On Sat, Sep 13, 2014 at 2:46 PM, Simon Slavin <slav...@bigfraud.org> wrote:
> > > > Before Unix came along it was quite common for files to be structured, > > managed by the operating system and to be record based with file apis > > working that way. Unix turned files (and similar) into unstructured > bags of > > bytes. > > I would dispute that. Unix is not at fault here. Nor is Minix. Even the > mainframes of the day did not support transactional file systems > routinely. I can't think of any programming environment that 'expects' all > file activity to be transactional. We haven't go there yet. > > Roger is correct. Decades ago, files came in all kinds of varieties and permutations. Details varied from one OS to the next. But it was common to have a distinction between text files and binary files (with different APIs for accessing each.) It was also common to have a difference between "ordinary files" (that had to be read sequentially from beginning to end) and "random-access files", which supported operations similar to lseek(). (Once again, completely incompatible APIs existed for accessing each file type.) With binary files, one often had to specify a "block size" which was the increment in which the file was read and written. The block size was typically a property of the file and could not be changed after the file had been created. There were often restrictions on the permitted values for block sizes. And you couldn't ask the operating system to tell you whether a file was text or binary or sequential or random-access or what its block-size was; you just had to know. And bewildering problems resulted if you got it wrong. Then the boys at Bell Labs had the idea of "lets make every file be a sequence of bytes of arbitrary length". Many observers scoffed and told them that you had to have all kinds of different types of files with different APIs for "efficiency". But in the end, the Unix Filesystem was proven to be a Very Good Idea, and has become the norm ever sense. You youngsters really have concept of the chaos and nonsense we programmers had to put up with prior to the invention of the Unix Filesystem, do you? ;-) -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
