john@genrad.UUCP (John P. Nelson) (08/05/85)
In article <3403@decwrl.UUCP> jcampbell@mrfort.DEC (Jon Campbell) writes: >What many users have suggested is that I put a "file header" at the >beginning of each file. This seems like a reasonable approach, except >that existing FORTRANs do not put such cruft at the beginning of files >now. So? Existing FORTRANS do not use an invisible header either! No matter how you implement this, you lose backward compatibility! This is a non-argument. >I'm not particularly interested in the way it might be done, >except that it cannot be part of the actual data and it cannot be a separate >file. Why not? As long as it is invisible to the FORTRAN task, what difference does it make? Presumably, other tasks will not be able to parse this file properly without knowing about the "magic" information, no matter HOW it is implemented. >There are many such operating systems (which have file information in >invisible or hidden headers) around, such as the ATEX text-processing >system used in many newspapers. Ordinary programs and utilities need >not ever look at the invisible header if they are interested in the >data only. How can they parse this data properly if they don't read the header? EXCUSE ME, but you were talking about fixed-length records, and records with length introducers (instead of using the normal text record terminator, newline). You have yet to give an example where ordinary general-purpose UNIX tools could be used, but that "magic" header information was required! >I think that you folks who are having a look at creating UNIX utilities >which can do serious data manipulation, read magtapes from "foreign" >operating systems and munge it (without having to read the ANSI >magtape header files by hand), or write utilities which can look at >different files without knowing a priori the file format, will >recognize the problem that I am trying to address. I see quite clearly. I still don't see the point. If its FOREIGN, then translation is required, anyway. The second argument is silly, since all of the unix utilities that do not manipulate the DATA within a file (cp, mv, tar, etc.) work just fine now with header information within the file, but would be broken (i.e. would have to be rewritten) to handle the files with "headers", while any of the programs that manipulate the DATA within a file MUST know what is in the header to be able to parse the data properly, and indeed, even to be able to write a resulting output file with the same attributes. Excuse me, but it seems to me that you have the whole argument backwards!!!! John P. Nelson (decvax!genrad!john)