Porting tools ease migration to Windows NT
- By Cheryl Gerber
- Apr 12, 1998
Although far from a cure-all, application porting tools have emerged as a salve for some of the pains that agencies develop when managing mixed Unix and Windows NT environments.
Porting tools help users either integrate off-the-shelf Windows NT software with Unix platforms or migrate Unix applications to Windows NT platforms, without rewriting programming code from scratch. Such ventures pave the way for agencies to take advantage of the lower cost and ease of use associated with Microsoft Corp.'s Windows NT environment.
But analysts and customers stress the importance of knowing when to use porting tools. "Porting tools are for people who need to buy time with a high-value, short-term fix," said Doug Lynn, an analyst with the Meta Group Inc., Stamford, Conn. "But I can't see this being attractive for home-grown applications that take advantage of platform-specific capabilities."
As Windows NT has become more common, its use has begun to spread out on networks, and users have turned to porting tools to manage this environment.
Federal agencies primarily use two toolsets: Nutcracker from DataFocus Inc., Fairfax, Va., and OpenNT from Softway Systems Inc., San Francisco.
Unisys Corp., for example, used Nutcracker to port Unix applications to Windows NT as part of the Coast Guard's Standard Workstation III contract. Dell Computer Corp. recently announced that it would bundle OpenNT with every Dell WorkStation 400 computer. Both tools aim to alleviate the need to rewrite programs to work with Windows NT's application program interfaces (APIs), which provide the links between an application and the operating system. But the tools take slightly different approaches.
Unix applications being deployed on Windows NT range in size from 300,000 to more than 16 million lines of "complex and messy source code," according to a report by Aberdeen Group, Boston. "Users can't throw out the applications, and they want to get out from under the huge burden of maintenance and expense," said Jim Hurley, an analyst with Aberdeen Group. Increasingly, users have turned to porting tools as a solution.
Nutcracker's software developer's kit (SDK) provides a Unix emulation library that mimics the behavior of basic Unix functions but actually works with Windows NT's Win32 APIs. Consequently, ported applications use Windows NT's native file systems and Dynamic Link Libraries. "Nutcracker fools the program into thinking it's still running on Unix," said Pat Higbie, chief executive officer of DataFocus.
Mortice Kern Systems Inc., Waterloo, Ontario, Canada, provided DataFocus with many of the Unix utilities for Nutcracker, including those for creating script files, automating tasks and manipulating files and text.
In contrast, OpenNT uses a Unix subsystem on Windows NT, essentially creating an encapsulated Unix environment and taking advantage of Unix system resources rather than those for Win32. Softway's tool fleshes out a basic subsystem Microsoft built into Windows NT to allow it to operate in a Unix environment. Softway worked with Microsoft to make Windows NT fully compliant with the Posix standard that underlies Unix systems.
"With OpenNT, Unix administrators can administer NT through Unix system calls," said Chris Brown, director of federal operations at Softway, Sterling, Va.
Perhaps as a result of these differences, the tools are better-suited for different kinds of users, according to systems integrator Litton/PRC Inc., which has tested and deployed both tools.
PRC's laboratories found that OpenNT is best-suited for users who want to re-create a Unix environment on a Windows NT platform. "If you have a heavily Unix environment in which code has been written to make detailed use of Unix interfaces and device drivers, then you should use OpenNT," said Jim Stanley, PRC's senior manager for systems engineering, Reston, Va.
In turn, PRC found that Nutcracker is best when the goal is a quick port of code from Unix to Windows NT. "If you have code that is not as Unix-specific, then Nutcracker is faster and easier than OpenNT, but it's not as comprehensive," Stanley said.
As an example, International Research Institute Inc. (INRI) , Reston, last year demonstrated for the Defense Information Systems Agency a Unix-to-Windows NT port of the Defense Information Infrastructure Common Operating Environment, which is the DISA-defined standard software environment for command and control applications.
"We were able to do 600,000 lines of source code porting in Unix and Windows NT in two months with Nutcracker," said Frank Engel, INRI's president and chief executive officer.
DISA was helped but not convinced. The agency is quick to emphasize that the porting approach is a short-term solution. "We need [these tools] to learn some lessons as an interim step, but what we really want is platform-independent software that uses Java," said Dawn Hartley, deputy commander of the DISA's Center for Computer Systems Engineering.
A Tool in Need
However, a number of other agencies have found a need for porting tools, using them to deal with everything from small bits of codes to full applications that are not yet available on the Windows NT platform.
The Army, for example, has used OpenNT to offload Unix network monitoring functions so that non-Unix personnel can perform basic functions on Windows NT when network managers are unavailable.
"With the way DOD is downsizing, we don't have the resources we had before," said Dave Hogue, network manager of the Army Information Systems Software Center's Software Development Center.
"A lot of the remaining people don't have Unix experience," he said.
At Lawrence Livermore National Laboratory, Livermore, Calif., the physics and space technology program uses OpenNT to port a 3-D, graphics-intensive, Unix-based Plasma Physics Simulation program to Windows NT.
Peter Vitello, a staff scientist, is using Microsoft's Visual C++ and Digital Equipment Corp.'s Visual Fortran for compilers with a public-domain graphics package called XGrafix. "OpenNT will call the Visual C++ and DEC Fortran and has its own Unix graphics libraries that speak to NT, allowing the XGrafix program to work," Vitello said.
Many customers see the tools as a way to buy time as they migrate their operations from one platform to another.
Most agencies are not ready or able to commit to complete rewrites that yield a common source-code baseline between Unix and NT. Like DISA, they need porting tools to buy time and to learn, agencies said. The tools serve as training platforms that teach developers how to work in mixed Unix/NT environments.
"We use OpenNT to transition experienced Unix users to NT," said Willie Hamm, systems administrator at the Environmental Protection Agency, Atlanta. The EPA is using OpenNT to train and transition Hamm and other heavy-duty Unix users at the EPA to use Windows NT.
Jim Hoover, a Hewlett-Packard Co. senior systems manager at the Joint Command and Control Warfare Center, Kelly Air Force Base, San Antonio, uses Nutcracker for the same purpose. "Instead of making a complete jump from Unix to NT, programmers can use their hard-earned Unix skills on the NT box to make them become productive on Windows NT more quickly," he said.
While INRI's Nutcracker port went quickly, speed of port depends on the application and the available resources.
In testing Nutcracker, the Navy's Space and Naval Warfare Systems Command found that graphics are a crucial factor. "The more Motif and X Window calls, the slower the work and the more effort is involved," said Randy South, a systems engineer with the Navy's Joint Maritime Command Information System program at Spawar.
Lawrence Livermore's Vitello chose OpenNT because its SDK is less expensive than Nutcracker's.
"Nutcracker is 10 times as much as OpenNT. It's $5,000 for the SDK, and the OpenNT is only $500," he said. However, he has had mixed experience with Softway support for OpenNT. "When I do get them, the support people are knowledgeable. But they don't tend to respond in a timely fashion," he said.
While the Nutcracker SDK costs 10 times more than OpenNT's SDK, Nutcracker prices may be lower for large enterprise deployment because Nutcracker's per-workstation plug-in price is less than half the OpenNT per-workstation plug-in price.
Standards compliance is another issue in porting tool platform applications.
"OpenNT is Posix-compliant, and Nutcracker is not totally Posix-compliant. Full Posix compliance incorporates a lot of things we don't use and some people don't care about, but it's still a mandate," Engel said.
Because Nutcracker lives on Win32 APIs, it shares Windows NT's assets and liabilities. "The Posix implementation on NT has this fatal flaw. It cannot access Win32 APIs," Higbie said.
However, Nutcracker 4.0, due this month, may compensate in some ways for that. The new release will provide support for Component Object Model, which is an object technology developed by Microsoft that lets users reuse code across multiple applications.
The new release of Nutcracker will allow developers to wrap Unix code with COM and call it from any Windows application. The idea is to make it easy to take advantage of Unix code within a Windows program.
-- Gerber is a free-lance writer based in Kingston, N.Y.
AT A GLANCE
Status: Porting tools have become a popular way to ease the migration of off-the-shelf applications, but the tools are not a complete solution.
Issues: Agencies appear most interested in using the tools to address the short-term requirements of helping Unix users adapt to the Windows NT environment.
Outlook: Good. Although porting tools do not address every problem, the technology does meet some basic user requirements.