Re: The IDS, the EDS and the DBMS

"Laconic2" <laconic2_at_comcast.net> wrote in message news:RaSdnZVtR528Z9zcRVn-sg_at_comcast.com...
>
> "Marshall Spight" <mspight_at_dnai.com> wrote in message
> news:rgm0d.168571$mD.134957_at_attbi_s02...
> > or in local parlance, there is logical structure and
> > physical structure.
>
> That parlance is even more local than you might think.
>
> After you get done talking to the Oracle guru, and he finishes explaining
> to you that a "database block is phyisical", try going across the hall to
> the operating system guru. Here's what he says:
>
> "If by 'database block' he means 'file block', then he's wrong. File
> blocks are virtual. They are mapped into logical blocks by the file mapping
> feature of the OS. Logical blocks are the same size as file blocks, but
> they have only a one dimensional address, at least on a single spindle.
>
> Even logical blocks are not physical. Logical blocks are further
> translated into one or more disk sectors. Now that's physical!"
>
> Now go down the hall to the guy who designs disk controllers. He says:
>
> "I know the OS guy told you that 'sectors' are physical, but that's only
> an illusion!
>
> Lemme tell you what's REALLY going on...."

It's turtles all the way down.

My implementation is built on top of some other guy's interface.

Marshall Received on Sat Sep 11 2004 - 03:17:32 CEST