InformationWeek

February 22, 1999

Unix To NT Hassle-Free

Three products make transferring finished code more practical by porting Unix applications to NT architectures without recoding

By Stuart J. Johnston

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Operating Systems Resource center

s Microsoft's Windows NT makes further inroads into large enterprises, many IT managers are increasingly interested in porting existing Unix applications to run on NT--either to give their users a choice in operating systems, or to take advantage of the savings inherent in running enterprise applications on less-expensive PC hardware. By doing the development on Unix, then transferring the finished code to NT, developers can maintain a common code base where the program was first developed.

But because the underlying architectures of Unix and NT are significantly different, hand recoding of applications might well be so impractical as to be impossible. Organizations might find it easier to simply make a few minor changes, then recompile and relink apps. Wishful thinking? Think again.

Products to let customers do just that include Nutcracker from DataFocus Inc., Interix (formerly OpenNT) from Softway Systems Inc., and U/Win from Global Technologies Ltd. The most mature of these is Nutcracker, which provides a complete Unix environment--including the programmer's working environment, or shell, as well as utilities, language compilers, end-user interface tools, and extensions--on top of Windows NT Server and Workstation. Unix applications appear to be running under Unix, when really Nutcracker has translated all the Unix system calls into NT application programming interface calls.

It was Nutcracker's maturity that attracted Mark Klein, director of central engineering for Mentor Graphics Corp. The developer of electronics design automation software--applications that let engineers design and test printed circuit boards, chips, and other electronic components--has a large legacy of Unix code in the products it sells. It has no intention of abandoning Unix as its primary development environment, but the recent upsurge of NT in the server and technical workstation markets got Mentor Graphics' attention. The lower cost of workstations built on the Intel architecture, rather than on workstation vendors' proprietary chipsets, has been slowly earning customers who have moved some or all of their installed base to the commodity chip architecture. Mentor Graphics wants to offer key products on both of these platforms.

The 17-year-old company has millions of lines of Unix code in lots of products, which generated nearly $500 million in revenue in the past 12 months. So any move it made toward a new platform would have to be slow, sure, and above all reliable. "What we really wanted to do was to take our products on Unix and really let them run with the same look and feel on NT, and Nutcracker allows us to do that," Klein says. The company tested the theory on a handful of applications over three months. If his developers had needed to recode those applications by hand, Klein says, it would have taken at least a year.

"But if we'd recoded the applications, we would have had two different products, and they wouldn't have looked the same," says Klein, adding that Nutcracker lets developers keep the Unix look and feel, even though the applications are running on NT. And Mentor Graphics would have had the problem of maintaining two code bases--one on Unix and one on NT.

Mentor Graphics has ported about 2 million lines of code, and the amount of money, time, and effort saved over doing it the hard way has been "an order of 10 magnitudes," Klein says.

It hasn't been entirely painless, of course. Mentor Graphics programmers had to do some hand recoding due to quirks in the version of the C programming language that the company had been using. But after they converted the code to American National Standards Institute C, the recompiling and relinking of code went fairly smoothly.

Roland Ramjist, senior technical systems analyst in the architecture and quality-management group at Royal Bank of Canada's Dominion Securities investment-banking business unit in Toronto, ran into similar standards issues in his own Unix-to-NT porting project. But after his team converted those portions of the application that were written in nonstandard C to ANSI C, Nutcracker did the trick.

While Ramjist had a different problem to solve than Klein, he too chose Nutcracker because of the product's maturity. During the past couple of years, the bank has been merging various business banking and investment-related banking enterprises under the Dominion Securities banner. The problem: One important system that notifies securities traders when securities trading deals are completed was originally written in Unix. But as the merger of business units progressed, the traders who wanted to use strictly Unix for traders' workstations were quickly outnumbered by those who were already doing other trading tasks on NT workstations. The latter users needed to be able to perform all their trading tasks on a single workstation--one running NT.