Re: Need help to understand difference, and contrast between Relational database model and the Object-Oriented model

"Anthony W. Youngman" <thewolery_at_nospam.demon.co.uk> wrote in message news:tdAoO4Gsef+$EwA8_at_thewolery.demon.co.uk... [snip]
> Except that in this particular case, what you are thinking of as a
file
> is actually the entire disk as a raw device ...
>
> Not having any experience of R83 I can't be sure, but I think you'll
> find "the database is the computer" :-)
[snip]

In a sense that it true in that typically the file pointers reside in a dictionary, the dictionaries reside in a VOC or master dictionary (the account), and the accounts pointers reside in the system account. Basically. I believe that is still the strategy of many platforms, but they also support other file implementations as well. Of course I have to
wonder if disk fragmentation would not disrupt this as much as frame overflow. I don't think this is an issue.

However, to my knowledge R83 is a standard for the language and functionality rather than a definition of how the files are physically implemented within the system. For instance, our ARev code is R83 compliant, so we don't make use of any of the form / screen generation features present in ARev. The point to R83 was to extend the platform independence of the "OS" to the code level.

An example of an R83 issue would be the ability to transfer control from one program to another in BASIC. A permanent transfer existed for a long time (as in "CHAIN".) Different platforms developed various language syntax to temporarily transfer control to another program and then return control to the original program. This took the form of a PERFORM or EXECUTE statements with various different parameters and features that were in need of some standardisation. This is of course distinct from using a SUBROUTINE CALL (I guess comparable to using an interface), or a GOSUB (a local function) or shelling out to the host operating system.

Perhaps wiser soles could expand upon or correct some of this.

Regards, Dave Horsman Received on Tue Aug 10 2004 - 07:55:26 CEST