Netscape Communications rebuilds the World Wide Web
Ben Smith
The threads that form the Internet hang like cobwebs, reaching out to connect this tenuous community of people and resources. Tools for finding and retrieving information and for contacting and communicating with the systems and users differ greatly, reflecting their varied origin. Each has its own purpose, interface, operations, and syntax. Most of the tools are command-driven.
Mosaic was designed and built by Marc Andreessen and a team at the University of Illinois at Champaign/Urbana-hosted NCSA (National Center for Supercomputing Applications). It is the first Internet interface that combines the hypertext browsing of WWW (World Wide Web), the file retrieval of ftp, and numerous image viewers under one GUI. (For more information, see "Mosaic: Be
yond Net Surfing".)
The NCSA Mosaic browser not only runs on Unix workstations but also--and more important--on Windows PCs and Macs. Conceptually, it has what is needed to make a commercial Internet resource palatable enough to be marketable. When it was first shown to the public, Mosaic was an instant success. Now Andreessen and most of the team have rebuilt NCSA Mosaic so that it is industrial strength and commercial grade. It is called
Netscape
.
Fast, Friendly, and Free
Mosaic primarily works with HTTP, the core of WWW. HTTP is the result of an effort initiated primarily through CERN, the European Particle Physics Laboratory in Geneva, Switzerland. The servers don't need to be supercomputers; any Unix system will suffice, and there are now servers for operating systems such as Windows NT and even DOS. Mosaic clients, often called browsers or viewers, can be as simple as a PC running Windows.
Traditionally, the performance bottleneck has bee
n the connection between servers and clients. NCSA Mosaic was intended to be a prototype, a proof of concept. It was developed for networks providing 10-Mbps or better, not your typical connection to the Internet. The reasons for this high bandwidth requirement are Mosaic's computing and communications model and its appealing incorporation of digital multimedia elements.
Like most Internet utilities, the development of NCSA Mosaic virtually stopped at the conceptual level. As a result, most of the attempts by commercial software publishers to clean it up and make an efficient, robust commercial product of it have not eliminated its basic design flaws.
Netscape Communications, a company formed from most of the original Mosaic team and under the business tutelage of Jim Clark, founder of Silicon Graphics, has changed Mosaic from the bottom up. While maintaining conformance with WWW structures and existing servers, it has completely rewritten the Mosaic browser/viewer as well as the HTTP server. T
he products are Netscape (the browser/viewer) and Netsite (the server).
A Better Browser
Netscape is both visually more appealing and operationally more functional than the original NCSA Mosaic. The labeled buttons across the bottom of the main window have been replaced with iconic buttons at the top. Menus are easier for the novice to learn because they follow common models (e.g., the leftmost drop-down menus are File and Edit).
The File menu is much simpler--only nine items. The important selections that were part of NCSA Mosaic's 16 File operations have been distributed over new drop-down menus. For example, the Reload and Refresh menu items now reside in a drop-down menu called View, along with a handy function for people developing documents for WWW--Source, a separate window for viewing the HTML (Hypertext Markup Language) source code of the current page.
The Preferences screen incorporates some of the fine style of the NextStep user interface. Through it, you
can configure your browser in nearly 50 ways, but without having to hand-edit a complex configuration file.
Many of the technical-information displays can be turned off to give a less-cluttered look. Netscape Communications' viewer/browser has been carefully designed for the nontechnical user rather than for computer scientists, engineers, and physicists. However, the improved user interface is not nearly as important as the performance improvements.
Without requiring anything different from the httpd server, Netscape has not only made the document-retrieval process faster by a factor of 10, it also makes the apparent speed (for the user) instantaneous. The goal was to bring the optimum bandwidth requirements down from 10-Mbps Ethernet speed to a level that is more realistic for the majority of Internet connections: 14.4 Kbps--that of a PPP or SLIP connection over voice phone lines.
By displaying part of the document before its transfer is complete, there is an improvement in perceived p
erformance. But there are some real performance improvements as well, achieved through a trimmer screen layout, better network communications libraries, automatic caching of previous pages, and streaming and compression techniques built into the client.
Perhaps the most amazing thing about Netscape is the price. It's free for noncommercial users, just like the original NCSA Mosaic.
Industrial Strength
If the browser/viewer is free, how does the company expect to make any money? The answer lies in its servers, replacements for the complex-to-install-and-configure, ubiquitous httpd. Netscape Communications has two versions: Netsite Communications Server and Netsite Commerce Server. The first of these is simply a more robust and efficient httpd, one for which you can get technical support.
Unlike many other WWW servers, it doesn't require that your server already be attached to the Internet to access documentation. In fact, you can easily set up a private web for distr
ibuting information in your organization.
The efficiency that Netsite includes is one that any commercial-grade WWW information provider is going to need: a better computing model that scales well to heavy request loads and client connections. The generic httpd required a new process for every WWW data request. The creation and destruction of processes and communications sockets are heavy burdens on the operating system. This load may not be noticeable when there are only a few every second, but if the requests are dozens or even hundreds a second, any system is going to be brought to its knees.
Netsite servers use a different model, where a configurable number of server processes are always running. Because they all use shared libraries (the operating system must support this), the server processes use less total memory than in other popular servers. The server also has built-in routines for handling image components of HTTP communications.
While it is common practice to extend WWW serve
rs with external scripts and executable programs using WWW's CGI (Common Gateway Interface), frequent requests to these external programs can result in the same kind of system overload as spawning a new process for each new request. Netsite servers are designed to have these extensions run under the same process as the server through the use of dynamic program module loading.
The design criteria for Netscape Communications' WWW servers are focused on providing the greatest number of services with the least impact on the server's system resources. Many of the system requirements have only recently become available on modern Unix systems and won't be realizable on older systems that have no support for dynamic loading and shared libraries.
Commercial Grade
The second version of the server, Netsite Commerce Server, has a special strength--secure communications and server authentication. This lets commercial Internet service providers and their customers carry on secure transa
ctions over the Internet.
The Netsite Commerce Server is Net-scape Communications' most important product because it offers the basic requirements for secure transactions over the otherwise open-for-snooping-and-spoofing Internet. The authenticated and secure communications link is achieved as a wrapper (using RSA encryption and digital signatures) to the client/server communications. The underlying server and client protocols remain the same.
The design is similar to PGP (see "Pretty Good Privacy" in the July 1994 BYTE) in that a signature is verified through a public key retrieved from a trusted source. Once verified, the key transmitted from the server to the requesting client is used to encrypt and decrypt subsequent communications in the session. The Commerce Server requires Netscape as its client.
One important difference, particularly for video and sound, between the algorithms used in PGP and the Netsite Commerce Server is that Netscape Communications' encryption is streaming, and
PGP requires block transmissions. Any commercial transactions that take place through this link must rely on the same vendor/customer trust used in credit-card purchases over the phone. At least the communications link is secure, unlike voice links made with portable and cellular phones.
Netscape Communications is in the process of writing the API for linked extensions to both its servers, as well as HTML document authoring tools that will help in creating page layouts as well as allowing dynamic image and text editing.
Netscape Communications may not be able to clean out the loose threads and cobwebs of the Internet, but its client and servers are the kinds of products the Internet needs to make the transition from being a cobweb of experimental projects to a serious commercial marketplace.
ABOUT THE PRODUCTS
Mosaic Netscape FREE for noncommercial users
Mosaic Netsite CommunicationsServer $1495 introductory,
$5000 list
Mosaic Netsite Commerce Server $25,000
Netscape Communications Corp.
650 Castro St., Suite 500
Mountain View, CA 94041
(415) 254-1900
fax: (415) 254-2601
screen_link (109 Kbytes)
Not only does Netscape Communications' Netscape look better than NCSA Mosaic derivatives (left), it is faster. With only a 14.4-Kbps connection, you can get the apparent performance of Ethernet.
Ben Smith is a consultant, former BYTE Lab testing editor, and author of UNIX Step-by-Step (Hayden Books, 1990). You can reach him on the Internet at
ben@ronin.com
or on BIX as "bensmith."
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