On 2009-01-14, Steve Holden <st...@holdenweb.com> wrote: > 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.
You're probably right. That's why the "delete" character is all 1's (all holes). It's easy to punch more holes -- un-punching them is pretty arduous. -- Grant -- http://mail.python.org/mailman/listinfo/python-list
