"Service Oriented" Architectures, Part 1 - Gartner Blog Network
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
SPA-00-7425SPA-401-068SPA-401-070SPA-401-167SPA-ARCH-259SPA-200-126 "Service Oriented" Architectures, Part 1 Published: 12 April 1996 Analyst(s): W. Roy Schulte, Yefim V. Natis A service-oriented architecture is a style of multitier computing that helps organizations share logic and data among multiple applications and usage modes. Analysis The proliferation of computing styles, such as C/S, Internet, batch, mobile and interenterprise EDI, has increased the need to share data and logic among multiple application systems. However, conventional application topologies make it difficult to share data and almost impossible to share logic. In response, developers are increasingly considering a "service oriented" architecture, a way of structuring programs using multitier design techniques and middleware (see Figure 1).
Figure 1. Service-Oriented Architecture
Enterprise servers/hosts Enterprise
databases
Services: Tier
Shared business A
logic and data I/O
Updates Results
Queries Error feedback
Mobile Mobile Local batch EDI Internet
Online Tier
agent(s) application application application server B
application
application
Trans- Trans-
Transfer EDI
action action
queues file
files files
WAN
Transfer
queues LAN or WAN
WAN LAN or
WAN WAN Tier
Application Agent(s) C
Batch 3-tier C/S Browser
application presentation
Local
Data Inter- Desktop Internet Dumb
Disconnected mobile client enterprise PC client terminal
Source: Gartner Group
A service-oriented architecture leverages the principle that many aspects of processing logic are
inherently tied to the data rather than associated with a particular application or mode of processing
(see Note 1). For example, the business rules, integrity checks and sequence of steps to enter an
order or update a bank account may be common to all users (online or batch) of that data. The code
associated with a specific function is organized in Tier A as a modular "service" or software "server"
program that can be invoked by one or more "requesters," or software "client" programs. A service
treats all transactions the same regardless of which client application invokes the service, although
Page 2 of 5 Gartner, Inc. | SPA-00-7425SPA-401-068SPA-401-070SPA-401-167SPA-ARCH-259SPA-200-126online requesters may be given priority over batch requesters in the order in which the work is
executed.
The difference between batch and online users is only on the requesting side (i.e., in tiers B and C).
All online tasks (right side of Figure 1), including C/S, Internet and dumb-terminal OLTP, must be
executed immediately because a person is waiting. This differs fundamentally from batch tasks (left
side of Figure 1), where the processing is deferred and no immediate feedback is expected. Online
tasks can be conversational, returning up-to-the-minute information about inventory levels or
account balances to a user who is deciding in real time how to proceed. Online applications can
also return input errors and other feedback from integrity checks so that the user can re-enter the
input immediately. By contrast, all forms of batch processing must save feedback from failed
transactions in files or queues for later delivery to a program or user that can correct and re-enter
the transaction. Tiers B and C hold the presentation, business rules and flow-control unique to each
application and access mode.
Service-oriented configurations are appropriate for many functions that are common between
multiple applications. However, they rarely span the wide range of application types shown in Figure
1. Moreover, they will never be a universal solution, fully replacing traditional batch and other C/S
topologies. For additional explanation, see FSIR Research Note SPA-401-071, Jan. 20, 1997.
Bottom Line: A service-oriented architecture is a style of application partitioning and targeting
(placement). It assumes multiple software tiers and usually has thin clients and fat servers (i.e., little
or no business logic on the client), but it is more than that. It organizes software functions into
modules in a way that maximizes sharing application code and data.
Core Topic
Software Infrastructure: Data
and Process Topology
Key Issue
How should data and process be centralized or distributed around
the enterprise?
Strategic Planning Assumption
Service-oriented topologies will account for more than one-third of new, mission-critical operational
applications by 2001, up from less than 10 percent in 1996
(0.7 probability).
Gartner, Inc. | SPA-00-7425SPA-401-068SPA-401-070SPA-401-167SPA-ARCH-259SPA-200-126 Page 3 of 5Note 1
Benefits of Service-Oriented Configurations
■ Enables sharing of some business logic and data I/O logic among many applications of the
same or different operating modes.
■ Automatically provides data sharing through the act of logic sharing.
■ Shields the developers of mode-specific and application-specific presentation, flow control and
business logic from having to know how the back-end service functions are coded.
Acronym Key
C/S Client/server
EDI Electronic Data Interchange
GUI Graphical user interface
I/O Input/output
LAN Local-area network
OLTP Online transaction processing
PC Personal computer
WAN Wide-area network
Page 4 of 5 Gartner, Inc. | SPA-00-7425SPA-401-068SPA-401-070SPA-401-167SPA-ARCH-259SPA-200-126GARTNER HEADQUARTERS
Corporate Headquarters
56 Top Gallant Road
Stamford, CT 06902-7700
USA
+1 203 964 0096
Regional Headquarters
AUSTRALIA
BRAZIL
JAPAN
UNITED KINGDOM
For a complete list of worldwide locations,
visit http://www.gartner.com/technology/about.jsp
© 1996 Gartner, Inc. and/or its affiliates. All rights reserved. Gartner is a registered trademark of Gartner, Inc. or its affiliates. This
publication may not be reproduced or distributed in any form without Gartner’s prior written permission. If you are authorized to access
this publication, your use of it is subject to the Usage Guidelines for Gartner Services posted on gartner.com. The information contained
in this publication has been obtained from sources believed to be reliable. Gartner disclaims all warranties as to the accuracy,
completeness or adequacy of such information and shall have no liability for errors, omissions or inadequacies in such information. This
publication consists of the opinions of Gartner’s research organization and should not be construed as statements of fact. The opinions
expressed herein are subject to change without notice. Although Gartner research may include a discussion of related legal issues,
Gartner does not provide legal advice or services and its research should not be construed or used as such. Gartner is a public company,
and its shareholders may include firms and funds that have financial interests in entities covered in Gartner research. Gartner’s Board of
Directors may include senior managers of these firms or funds. Gartner research is produced independently by its research organization
without input or influence from these firms, funds or their managers. For further information on the independence and integrity of Gartner
research, see “Guiding Principles on Independence and Objectivity.”
Gartner, Inc. | SPA-00-7425SPA-401-068SPA-401-070SPA-401-167SPA-ARCH-259SPA-200-126 Page 5 of 5You can also read
