In a recent note, Joe Zitzelberger said: > Date: Tue, 7 Jun 2005 08:38:25 -0400 > > The big difference that I see is that z/OS keeps design decisions > around long after the need for them is gone. For example, Unix dropped > 'card' type metaphors as soon as readers and punches departed -- z/OS > still has them in every nook and cranny a quarter of a century later. > There are many other examples, but I've held forth on those at length > previously, there is no need to do so again. > Credit for the difference may be due more to historical accident than to cultural differences. In my dim memory the ancestral open systems arose with perforated tape rather than cards as the modal input and storage medium. (Paper tape readers are mechanically simpler, thus cheaper, than card readers.) So the design was not oriented to unit records.
IBM, in contrast, tried to coerce perforated tape into the unit record mold. I recall that there were legendary difficulties reading on a 1620 tapes that lacked the necessary record separator codes. I think the symptom was overflowing buffer and wrapping memory. I don't know if it stopped when the READ instruction was finally overlaid. I don't recall whether the deficiency was in the control unit or the FORTRAN runtime system. -- gil -- StorageTek INFORMATION made POWERFUL ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
