Client/Server Survival Guide

by Robert Orfali, Dan Harkey, Jeri Edwards

Overview

The #1 Client/Server book, now completely updated and expanded!

"It's savvy, informative, and entertaining as anything you are likely to read on the subject. Client/server isn't one technology but many- remote SQL, TP, message-oriented groupware, distributed objects, and so on. Like the proverbial blind man feeling the elephant, most of us have a hard time seeing the whole picture. The authors succeed brilliantly in mapping the elephant."-John Udell, Byte, "Winner, JOLT Product Excellence Award."-Software Development

"The scope and depth of topics covered in the Guide, with its straightforward and often humorous delivery, make this book required reading for anyone who deals with computers in today's corporate environment."-Bob Gallagher, PC Week

"Absolutely the finest book on client/server on the market today. It's got great advice, and is well written and fun to read."-Richard Finkelstein

The critics agree-this is the best source for anyone looking to understand and make informed decisions about client/server technology. In this Third Edition of their award-winning book, authors Orfali, Harkey, and Edwards combine detailed technical explanations with their unique brand of offbeat humor, clever cartoons, controversial soapboxes, and witty quotes to inform, educate, and entertain.

This information-packed Survival Guide takes you on a sweeping tour of the world of client/server. From operating systems and communications, to application servers that incorporate database, transaction processing, groupware, and objects, to the Internet and the World Wide Web and their role in the new generation of client/server and object management, this book covers it all.

In their other lives: Robert Orfali and Dan Harkey head San Jose State University's Client/Server and Distributed Objects Master's program and lab. Dan also works for IBM as a distributed objects consultant. Jeri Edwards is Vice President of Strategy and Product Planning at BEA Systems.

Wiley Computer Publishing Timely. Practical. Reliable.

Visit our Web site at www.wiley.com/compbooks/

Product Details

ISBN-13:	9780471316152
Publisher:	Wiley
Publication date:	02/08/1999
Edition description:	REV
Pages:	800
Product dimensions:	7.40(w) x 9.12(h) x 1.39(d)

About the Author

ROBERT ORFALI, DAN HARKEY, and JERI EDWARDS have co-authored many bestselling books including Client/Server Programming with Java and CORBA, Second Edition, Instant CORBA, 3-Tier Client/Server at Work, and The Essential Distributed Objects Survival Guide.

Read an Excerpt

Chapter 9: NOS: Meet the Players

Choosing a NOS can seem like part blind luck, part mysticism-just like the feeling when you step into a casino. The NOS newcomer must learn the rules of each network offering and discover which vendor requires the steep ante, which game is most likely to pay off at high odds, and which best suits the situation. -- PC Magazine

In this chapter, we first look at NOS technology and market trends. Next, we briefly introduce you to the key players. Then, we go over the OSF's Distributed Computing Environment (DCE) in some detail. DCE is important because it provides a comprehensive NOS solution for integrating multivendor servers in enterprise client/server environments. In the mid-90's, DCE was the archetypal example of an intergalactic postmodern NOS; it represented the best-of-breed NOS technology of the time. DCE was designed from scratch to become the "mother of all NOSs." Today, elements of DCE can still be found in most Unixes. In addition, NT 5.0 is built on top of the DCE RPC and security services. IBM also uses DCE as the foundation for its directory and security services. However, today the "mother of all NOSs" is the Internet-not DCE. So we will conclude this chapter by looking at the remaining elements of the Internet's NOS technology. We cover the Internet as a client/server application platform in Part 8.

NOS TRENDS

We already discussed server OS trends in Part 2. Here's our take on where NOSs are heading:

• NOS functions are being subsumed by server OSs. The early NOSs, like NetWare 3.X and LAN Manager, were mainly in the business of providing shared file and printer access to DOS client machines. However, the newer server OSs - such as NT 5.0, NetWare 5.0, and various Unixes - are now bundling the NOS functions in the OS. For example, most server OSs now bundle a Web server, global directory, proxy server, and support for Internet security - including SSL, IPSec, and digital certificates.

• NOSs are becoming intergalactic. NOSs are transcending their LAN origins and are now extending their global reach to include the enterprise, intranets, extranets, and the Internet.

• Global directories are becoming strategic. In the age of intergalactic networking, companies without a global directory will be at a disadvantage. We learned from the Internet just how painful life can be without one. The competing global directories include Novell's NDS, Banyan's Universal StreetTalk, DCE, Netscape's Directory Server, and NT 5.0's forthcoming Active Directory. The next big challenge is to get these directories to interoperate, which is where X.500 and LDAP will play a big role. It will help customers create federations of loosely-coupled directories.

• ORBs will subsume the NOS and expand their scope. In a sense, ORBs are the new NOSs. It's not surprising that both CORBA 3.0 and COM+ are creating competing object interfaces on top of traditional NOS services - including directories, events, MOMs, publish-and-subscribe, RPCs, and system management. Of course, ORBs extend the reach of the NOS deep into the application space, so they're much more than just NOSs (we cover ORBs in Part 7).

• NOSs are becoming turn-key commodities. NOSs are being delivered as "Shrink- wrap" software in the form of commodity server OSs. They are becoming increasingly easier to install, use, and maintain.

• NOSs are becoming multiplatform and Internet-savvy. As you will see in the next section, a NOS is more than just an extension of the local OS. In the age of the Internet, the NOS itself must be multiplatform. DCE started this trend. Next, Novell ported its best-of-breed NDS directory to other OS platforms - including Unix and NT. Netscape went even further when it introduced a whole suite of multiplatform Internet NOS offerings; Netscape doesn't even own an OS. Finally, there is Java; it provides a multiplatform OS on top of the OS. So the NOS is also becoming a vehicle for packaging turn-key Internet services and related middleware.

In summary, the NOS-which has been with us since the earliest days of client/server computing-is continuously reinventing itself. More on this in the next section.

THE PLAYERS

Figure 9-1 shows the three groups of vendors who are competing to provide next generation's intergalactic NOS. Figure 9-2 shows the technology each of these players bring to the party. Here's what these players have to offer:

1. The Unix/NOS vendors. As we explained in Part 2, the Internet was originally built on top of Unix servers. Unix provided the core NOS technology that became the foundation for the Internet-including TCP/IP, IP routing, sockets, NFS, FTP and the NIS-based domain name service. And, from the very start, Unix was built as a client/server enterprise NOS. It incubated new intergalactic technologies such as DCE and the Sun ONC + alternative.

2. The PC LAN/NOS vendors. The PC departmental NOS has been with us since the earliest days of client/server computing. NetWare, NT, and OS/2 are running millions of PC networks. They have almost become turn-key applications and are very familiar to millions of network specialists. So it shouldn't come as a surprise that the NOSs have set their sights on the intergalactic market. This is

   (Figure 9-1: The Intergalactic NOS Players.)

   (Figure 9-2: Intergalactic NOS: Where the Technology Comes From.)

   where the growth is. The LAN NOSs had to be completely re-architected to take on the Internet. The flat address spaces of the NetWare 3.X bindery and NT domains were replaced with NDS and the NT 5.0 Active Directory. The new PC NOSs now support TCP/IP natively and are starting to support Internet security protocols - like X.509 certificates, SSL, and firewalls. These NOSs now all come with a standard Web server. We don't want to turn this into a Soapbox. But, if you think about it, the LAN/NOS vendors are really playing catch-up. They are at least a year behind their competition - the Unix NOS vendors and Internet NOS providers. Instead of innovating, they are simply imitating. They are using their PC-friendly packaging technology to get their intergalactic NOSs to the mass market starting with their installed base.

3. The Internet/NOS vendors. These vendors provide multiplatform NOS products specifically designed for the Internet, intranets, and extranets. This is where most of the innovation is currently taking place. The premier vendor of Internet NOS products is Netscape (now AOL). This is the company that popularized Web browsers, HTTP servers, LDAP directories, SSL security certificate servers, and CORBA IIOP for the Internet. JavaSoft is another company that is innovating in this space with its portable OS and mobile cde system. Finally, there is a ton of Internet/NOS niche players that offer add-on products in this space. Typically, these are best-of-breed products that run on multiple OS platforms. For example, VeriSign offers a Certificate Authority framework, Check Point has firewalls, TIBCO, BEA, and Vitria provide publish-and-subscribe, Inprise provides a Java/IIOP ORB, and Cisco provides IPSec VPNs. At the end of the day, you have a very impressive set of OS-independent technologies. This is how the Internet is being developed.

In summary, the intergalactic NOS is still under construction. The good news is that all the NOS vendors (even Microsoft) seem to be converging on open Internet standards such as LDAP, X.509, and SSL. As you will see in later sections, the NOS is being encapsulated in a layer of ORB-based middleware; it promises to make you independent of the underlying OS and NOS. More on this in Part 8....

Table of Contents

THE BIG PICTURE.

Your Guide to the New World.

Welcome to Client/Server Computing.

Client/Server Building Blocks.

The Road to Bandwidth Heaven.

CLIENTS, SERVERS, AND OPERATING SYSTEMS.

Clients, Servers, and Operating Systems.

The OS Wars: Meet the Players.

BASE MIDDLEWARE: STACKS AND NOSs.

NOS: Creating the Single-System Image.

RPC, Messaging, and Peer-to-Peer.

NOS: Meet the Players.

SQL DATABASE SERVERS.

SQL Database Servers.

SQL Middleware and Federated Databases.

Data Warehouses: Information Where You Want It.

EIS/DSS: From Queries, To OLAP, To Data Mining.

Database: Meet the Players.

CLIENT/SERVER TRANSACTION PROCESSING.

The Magic of Transactions.

TP Monitors: Managing Client/Server Transactions.

TP-Lite or TP-Heavy?

TP Monitors: Meet the Players.

CLIENT/SERVER GROUPWARE.

Client/Server Groupware.

Groupware: Meet the Players.

CLIENT/SERVER WITH DISTRIBUTED OBJECTS.

Distributed Objects and Components.

CORBA: From ORBs to Enteprise Beans.

COM+: The Other Component Bus.

Object Databases.

Distributed Objects: Meet the Players.

CLIENT/SERVER AND THE INTERNET.

Web Client/Server: The Hypertext Era.

Web Client/Server: The Interactive Era.

Web Client/Server: The Distributed Object Era.

Web Client/Server: Meet the Players.

DISTRIBUTED SYSTEM MANAGEMENT.

Client/Server Distributed System Management.

Distributed System Management Standards.

BRINGING IT ALL TOGETHER.

Client/Server Tools and Application Development.

Which Way Client/Server?

Where to Go for More Information.

Index.

Preface

Client/Server: The Perpetual Revolution
Client/server computing has created a deep paradigmatic shift in our industry. It's replacing monolithic mainframe applications with applications split across client and server lines. The client-typically a PC-provides the graphical interface, while the server provides access to shared resources-typically a database. Distributed objects and the Internet are a paradigm shift within a paradigm shift; they're a new client/server revolution within the client/server revolution. Objects break up the client and server sides of an application into smart components that can play together and roam across networks. The Java Web is the killer application that is delivering objects to the masses. The combination of distributed objects and the Web (or the Object Web) is reinventing client/server computing.

Why Another Revolution?
So why is there another client/server revolution when the first one is still in full swing? The answer-as usual-is newer and better hardware and the demand for applications that match the new hardware. The first client/server revolution was driven by new hardware; PCs and Ethernet LANs forever changed the way we interact with our applications. Gone are the green-screen uglies associated with terminal-attached mainframes. Instead, we have GUIs. There's no way to turn back the clock.

The second client/server revolution is also fueled by advances in hardware. This time, Wide Area Networks (WANs) are breaking the proximity barriers associated with Ethernet LANs. Millions of us are getting a firsthand taste-thanks to the Internet-of the joys of intergalactic networking. We will soon want alot more. We won't be satisfied with just navigating through information and chatting; we will want to conduct our business on these networks. People will either transact directly or through their electronic agents. Money is already changing hands on the Web. In the age of intergalactic transactions, there's no going back to single-server, departmental client/server LANs. The Java Web has changed that forever. So, the second era of client/server is driven by very high-speed, low-cost, wide-area bandwidth. The telephone companies and WAN providers are getting ready to unleash almost unlimited bandwidth-they're wiring the entire planet for fiber-optic speeds.

The Object Web
We may soon have millions of servers interconnected across the planet at 10 times LAN speeds. This is the good news. The bad news is that our existing client/server infrastructure is geared for single-server departmental LANs; it cannot cope with the new intergalactic demands-millions of servers and applications that can spawn trillions of distributed transactions. Three-tier client/server solutions using distributed objects and the Web-or the Object Web-are our only hope for dealing with the new infrastructure requirements. Distributed Web objects such as JavaBeans, CORBA Beans, Enterprise JavaBeans, and COM+ components are changing the way we architect, develop, package, distribute, license, and maintain our client/server software. A new breed of Object Transaction Monitors (OTMs) built on top of object request brokers, TP Monitors, and the Internet promise to provide the ultimate middleware for running these Web-based components.

We Live in Uncertain Times
A paradigm shift is akin to a revolution: Dominant structures crumble, vacuums are created, and the world is in turmoil. The transition period is marked by confusion, deep uncertainty, and exhilaration. Confusion is the result of seeing familiar bedrock structures disappear. Uncertainty comes from not knowing what the next day will bring. And the exhilaration comes from realizing the new possibilities that are created by the new paradigm. Client/Server Survival Guide, Third Edition is our attempt to understand this revolution. The emerging 3-tier client/server paradigm is fielding a lineup of competing technologies, each vying to become the new emperor. We hope the new emperor will have clothes.

And We Can't Turn Back the Clock
Before we tell you all about this book, let's answer some questions that we've been wrestling with: Is intergalactic client/server just a passing fad? Is the Object Web a figment of the imagination? Can things go back to the way they were? We're the first to admit that client/server and the Web have become the industry's most overhyped and overloaded terms, but it's not a passing fad. This is because the world is populated with more than 150 million networked PCs that need to be served in the style they expect. The Web is the application; distributed services everywhere extend the client's universe. And in the age of the Internet, this service must be provided on an intergalactic scale. Servers are expected to do a lot more work for their Web-based clients. Client/server computing is unabashedly network-centric, and there's no turning back the clock. Yes, the revolutionary chaos of the client/server world may make some of us yearn for the good old days, but the time machine only marches forward.

What This Survival Guide Covers
This Survival Guide explores client/server computing from the ground up. It consists of 10 parts; each one can almost be read independently. We'll give you a short description of what the parts cover. If you find the terminology too foreign, then by all means read the book to find out what it all means.

Part 1 starts with an overview of what client/server is and what the fuss is all about. We develop a 3-tier client/server model that will serve as a map for the rest of the book. We go over the state of the client/server infrastructure to get a feel for how much of it is already here, and what remains to be built. We take a close look at how much bandwidth we can expect, and when.

Part 2 examines the client/server capabilities of our current crop of operating systems including Windows 98, NT 5.0 (or Windows 2000), Mac OS X, Linux, Unixes, OS/2, and NetWare 5.0. We feel like war correspondents covering the battlefield of the operating system wars. We also look at how Internet appliances, shippable places, and Webtops are changing the client landscape.

Part 3 explores the NOS and transport middleware substrate. We take a look at communication stacks, RPCs, MOMs, event channels, publish-and-subscribe, global directories, Kerberos security, and single logon. The Internet is becoming the mother of all NOSs. Consequently, we go over Internet NOS technology such as LDAP directories, X509v3 digital certificates, public/private keys, Secure Electronic Transactions (SET), IPSec, SSL, S-HTTP, VPNs, and firewalls.

Part 4 explores the very popular database server model of client/server. We cover SQL-92, SQL3, ODBC, JDBC, SQLJ, OLE DB, ADO, DRDA, stored procedures, and triggers. We spend a lot of time looking at new database technologies such as data warehouses, data marts, OLAP, ROLAP, HOLAP, data mining, and data replication. We also cover products in all these areas.

Part 5 explores the TP Monitor model of client/server. We cover the different transaction types including flat transactions, sagas, nested transactions, chained transactions, and long-lived transactions. We bring you up-to-date on what's happening with TP Monitors. Then we dive into the great debate that's pitting the TP Lite model offered by the database servers against the TP Heavy model offered by TP Monitors. We explain why TP Monitors are needed in a world dominated by database servers.

Part 6 explores the groupware model of client/server. We look at the world of Lotus Notes, Exchange, Collabra, GroupWise and interpersonal applications.We look at workflow and e-mail Internet standards such as Wfmc, SWAP, jflow, SMTP, IMAP4, POP3, and S/MIME. Groupware shows us what client/server can really do-its paradigm goes much further than just recreating mainframe-like applications on PCs.

Part 7 explores the distributed-object model of client/server. We explain the role of Object Request Brokers (ORBs), such as CORBA, RMI, and DCOM. We explain how objects are packaged as components. We look at client-side component models such as ActiveX and JavaBeans. We also look at the new server-side components models including Enterprise JavaBeans, CORBA Beans, and Windows 2000 or NT 5.0's COM+. Finally, we look at a new generation of Object Transaction Monitors (OTMs) such as BEA's M3, Oracle's Application Server 4.0, IBM's Web-Sphere/Component Broker, and Microsoft's MTS that act as server-side component coordinators. We explore how objects, components, and OTMs can be used to create a new generation of client/server information systems.

Part 8 explores the Internet from a client/server perspective. We start with the Web as we know it today. Then we look at Java objects and new Web compound document standards such as XML, DOM, and XSL. Finally, we look at how distributed objects, components, and the Web are morphing into a new Object Web. This is real revolutionary technology that's going to completely overhaul the way we build client/server systems.

Part 9 is about how to manage client/server applications. The biggest obstacle to the deployment of client/sever technology is the lack of integrated system management platforms. Fortunately, the situation is changing. We will look at new Web-based frameworks that may help us manage our distributed applications. We also cover system management standards, such as SNMPv3, MIB, RMON2, CMIP, DMI, CORBA, X/Open, WEBEM, CIM/XML, and JMAPI.

Part 10 is about how to design, build, and deploy 3-tier client/server applications. We look at what tools can and cannot do for you. This part ends the survival journey and ties all the pieces together.

What's New in This Edition?
We thank the 90,000 readers of our second edition for continuing to make this book a bestseller. As a result, our publisher asked us to do another "minor" update to bring the book up-to-date. As usual, we discovered that there's no such thing as a minor update in the client/server field. Time is measured in dog years. Almost everything in the book had changed. So the minor upgrade became another eight-month effort. The result is this new book. Over a third of it is entirely new material. Almost every page in the old book was updated. It was an amazing amount of work. We pity the practitioners of client/server because the field is a moving target; it takes a certain amount of stability to develop applications. We also pity the readers of our first edition because you must now read an entire new book. There are no shortcuts. Of course, we kept some of the old cartoons. The Martians appear to be timeless.

How To Read This Book
As we recommend in all of our books, the best way to approach this Survival Guide is to ask your boss for a one-week, paid sabbatical to go sit on a beach and read it. Tell him or her that it's the cheapest way to revitalize yourself technically and find out all there is to know about client/server technology, which now covers almost the entire computer science discipline. Once you sink into that comfortable chair overlooking the ocean, we think you'll find the book a lot of fun-maybe even downright relaxing. You won't get bored; but if you do, simply jump to the next part until you find something you like. You can jump to any part of the book and start reading it. We recommend, however, that you carefully go over the cartoons so that you have something to tell the boss back at the office.

What Are the Boxes For?
We use shaded boxes as a way to introduce concurrent threads in the presentation material. It's the book version of multi-tasking. The Soapboxes introduce strong opinions or biases on some of the more controversial topics of client/server computing. Because the discipline is so new and fuzzy, there's lots of room for interpretation and debate-so you'll get lots of Soapboxes that are just another opinion (ours). The Briefing boxes give you background or tutorial type informa-tion. You can safely skip over them if you're already familiar with a topic. The Detail boxes cover some esoteric area of technology that may not be of interest to the general readership. Typically, the same readers that skip over the briefings will find the details interesting (so you'll still get your money's worth). Lastly, we use Warning boxes to let you know where danger lies-this is, after all, a Survival Guide.

Who Is This Book For?
This book is for anybody who's associated with the computer industry and needs to understand where it's heading. We are all involved with client/server technology in some form or another-as users, IS managers, students, integrators, system developers, and component developers. All new software is built using some form of client/server technology.

We hope you enjoy the reading, the cartoons, and the Soapboxes. Drop us a line if you have something you want to "flame" about. We'll take compliments too. We're relying on word-of-mouth to let people know about the book, so if you enjoy it, please spread the word. Finally, we want to thank you, as well as our Martian friends, for trusting us to be your guides.