[155] in sapr3-soft
Re: SAP question.
daemon@ATHENA.MIT.EDU (DJ Adams)
Fri Apr 18 09:37:24 1997
To: sapr3-soft@MIT.EDU
Date: 18 Apr 1997 08:36:59 -0400
From: "DJ Adams" <dj@reitz-adams.org> (by way of SAP Moderator <sap-request@realtimeusa.com>)
Greetings
One way of looking at the 3-tier architecture of R/3 (presentation -
application - database) is just to consider that it's really two tier, and
the 'fat' tier is actually split between application processing (the
business logic) and db services.
The 'thin' tier is the presentation level and "simply" squirts info to the
screen and takes input from the keyboard/mouse (sorry SAPGUI team, I mean
well). The good design of this and the comms protocol between this thin
tier and it's comms partner the middle application tier means that data
flow is low-vol (measured in bytes) and therefore WAN is possible here.
*Don't* think of SQLNet here - there's no SQL flying between the thin and
fat ends.
The split of the 'fat' end means that you can (to a certain level) throw
hardware at performance issues and do load balancing. Comms between the two
halfs of the fat end should be fast e.g. FDDI, fast ethernet, (ultimately
loopback of course - stick them on the same host ;-)).
So one adv of 3-tier is flexibility for the performance issues.
Just my 2p worth, of course
DJ
---
Belakimem wrote in article <5j0m1h$hee@nexus.netconcepts.com>...
>I read all the computer press but am still confused.
>What is the real adavantage of 3 tier architecture?
>I'm thinking of learning a new application development product ( I
>currently know Informix 4GL ) and originally thought of Visual Basic.
>Yet, I have heard that this traditional 2 tier method is basically flawed
>as the client is too "fat" ( all the code resides on client ) and the
>newtwork gets overloaded over a ceratian number of users. In other
words, it cannot be really used for a large enterprise application. Also,
it is better to have business logic in a middle layer which could bve accessed
>by many different clients products.
So what is best, SAP R3?, what advantage does this have over VB? Will VB
>go 3-tier?
>Any thoughts or commments would be greatly appreciated.
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