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From: andy@garfield (Andy Lowry)
Newsgroups: comp.databases
Subject: Re: Data Base Machines
Message-ID: <5881@columbia.edu>
Date: 14 Sep 88 22:40:44 GMT
References: <21755@tut.cis.ohio-state.edu>
Sender: news@columbia.edu
Reply-To: andy@garfield.UUCP (Andy Lowry)
Organization: Columbia University CS Department
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In article <21755@tut.cis.ohio-state.edu> mcclure@tut.cis.ohio-state.edu (James Edward McClure) writes:
>
>	Could someone please tell me exactly what a data base machine is and
>how if differs from a DBMS (besides being hardware based)?
>
>Thanks for your help!!

A database machine is not necessarily hardware based (in the sense of
containing hardware that was specially designed for database
processing).  The term has been used in many different ways, but
generally I think they all share the feature that there is some piece
of hardware that is dedicated to some or all of the task of database
processing.  That could be anything from a general purpose computer
that isn't used for anything but database processing (in which case
there is probably a severely stripped-down low-overhead operating
system supporting the database software) to a highly engineered
collection of special-purpose hardware like associative memories and
hardware sorters.  The system configuration could be such that the
database machine sits as a self-contained unit serving as a back-end
processor providing complete database services to one or more hosts,
or it could simply mean that there are some smart peripherals like
disks with on-the-fly filters on their heads to make the disk behave
associatively.  There have been over a hundred of proposals since the
late 1960's for database machines of varying scope and complexity, and
many of these machines have been prototyped.  A few have even been
offered commercially.  A book by Stanley Su, just published this year,
gives the most comprehensive survey of the area that I have
encountered.  Here's the reference, a la Scribe:

@book(su88a,
	key="Su",
	author="Stanley Y.W. Su",
	title="Database Computers: Principles, Architectures, and
Techniques",
	publisher="McGraw-Hill",
	address="New York",
	year="1988")

If you'd like something a little less ambitious, I wrote a 30-page
survey this past spring titled "Synchronization, Communication and I/O
Factors in Database Machine Performance" that I would be glad to send
you (or anybody else).  It does not describe the machines it covers in
great detail, but rather explores the problems mentioned in the title
and the ways various designs have attempted to overcome them.  The
bibliography will also point you to many detailed papers and some
other good surveys.

-Andy Lowry