, John Machin <sjmac...@lexicon.net> wrote: > >> I didn't think your question was stupid. Stupid was (a) CP/M recording >> file size as number of 128-byte sectors, forcing the use of an in-band >> EOF marker for text files (b) MS continuing to regard Ctrl-Z as an EOF >> decades after people stopped writing Ctrl-Z at the end of text files. > > 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.
regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ -- http://mail.python.org/mailman/listinfo/python-list