In a recent note, "Shmuel Metz (Seymour J.)" said: > Date: Sun, 10 Sep 2006 00:28:32 -0300 > > In <[EMAIL PROTECTED]>, on 09/08/2006 > at 06:11 PM, Bernd Oppolzer <[EMAIL PROTECTED]> said: > > >BTW, on older machines (not IBM) there were concepts like storage > >tags, which allowed to detect the use of uninitialized variables > >even for binary values. I don't understand why these concepts never > >reached the market. > > They did: Burroughs, now part of Unisys. RCA. Probably others as well. > Didn't such tagging extend to data types, fixed vs. floating, so an attempt to perform a floating point operation on a fixed point field was detected as an error?
Requires a paradigm shift -- no clearing acquired storage with MVC[L], which would have trapped as "Attempt to perform character operation on floating (e.g.) operand." And clearing acquired storage would have circumvented the intended protection against fetching from unassigned storage. I believe such machines also had hardware array subscript calculation, but the concept of data types was rudimentary -- the paradigm was ALGOL, which had fixed, and floating, and (multiply dimensioned) arrays of those, but no support for "array of struct". I recall Bill Waite's describing his ordeal trying to port to such systems a large FORTRAN program that depended on large arrays of amorphous storage. And I of know one regular contributor to this list who has strongly opposed the "nanny language" concepts of enforcing type conformity and array bounds on programmers. -- 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
