COM+ and the Battle for the Middle Tier

by Roger Sessions

• ISBN13: 9780471317173
• ISBN10: 0471317179
• Format: Paperback
• Copyright: 2000-01-01
• Publisher: Wiley

Summary

COM+, the next generation of COM, DCOM, and MTS, is here! Now best-selling author Roger Sessions offers an unbiased introduction to COM+ and the fascinating world of Component-Oriented Middleware (COMWare). In this book, you'll learn the new features of COM+ and how it fits in with other Microsoft technologies, how COM+ compares to CORBA 3.0 and Enterprise JavaBeans, and how to plan your future N-tier enterprise applications. To demonstrate how Microsoft's middle-tier technologies are being utilized in some of today's largest applications, Sessions then presents three case studies from Dell, Silknet, and Acentris-complete with business requirements, architectural overviews, system benchmarks, and lessons learned. Whether you're an IT executive planning your company's middle-tier strategy, a programmer trying to understand the new features of COM+, or an analyst interested in the differences between COM+, EJB, and CORBA 3.0, this book is for you. Advance praise for Roger Sessions's new book: "Roger has a gift for relating the somewhat esoteric topic of distributed computing to the everyday world. COM+ and the Battle for the Middle Tier provides a fine introduction to the problems addressed by the middle tier and the solutions offered by Microsoft's COM+."- MARY KIRTLAND Program Manager, Microsoft Corp. "Although I often don't agree with Roger Sessions's opinions and conclusions, I always enjoy reading his work. This book on COM+ is no exception. Roger uses simple real-world scenarios to explain very complex concepts about distributed computing,components, and scalable transaction processing, and his frequent play on words had me laughing out loud. For those who are true believers of the Microsoft way, this book may become your bible. It certainly will provide you with plenty of arguments to defend your technology choice. For those who believe in CORBA and EJB, this book will help you understand the strong appeal that Windows NT and COM+ have. (But keep the faith and don't be swayed.)"- ANNE THOMAS Senior Analyst, Patricia Seybold Group Visit our Web site at www.wiley.com/compbooks/

Table of Contents

Acknowledgments	xi
About the Author	xiii
Introduction	xv
Part One Introduction to Component-Oriented Middleware	1	(134)
The Problems of Commerce	3	(20)
Rules of Commerce	4	(10)
Companies Need Profit	4	(1)
Individual Clients Don't Spend Much	4	(1)
Clients Spend Money Slowly	4	(1)
You Need A Lot of Clients	5	(1)
You Need A Lot of Starbucks	6	(1)
Starbucks Needs to Be Easy to Build	7	(1)
Starbucks Needs to Be Easy to Modify	7	(1)
Starbucks Needs to Support Many Client Types	7	(1)
Starbucks Must Be Dependable	7	(1)
Starbucks Is a Database-Updating Company	8	(1)
Starbucks Needs Security	9	(1)
Starbucks Depends on a Middle Tier	9	(2)
Portability Is Not a Major Issue	11	(2)
Interoperability Is a Major Issue	13	(1)
Who Cares About Starbucks?	14	(9)
Components	23	(24)
History of Components: Objects	24	(7)
Enter Components	31	(2)
Some Terminology	33	(1)
Instances	34	(2)
The Interface Boundary	36	(2)
Distributed Components	38	(5)
Naive Three-Tier Architectures	43	(4)
Transaction Processing Monitors	47	(30)
Components	48	(1)
Introducing Transaction Processing Monitors (TPMs)	48	(11)
Transactions Across Databases	59	(7)
Security	66	(4)
The TPM Security Model	70	(3)
What's Wrong with TPMs?	73	(2)
Another Voice Heard From	75	(2)
COMWare	77	(58)
Components + TPMs = COMWare	79	(2)
The COMWare Subtechnologies	81	(3)
The Component Runtime Environment	84	(3)
The COMWare Environment	87	(1)
Point of Interception Algorithms	88	(4)
Typical COMWare Problem	92	(7)
Banking Pseudocode	92	(4)
Client Scenarios	96	(3)
Instance Management Algorithms	99	(15)
Instance Pooling Algorithm	100	(1)
Just-in-Time Instiation Algorithm	101	(1)
Resource Management	101	(2)
Who Needs Instance Management Algorithms?	103	(3)
Performance versus Throughput	106	(1)
Threading	107	(1)
Life Cycle	108	(1)
State Management	109	(2)
Moving the State Out of the Instance	111	(2)
What, No State?	113	(1)
Load Balancing Algorithms	114	(6)
Transaction Boundary Management	120	(10)
Transactions Equal Methods	127	(1)
Law of Transactional Integrity	128	(2)
Transactional Flow	130	(1)
Security	130	(5)
The COMWare Proposal	131	(1)
A COMWare Compatible Component	132	(3)
Part Two COM+	135	(160)
COM+ and Friends	137	(26)
The History of Microsoft's Middle Tier	139	(2)
The MTS Vision	141	(4)
MS-DTC	145	(3)
MSMQ	148	(4)
Work Flow Issues	152	(3)
Why Use Queues?	155	(3)
Disconnected Work	155	(1)
Buffering	156	(2)
Heterogenous Glue	158	(1)
MSMQ and MS-DTC	158	(2)
MSCS	160	(1)
Windows 2000 MDCA: The Next Generation	161	(2)
COM+ Components	163	(34)
Review	164	(1)
The Distribution Model	165	(1)
The Basic Component Model	166	(1)
Working with the Interface	166	(6)
The Methods of IDispatch	172	(1)
The Methods of IUnknown	173	(5)
MIDL, Type Libraries, and Implementations	177	(1)
GUIDs and Uniqueness	178	(1)
Memory Layout	178	(7)
Instance Creation	185	(1)
Transaction Organization and Rollback	185	(5)
The COM+ Stateless Model	190	(2)
Security	192	(3)
Microsoft Terminology	195	(1)
Guidelines	196	(1)
The COM+ Runtime Environment	197	(38)
COM+	198	(1)
Microsoft Management Console (MMC)	199	(1)
Introducing Components to the COM+ Environment	200	(1)
Administering Component Runtime Characteristics	201	(20)
Security Administration	202	(4)
Transactions	206	(2)
Threads and Concurrency	208	(10)
Instance Management	218	(3)
Managing the Runtime Environment	221	(7)
Object Context	228	(1)
Useful APIs	228	(3)
Monitoring	231	(4)
The COM+ Services	235	(40)
Asynchronous/Queued Components	237	(13)
Difference between Synchronous and Asynchronous Components	241	(9)
Loosely Coupled Events (LCE)	250	(7)
Component Load Balancing	257	(13)
Distributed Component Architecture	259	(1)
Non-Load-Balanced Instantiation	260	(2)
Load-Balanced Instantiation	262	(8)
In-Memory Database (IMDB)	270	(3)
Summary	273	(2)
COM+ Interoperability	275	(20)
Client Tier Interperability	279	(8)
Middle Tier Interoperbility	287	(4)
XML in the Middle Tier	287	(1)
COM/CORBA Bridges	287	(2)
Message Queues as Bridges	289	(1)
Transaction Cooperation	290	(1)
COM/DCOM on Other Platforms	290	(1)
COMTI/Babylon	291	(1)
Database Interoperability	291	(2)
Summary	293	(2)
Part Three Competition	295	(58)
Enterprise JavaBeans	297	(40)
EJB Component Types	300	(2)
An Entity CustomerBean	302	(15)
Plugging in the Database	309	(3)
There's No Place Like Home	312	(1)
EJB as COMWare	313	(1)
Entity Beans versus COM+ Components	314	(3)
A Session CustomerBean	317	(4)
The Stateful Variant	320	(1)
The SessionSynchronization Variant	321	(1)
Comparing the Entity and Session Beans	321	(5)
Rehabilitating Entity Beans	326	(3)
Overview of EJB Beans Types	329	(1)
COM+ versus EJB	330	(2)
Language Neutrality	332	(2)
In Short	334	(3)
Corba	337	(16)
Basic CORBA Architecture	338	(3)
The CORBA Component Model (CCM)	341	(6)
Component Implementation Definition Language (CIDL)	343	(1)
The CCM Basic Architecture	344	(2)
The CCM Extended Architecture	346	(1)
CCM/EJB Bridges	347	(2)
The Two Models	349	(1)
COM+ versus CCM	350	(2)
Conclusions	352	(1)
Part Four Case Studies	353	(52)
Silknet: Treating Customers as People	355	(20)
Company Profile	355	(1)
Products/Tools Used	355	(1)
Application	356	(3)
Enterprise Relationship Management	359	(1)
eBusiness Requirements	360	(2)
eBusiness Architectural Overview	362	(9)
Varied Client	363	(1)
Ease of Deployment	363	(2)
Scalability	365	(2)
Asynchronous Messaging	367	(1)
Publish and Subscribe	368	(2)
Vendor Neutrality	370	(1)
Security	370	(1)
System Benchmarks	371	(1)
Lessons Learned	371	(1)
Silknet and Microsoft	372	(1)
Some Drawbacks	373	(2)
Dell: Commerce on the Cheap	375	(14)
Company Profile	375	(1)
Products/Tools Used	375	(1)
Application	376	(1)
Dell's Internet Strategy	377	(1)
Requirements	378	(1)
The Dell Internet Architecture Overview	378	(2)
Cost per Transaction	380	(2)
System Benchmarks	382	(1)
Lessons Learned	383	(2)
Dell and Microsoft	385	(1)
Drawbacks	386	(1)
Wrap Up	386	(3)
Acentris: Transactional Gusto	389	(16)
Company Profile	389	(1)
Products/Tools Used	389	(1)
Application	390	(2)
Business Requirements	392	(2)
Architectural Overview	394	(5)
System Benchmarks	399	(1)
Lessons Learned	400	(1)
Acentris and Microsoft	400	(1)
Drawbacks	401	(1)
Wrap Up	401	(4)
Part Five Wrap Up	405	(8)
Considering COMWare Technologies	407	(6)
Portability versus Interoperability	407	(1)
Buy a Vendor, Not a Technology	408	(1)
Vendor Longevity	408	(1)
Vendor Commitment	409	(1)
Platform	409	(1)
Skills	410	(1)
Maturity	410	(1)
Throughput	410	(1)
Cost per Transaction	411	(1)
Religion	411	(1)
Try Before You Buy	411	(1)
Wrap Up	412	(1)
Glossary	413	(14)
Additional Resources	427	(4)
Index	431