Book Excerpt

The Essential Client/Server Survival Guide

Reprinted with permission from John Wiley & Sons, Inc.
(Chapter 2, Welcome to Client/Server Computing, pages 20 - 22)

Intergalactic Client/Server

If you're like most of us -- just starting to feel comfortable with your Ethernet departmental LAN and local database server -- you may not want to hear this: Our industry is poised for a second client/server revolution. Fasten your seat belts because this second revolution promises to be just as traumatic as the one we just went through when client/server applied a giant chainsaw to mainframe-based monolithic applications and broke them apart into client and server components.

Client/server applications stand at a new threshold brought on by: 1) the exponential increase of low-cost bandwidth on Wide Area Networks -- for example, the Internet and CompuServe; and 2) a new generation of network-enabled, multi-threaded desktop operating systems -- for example, OS/2 Warp Connect and Windows 95. This new threshold marks the beginning of a transition from Ethernet client/server to intergalactic client/server that will result in the irrelevance of proximity. The center of gravity is shifting from single-server, 2-tier, LAN-based departmental client/server to a post-scarcity form of client/server where every machine on the global "information highway" can be both a client and a server. Table 2-1 contrasts these two eras of client/server computing.

The Intergalactic Vision

-Bill Gates, Chairman
Microsoft
(January, 1995)

When it comes to intergalactic client/server applications, the imagination is at the controls. The promise of high bandwidth at very low cost has conjured visions of an information highway that turns into the world's largest shopping mall. The predominant vision is that of an electronic bazaar of planetary proportions -- replete with boutiques, department stores, bookstores, brokerage services, banks, and travel agencies. Like a Club Med, the mall will issue its own electronic currency to facilitate round-the-clock shopping and business-to-business transactions. Electronic agents of all kinds will be roaming around the network looking for bargains and conducting negotiations with other agents. Billions of electronic business transactions will be generated on a daily basis. Massive amounts of multimedia data will also be generated, moved, and stored on the network.

Obviously, what we're describing is not the Internet as we know it today -- there is a lot more to this vision than just surfing through hypertext webs of HTML-tagged information. We're talking about transaction rates that are thousands of times larger than anything we have today. In addition, these transactions are going to be more long-lived and complex. The data these transactions operate on will also be more complex and rich in multimedia content. So we're talking about the next generation of Internet technology, which we call in this book the Object Web (see Part 8). This technology will also be used on small "i" Internets -- or Intranets -- including LANs, interbusiness networks, and private wide-area networks.

What Do We Need?

• Rich transaction processing. In addition to supporting the venerable flat transaction, the new environment requires nested transactions that can span across multiple servers, long-lived transactions that execute over long periods of time as they travel from server to server, and queued transactions that can be used in secure business-to-business dealings. Most nodes on the network should be able to participate in a secured transaction; superserver nodes will handle the massive transaction loads.
• Roaming agents. The new environment will be populated with electronic agents of all types. Consumers will have personal agents that look after their interests; businesses will deploy agents to sell their wares on the network; and sniffer agents will be sitting on the network, at all times, collecting information to do system management or simply looking for trends. Agent technology includes cross-platform scripting engines, workflow, and Java-like mobile code environments that allow agents to live on any machine on the network.
• Rich data management. This includes active multimedia compound documents that you can move, store, view, and edit in-place anywhere on the network. Again, most nodes on the network should provide compound document technology -- for example, OLE or OpenDoc - for doing mobile document management. Of course, this environment must also be able to support existing record-based structured data including SQL databases.
• Intelligent self-managing entities. With the introduction of new multi-threaded, high-volume, network-ready desktop operating systems, we anticipate a world where millions of machines can be both clients and servers. However, we can't afford to ship a system administrator with every $99 operating system. To avoid doing this, we need distributed software that knows how to manage and configure itself and protect itself against threats.
• Intelligent middleware. The distributed environment must provide the semblance of a single system-image across potentially millions of hybrid client/server machines. The middleware must create this Houdini-sized illusion by making all servers on the global network appear to behave like a single computer system. Users and programs should be able to dynamically join and leave the network, and then discover each other. You should be able to use the same naming conventions to locate any resource on the network.

This is a tall order of requirements. Can our client/server infrastructure - conceived to meet the needs of the single-server Ethernet era - meet the new challenges? Is our client/server infrastructure ready for intergalactic prime time? Can our existing middleware deal with millions of machines that can be both clients and servers? We answer these questions in the rest of this book.