RE: access path

midrange-l-request@xxxxxxxxxxxx wrote:

>   4. access path (Leif Svalgaard)
>
>I have been working on and with this machine for upwards
>of two sunspot cycles, and I have a confession to make:
>I see references on this list and elsewhere to an "access
>path" to a file. I have studied the internals of this machine,
>I have looked far and wide, but I'm still baffled: what the
>h*** is an "access path"? where is it? what does it do?
>Why must it be "rebuilt" at times and what does that entail?
>Somebody enlighten me...

"...enlighten..."? Well, we'll see.

>From the venerable _IBM System/38 Technical Developments_ chapter 'System/38 
>data base concepts':

"All online data in System/38 is stored as records in data base files. A data 
base file has three primary attributes: the _format_ of records within that 
file, the _access path_ for the records within that file, and the _members_ of 
that file." And "The access path for a file defines the ordering of records 
within that file and provides for either random or sequential accessing of 
those records."

The interesting part is the reference to "attributes". Perhaps not an 'object' 
at all as such, but simply located at some offset in some space of the file 
object?

More detail is in the book, but none seems clear enough to help.

Tom Liotta

-- 
-- 
Tom Liotta
The PowerTech Group, Inc.
19426 68th Avenue South
Kent, WA 98032
Phone  253-872-7788 x313
Fax    253-872-7904
http://www.powertechgroup.com


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