While this is the December issue that you're reading in November, it's actually early October and we're mile-high and dry in Denver at the Microsoft PDC. In addition to the cornucopia of Windows NT 5.0 material being presented, a major part of the PDC messaging this year involves the Windows DNA Architecture. That's Distributed interNet Application for the acronym-impaired.
Maybe you recall that we discussed Windows DNA in the editor's note of December 1997. Has anything changed since then? For the most part we got it right, but it's more refined from the marketing hype of last year. Windows DNA is the official application development model for the Windows platform.
The model is three-tiered, consisting of the Presentation, Business Logic, and Data layers. The Presentation layer houses the Windows clients. These applications range from the DHTML-based thin client to the Win32-based rich client. Why not thick client? The Presentation layer simply provides the user interface to the Business Logic layer. Your clients may or may not pass through a firewall to get the Business Logic layer, but this is where your scalable server applications churn through your bread-and-butter code. The server applications will access the Data layer, which can contain your legacy information on Windows NT Servers, Unix machines (deftly covered in this issue's article by Mai-lan Tomsen), IBM mainframes, or whatever.
Windows DNA technologies include COM+ and its associated services. Building upon existing COM and MTS, COM+ services provide load balancing, events, queued components, object pooling, and more. Watch for COM+ coverage in MSJ from our very own Don Box and others. Windows NT 5.0 plans to offer services such as the Active Directory and security features such as the Public Key Infrastructure, Kerberos, and Domain Policy.
Windows DNA encompasses the entire software architecture spectrum. Microsoft provides all the OS platforms, technologies, and development tools. If you can't wait for more information, check out the whitepapers, FAQs, and other goodies at http://www.microsoft.com/business/products/webplatform/.
Also in this issue, both Matt Pietrek and Jeffrey Richter give their own perspective on the latest cool feature of the Visual Studio linker: /DELAYLOAD. This technology is one of those brilliant ideas that seems so simple. We wonder why it previously hadn't been in the language products. While we'll leave the details to the experts, basically delay loading allows an EXE to only load a DLL when code execution from that DLL is needed. Ingenious! Before delay loading existed, all implicitly linked DLLs were loaded when the executable first started.
Also in the news is the announcement of an upcoming service pack for Visual Studio 6.0. Several redistributable runtime DLLs will have bugs fixed, including MFC42.DLL, MSVCRT.DLL, and MSVBVM60.DLL. For the eventual release, stay tuned to the Visual Studio Web site, http://msdn.microsoft.com/vstudio/default.asp. In the meantime, our advice is to hold off redistributing the bits until the service pack ships.