[AccessD] Defense of Access

Fascinating. 


John W. Colby
www.ColbyConsulting.com 


-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of MartyConnelly
Sent: Saturday, April 01, 2006 4:16 PM
To: Access Developers discussion and problem solving
Subject: [AccessD] Defense of Access

Someone asked me for a counter argument regarding the use of Jet and by
default Access.
So here is something I pieced together from some blogs, I can't remember
seeing anything posted here on Jet version's Red and Blue.
 
Most of these database types have good arguments against using JET but don't
realize that Active Directory Services and Exchange are built on top of JET.
Don't tell me, they would throw out these applications because of their
prejudices. Yes, Mr CIO, I know, but we have to get rid of all those Active
Directory Services that you just spent two years installing because Gasp!
it's based on a JET database engine.  I really like bringing this up to the
one trick pony Oracle types who work on Windows. It is fun to watch them
squirm for awhile; although a knowledgeable db type can counter this.

 So here is some info to throw at them.

JET was originally part of Access (or FoxPro for some of the very early MS
versions). It split into Jet Red and Jet Blue. Jet Blue was used for
MSExchange and Active Directory and is shipped with Windows 2000 and later.
It's now known as ESE. Jet Red was still shipped with Access. All throughout
it's history, Jet Red has been freely distributable. Many many many VB apps
were shipped with Jet Red.

JET Red was an ISAM originally developed by Microsoft for BC7, compiled
basic. JET Blue was originally developed by Microsoft as a prospective
upgrade for Access, but it was never used in this role. JET Red and JET Blue
began sharing the common JET moniker in the Spring of 1990 when a query
technology, QJET, was developed that would host on both Red and Blue.

JET Blue went on to be used by Microsoft Exchange, Active Directory and many
many other Windows services. JET Blue was a private API for many years, but
became a published API in April of 2005 when three middle ware applications
not covered by the Windows EULA chose it as their data store.
Now anyone can use JET Blue.

Extensible Storage Engine (ESE) -- the Active Directory database engine.
ESE (Esent.dll) is an improved version of the Jet database that is used in
Microsoft Exchange Server versions 4.x and 5.5. It implements a transacted
database system, which means that it uses log files to ensure that committed
transactions are safe.
The ESE engine used by Active Directory is based on Microsoft's Jet database
technology. Jet uses a b-tree file structure with transaction logs to ensure
recoverability in the event of a system or drive failure.

JET Red is a file sharing technology with page level locking and best effort
crash recovery. JET Blue on the other hand is designed to be embedded in a
server application, does not share files, has write ahead logging for
guaranteed crash recovery and has record level locking. JET Blue does not
ship with a query engine but instead relies on applications to write their
own queries as C++ ISAM code.

With the release of Access 12 the Jet Red development team has been split
off from it's old SQL Server department and is free to develop on it's own.


Extensible Storage Engine API's
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ese/ese/ext
ensible_storage_engine_errors.asp

Access 12's new data engine ACEDB
http://blogs.msdn.com/access/archive/2005/10/13/480870.aspx


--
Marty Connelly
Victoria, B.C.
Canada



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