Cover Story

Linux vs. Windows NT: Engineers Speak Out, Part 2 Few ISD editorials in recent memory have elicited stronger responses than "Why Most Engineers Insist on Unix." Here are some representative responses from readers. by Murry Shohat

In his editorial in the April issue, Editor-in-Chief Jonah McLeod discussed readers' comments on ISD's series of benchmarks and articles on Windows NT as an EDA platform, which were generally highly critical. He raised the issue of why Intel would want to push a Microsoft operating system when a robust version of Unix--Linux--is available for the PC, and he concluded with a request for readers to e-mail their opinions. Part 1 of our report on readers' responses offered a general overview and discussions of the reliability of Linux versus NT and of productivity issues (July). This, the conclusion, covers utilities, OS support, and economic questions. As in Part 1, some respondents asked to remain anonymous and those quoted speak only for themselves unless otherwise indicated.

Increasing productivity often depends on easy-to-use, customizable utilities. Unix is famous for hundreds if not thousands of productivity-enhancing code pieces. "What I see lacking in NT," says an engineer with Digital Equipment Corp.'s Engineering Research and Development unit in San Diego, "is the suite of Unix utilities."

Dan Dauer, a consulting engineer in ASIC design and development in Fort Collins, Colo., for Real3D Corp. in Orlando, Fla., agrees. "It bothers me to see well-meaning managers or project leads pushing NT boxes for engineering applications. That's like giving a master carpenter fencing pliers--the type with a small hammerhead on the side--to build a house," he says. "The job will take about twice as much time" as it would have if the carpenter had used appropriate tools.

Unix systems, Dauer explains, "facilitate the use of scripts to 'sew together' complex product development processes that tend to weave tools often supplied by multiple vendors. There's also a plethora of Unix-based tools invaluable for test benches, process automation, and design development. Tools like Perl, sed , and awk and commands like grep are used heavily by engineers and programmers but not, in general, by the point-and-click or single-application gang."

A similar point comes from Rich Abato, principal consulting engineer at Intrinsix Corp. in Nashua, N.H.: "Having suffered through the development of a simulation regression environment that had to run on both NT and Unix (Sun), I can't imagine why anyone would choose to run NT over Linux" for such purposes. Linux, he notes, "supports all popular shells and scripting languages--such as rlogin, telnet--real symbolic links, awk , grep , sed , make , m4 , rsh , nfs , cron , X Windows, and all the other bits and pieces required to develop large ASICs and FPGAs. Best of all, Linux is free!"

He continues: "Linux provides better facilities for sharing the hardware platform within a development group to run remote jobs during simulation regression runs or other work that can be split over several machines. Articles in ISD have compared the point tools running on NT with those for Unix," but further consideration should be given to the whole design environment--"design entry, source control, simulation, bug tracking, logic synthesis and timing analysis, manufacturing test generation, and the verification of design rules. Between each step, scripts and tools are required to bridge the various environments. The entire process is usually under make or script control to ensure the correctness and repeatability of the design and to simplify repetitive tasks."

Describing himself as "a real Unix bigot," an engineer in Lucent Technologies, Inc.'s Network Systems Enterprise Infrastructure Group nonetheless adds that "some day I know I'll have to face the reality" of NT's eventual triumph. "I've been worried about this NT-Unix thing for a while. What will I do on NT? I'm a power user, hungry for computing power to verify ASICs. Unix provides scripting, batch operations, job control, remote access, and so forth." According to him, OpenNT, from Softway International, Inc. in San Francisco, "may be the best of both worlds. It's a Unix environment that lives on top of Windows NT."

Another issue, portability, is stressed by James P. Walsh, a senior member of the technical staff at Rockwell International Corp.'s Electronic Commerce Business Unit in Wood Dale, Ill. "My personal vote is for Linux!" In his experience, "applications written for HP or Sun can be ported very easily. I've ported all of the Sun tools we developed in-house to run on Linux. Generally it required only a recompilation." On the other hand, he says, "porting EDA applications from Unix to NT is not a simple task." Designers who have to run the kinds of office productivity applications in Microsoft Office, he argues, should "use WABI--developed by Sun and ported by Caldera [www.open.lv/products/caldera/products/wabi.html] to run under Linux. WABI allows Windows apps to run on a Linux box."

Laments Michael Strain, an instrumentation engineer at the University of Oregon's Institute of Molecular Biology in Eugene who uses Linux on his PC to manage a group of Silicon Graphics and Sun workstations, "If only there were Linux versions of the more sophisticated application software typically used on PCs--word processing, spreadsheets, desktop publishing, CAD/CAE, and so forth." Indeed, he isn't alone in this complaint: Many people are clearly troubled by the lack of small-office/home-office suites that run under Linux. The solution is often a dual-boot configuration, usually with Windows 95 rather than NT as the second OS.

Performance isn't productivity
For many companies, however, dual booting isn't a worthwhile option, because, for example, it's impossible to stop a simulation under Linux to write a memo under Windows. On the other hand, most companies would prefer not to give engineers two computers--one for office automation apps, the other for engineering.

"We're struggling with if, when, and how to eliminate [one of the] two computer boxes on each engineer's desk," Steven Paluzzi, a senior CAE tools engineer at Picturetel Corp. in Andover, Mass., writes. "The economies of PCs--especially if they do e-mail, word processing, Web browsing, and EDA tasks--are attractive, but not at the cost of productivity." Benchmarks, he notes, measure performance but not productivity.

"We can always figure out how to get out of a problem in Unix by running tools," he explains. "Most of the time we do it quickly; sometimes it takes a few hours. NT problems are virtually impossible to trace and fix. Many times the problems can't even be repeated. That's unacceptable, especially when you run hours or days of simulations.

"The economics of PCs--especially if they do e-mail, word processing, Web browsing, and EDA tasks--are attractive, but not at the cost at productivity," says Steven Paluzzi, senior CAE tools engineer at Picturetel.

"These days I'm converting Sentry test vectors from an old LSI design into new Verilog simulation test vectors. I have many files, directories, and scripts. I wouldn't even know where to begin this task on an NT machine." "Chief among the reasons not to use NT," Paluzzi contends, is the absence of any "simple way of massaging data between tools, which I can easily do with shell scripts and/or Perl. Having no powerful command line interface and tools renders me much less productive."

The same point is stressed by Doug Hahn, an ASIC design engineer at Nvidia Corp. in Sunnyvale, Calif. "Engineering requires a great deal of command line interface work as opposed to GUI work," he notes. "The only command line interface on NT is either DOS or a third-party X Terminal tool, usually hooked up to a Unix box anyway. I really don't want to have to switch from the command line to the GUI because of the OS."

Exemplar Explains

by Tom Feist In the fourth quarter of 1996, Exemplar ported its Leonardo and Galileo synthesis tools to Linux. Truly a pioneer on Linux, we hoped that other EDA tool vendors would follow, since an effective design environment requires software for the entire flow, including design entry, simulation, synthesis, and placement and routing. Unfortunately, none of the simulation or FPGA vendors followed our lead. During the 18 months that we offered software for Linux, we had hardly any license requests; indeed, fewer than 10 such licenses were purchased. Furthermore, with those customers, we encountered support issues caused by the fact that many versions of Linux are in use--there's no real standard. Like all companies, Exemplar must choose profitable businesses for investment. Early this year, we notified our Linux customers that we would no longer support the OS and provided several options, including moving to other, supported operating systems. We do understand that Linux offers advantages to some customers and may eventually play an important role in EDA environments. If more vendors move to support Linux, so that users can have a complete flow, Exemplar will revisit this question. Tom Feist is the vice president of marketing at Exemplar Logic, Inc. in Fremont, Calif.

Laury Flora, vice president of Octera Corp. in San Diego, is another engineer who suggests that the current infatuation with graphical interfaces may make engineers less productive. "I've noticed that many important tools concentrate on a great GUI. That ignores an important aspect of engineering: The big tools, such as Synopsys Design Compiler and Cell3, sometimes don't do what's needed. Requiring engineers to repeat every step in a complicated process reliably, even if it could be done, is doomed to failure. Good engineers quickly automate complicated processes via scripts. Windows doesn't appear to be good at this. New commands can't be added simply by creating a file of that name. The hundreds of little productivity tools that have been developed on Unix don't exist in Windows. That's why I can't do my job on a Windows system."

Slowdown
"Any GUI interface would only serve to slow me down," says Rod Webster, a design engineer at UTMC Microelectronic Systems in Colorado Springs. "I find myself continually using Unix utilities piped together in various combinations and orders and with various parameters," he reports. "They allow me to wade quickly and intuitively through kilobytes of synthesis reports, simulations results, and SDF files."

"The process control Unix offers is simple, usable, and effective," he continues. "Say, for example, that you start a script but then want to stop it momentarily and check on a file before allowing it to continue. A quick Control-Z and it stops; hit F-G or B-G and it starts up again. What could be quicker or simpler? I could go further, talking about makefiles , RCS/SCCS, and other script-oriented utilities and programs that help implement automation strategies. Suffice it to say that Windows' purportedly easy-to-use GUI doesn't contribute anything to these basic EDA tasks.

"As long as the EDA vendors support Linux or FreeBSD, there can be no valid reason for pressuring IC designers into moving to Windows NT," he concludes. "Of course, that assumes that CAD groups truly serve the interests of their companies!" For Webster, "It would be tragic to see engineers change tools simply because the economies of mass marketing and volume make it cost-effective to use the lowest-common-denominator tool."

Yet another contributor emphasizing that "Unix allows you to do much more automation" than other operating systems is Wing Choy, an ASIC design engineer for a major semiconductor company in Sunnyvale, who says that he's installing Linux on a PC. He feels "very happy with Unix on a Sun workstation," hasn't previously used Linux, and has never used NT. Nonetheless, he's "dismayed by the tactics used by Microsoft to drive away the competition." If Linux turns out to be "as good and reliable as Unix and I can use it the same way I use Unix, I would definitely choose Linux. Otherwise, I would rather stick with my Sun. As a circuit designer familiar with EDA software, I know that no design can be accomplished by using EDA tools alone."

One of the few contrary views comes from Ross Swanson, a design engineer at SIS Microelectronics in Longmont, Colo., who seems to have traveled further down the NT road than most other contributors to the debate. "Those arguing that the PC doesn't have the same low-level utility tools, like sed and awk , to link the EDA flow obviously don't program in Perl. This works well enough on the PC to make it possible for me to move freely between the two platforms while developing programs."

"I like working on both my Unix machine and my PC," he adds, referring to his NT PC. "I won't mind running Synopsys DC shell on a PC. I see this fight as a win-win situation for engineers: new ways to do things, new hardware, new operating systems, new tools."

Linux support is unique
Support is another key issue. Rich Abato of Intrinsix writes that his company's engineers believe that the "support available from the user and developer community for Linux has been better than any support available from the for-profit OS developers." He notes that "the Linux community received two honors from Infoworld last year--Best Technical Support and Best Network OS--as well as the 1996 Desktop OS Award."

"The hundreds of little tools on Unix don't exist in Windows. That's why I can't do my job on a Windows system," reports Laury Flora, VP of Octera.

"I've been wondering for years why the EDA vendors, with few exceptions, have ignored Linux as a platform for EDA tools," he continues. "Porting C or C++ to Linux from other Unix flavors usually involves just a recompilation. Such performance-tuned tools as simulators using architecture-specific optimizations may require additional work, but it would still be less difficult than porting such tools to Windows NT and no more difficult than supporting Sun, HP, and DEC Alpha tools. No special code is required to deal with different end-of-line conventions, windowing systems, and disk- and file-naming conventions." Abato says that he has companywide backing for his position: "You may remove the disclaimer because my boss says he hires engineers for their opinions!"

Support for Linux may win raves from users and awards from magazines, but Linux support from EDA application vendors leaves much to be desired, complains Steven C. Schmalz, a research engineer at Eaton Corp. in Cleveland. "I've been using Linux for about three years and have always wondered why EDA companies never embraced it as an alternative platform. I currently use Viewlogic tools under NT, and I'm not impressed! In all its user friendliness, NT is so weighted down with gimmicks that my 200-MHz Pentium Pro runs no faster than a 120-MHz Pentium under Linux."

Schmalz's unit has a Linux server it uses "with great success" for system-level modeling with Mathlab and Simulink. "Mathworks is the only one of our software vendors supporting Linux," he reports. "When we asked EDA sales reps about Linux, we found that most had never heard of it! EDA companies, with their strong heritage on Unix platforms, should embrace Linux and port their tools to it."

Linux EDA
Some EDA vendors have actually done so, notes Craig Mahaney, a hardware manager at Medar, Inc. in Farmington Hills, Mich. "A number of engineers here have already converted their home Pentium systems, and we couldn't be happier. I only hope that more EDA vendors follow the lead taken by Design Acceleration, Exemplar Logic, Fintronic, Runtime Design Automation, and Zycad to produce EDA software for Linux." (A support site for such efforts has appeared on the Web at www.linuxeda.com.)

Gregory Wright, a member of the technical staff of the Wireless Technology Research Department at Bell Laboratories in Holmdel, N.J., thinks he knows why most EDA vendors have neglected Linux. "It seems that the real worry among tool vendors is not that Linux users are a small market but that supporting Linux will accelerate the trend--started by NT--of users demanding more affordable EDA tools. While some vendors see this as a threat, a few will see it for the opportunity that it is. When they do, I'll be buying their products."

Wright tells a story showing, in his words, that "some of us are willing to put our money where our mouths are. We were considering buying Exemplar's Leonardo synthesis tool for VHDL in FPGA development," he recounts. "One of the main attractions was Exemplar's support for Linux." The NT and Linux versions sold for the same price. "Without warning, Exemplar announced that it is discontinuing its Linux products. We were not pleased and have decided that we will never buy Exemplar products again." (See "Exemplar Explains.")

Russell Petersen, a VLSI design engineer at Hewlett-Packard Company's Integrated Circuit Business Division in Fort Collins, notes an unusual aspect of the support for Linux. Linux, he points out, has attracted "loads of programmers all eager to fix problems quickly. I dread the thought of being stuck with an NT bug and not being able to do a thing about it for a long time. You just have to learn to work around these NT bugs, since no real error information is available."

Joyce Clapp of Nortel Information Networks, who runs Linux at home and at work, makes a related point: When a problem comes up with Linux, "I log in as 'root' and fix it. If there's a problem with NT, what do you do? In most cases, the fix seems to be to reinstall either the app or the machine. That's sometimes necessary for Linux too, but very rarely." In Linux, "if I want to change something about the OS or the software I'm running--well, I do."

Microsoft may be trying to improve the situation, observes E. Douglas Jensen, a program manager at Mitre Corp. in Boston. Calling himself "neutral" on Unix versus NT issues, he writes that "Microsoft has been increasingly providing universities with free, albeit highly protected, NT sources and now has an annual public conference for external NT researchers--well-attended ones, I must add."

Another support issue is documentation, and here Don Parrish-Bell, an FPGA and CPLD designer at Visicom in San Diego, thinks that Windows NT has the edge. "There seems to be a motto among Unix-philes: 'We don't need no stinking manuals.' I'm always told that 'all of the documentation is on-line.' One of our wonderful Unix workstations refuses to display anything other than black text on a black background when you access Mentor's help file! In contrast, although support for PC-based tools varies from vendor to vendor, they at least have the same kind of hardware and operating systems, so you can work problems out with them."

"I haven't used Linux," he continues, "but I have worked on HP and Sun workstations. Support is nonexistent. Only the local Unix gurus can keep it all running, because our local system is different from systems at other locations. Simple things like typefaces (in the case of Mentor) can send the Unix boxes into a tailspin."

The unnamed engineer with DEC's Engineering Research and Development unit quoted at the beginning stresses the importance of documentation from a different perspective. "One of NT's attractions," he notes, "is that Microsoft products are popular" for producing documentation. "That leaves managers saying, 'Why buy two machines when I can buy one?' I heard a fellow engineer make a very sensible statement: 'Let's come up with standard formats for documents, spreadsheets, and so forth. For example, we could use HTML. That would allow engineers to pick the tools that best suit their needs without having to worry that someone else might not be able to read the documentation.' Applets for just about any office suite component could make it possible to construct basic documents viewable by anyone with a browser."

(In addition, in May Corel Corp. [Ottawa] announced at a meeting of Linux users that it will develop a suite of office applications for Linux. Corel currently offers Corel Wordperfect 7 for Linux, and it will release Wordperfect 8 Personal and Server Editions for Linux this summer.)

Whose economics?
Jonathan Mayer, a chip designer at an unnamed start-up in Irvine, Calif., suspects that what "scares away commercial developers" is the fact that Linux is free. "Several projects are currently under way to develop free EDA tools for Linux--including a Verilog simulator and a synthesis tool. Commercial tool companies are afraid that by supporting the culture of free software, they're putting a bullet through their own heads. NT is a safer proposition. It gives the customer the desired cheap hardware base but keeps barriers to entry into the tools market high.

"Eventually, free EDA tools--and free software in general--will replace the products of the commercial software industry," he believes. "This is something of an extreme viewpoint," he concedes, but the desire to forestall that day, he says, explains why "companies like Synopsys and Cadence stay away from free [Linux OS] software."

Contributor Murry Shohat is a freelance writer based in Santa Rosa, Calif.

To voice an opinion on this or any Integrated System Design article, please email your message to miker@isdmag.com.

integrated system design  August 1998