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OSdata.com: reliability 



    Reliability is generally considered important by end users. Not all companies making operating systems have a similar standard. Even among operating systems where reliability is a priority, there is a range of quality. Also, an operating system may be extremely reliable at one kind of task and extremely unreliable at another.

    Microsoft has been running a series of television commercials claiming that Windows 2000 is reliable and that it can be left unattended for days at a time without human intervention. Windows 2000 is in fact still less reliable and stable than the least reliable version of UNIX (even the free ones), and will require a full time maintenance and administration staff, as well as at least a part time staff or independent consultants for recurring repair work.


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Reliability and Scalability Graph

—D.H. Brown.w51

downtime costs

    “Downtime Costs The cost of downtime, in qualitative measures such as customer service or quantitative measures such as missed orders, is becoming a crucial issue to even the smallest companies as they move into the world of E-business. Users can add servers as applications grow and transactions become critical, but that doesn’t address availability and systems-management issues, says Dick Sullivan, [VP of NT solutions for IBM’s server business unit]. ‘Even the small organization can’t tolerate a 97% availability rate for E-business,’ he adds.” —“The Hidden Cost Of NT”w70

     Windows NT is less stable an operating environment than UNIX. While Microsoft might argue this point — that UNIX is less prone to system crashes, and thus requires less in day-to-day maintenance than NT — users of both systems generally agree.
     For instance, Wayne Fiori, manager of technical services at INACT Health Management Systems, in Mountain View, CA, says INACT has both UNIX and Windows NT servers but runs its mission-critical business application, a program that monitors diabetic and asthmatic patients remotely, on the former. “The best way to put it,” he says, “is the longest uptime [for NT] is three weeks, but with our UNIX boxes, it’s 442 days.
     “If I need to make a change on UNIX, I don’t have to reboot, but do so on NT,” he adds. “We’re a 24 x 365 business — we have to be up all the time, and NT is not capable of providing this level of uptime yet.”
     Instead, he uses Windows NT as a file and print server on the 50-employee company’s LAN. In this situation, “Nobody cares if we have to reboot once a week,” he says. — Jim Carr; MicroTimesm1

    “Are you sure that’s an NT server you’re connecting to at work? IS employees in many corporations have secretly installed Unix servers that provide native NT services. Why take such a risk? Linux and FreeBSD are free, as is SAMBA, the software that provides NT services. So the IS department saves money. And managers are unlikely to find out Unix is behind the scenes because fewer people will complain about server downtime.

    “Fewer people will complain because the servers are more stable than Windows NT. Linux, FreeBSD, and BSDI Unix outperform Windows NT by a wide margin on limited hardware, and under some circumstances can perform as well or better than NT on the best hardware. Once behind in scalability features, Unix on Intel is catching up and may soon surpass NT in the number of processors it can use, and how it uses them.” —Nicholas Petreley, “The new Unix alters NT’s orbit”, NC Worldw74

    Windows NT Server is now part of the corporate infrastructure. But according to some IT veterans, NT Server doesn’t belong there yet. NT lacks the robustness, reliability, and scalability found in more-mature Unix, AS/400, and host systems, they say.” —“The Hidden Cost Of NT”w68

     “We’re finding (Solaris) getting into smaller and smaller businesses,” says Tom Gouge, senior product line manager for Sun’s Solaris servers, and a PC-based version is a natural addition to the company’s product line. “I think it’s because more of them are depending on these systems to be mission-critical, whether it’s for running their Web sites or e-mail services, or EPR, or they have a branch office that absolutely must ‘talk’ to the headquarters. We see more and more demand for (constant) uptime.” —Jim Carr, MicroTimes; Oct 30, 1998m1

    John Kirch: “UNIX is a mature, technically superior group of operating systems with a proven track record for performance, reliability, and security in a server environment. The almost thirty years of continual development, performed often by volunteers who believe in what they’re doing, has produced a group of operating systems—and extremely powerful multiprocessor server hardware tailor-made to its needs, whose performance is still unparalleled by Intel hardware—that not only meets the demands of today’s computing needs, but in many cases exceeds them.
     “Why Windows NT Server 4.0 continues to exist in the enterprise would be a topic appropriate for an investigative report in the field of psychology or marketing, not an article on information technology. Technically, Windows NT Server 4.0 is no match for any UNIX operating system, not even the non-commercial BSDs or Linux.”—John Kirschw22

     “For example, are you sure that’s an NT server you’re connecting to at work? IS employees in many corporations have secretly installed UNIX servers that provide native NT services. Why take such a risk? Linux and FreeBSD are free, as is SAMBA, the software that provides NT services. So the IS department saves money. And managers are unlikely to find out UNIX is behind the scenes because fewer people will complain about server downtime.

    “Fewer people will complain because the servers are more stable than Windows NT. Linux, FreeBSD, and BSDi UNIX outperform Windows NT by a wide margin on limited hardware, and under some circumstances can perform as well or better than NT on the best hardware. Once behind in scalability features, UNIX on Intel is catching up and may soon surpass NT in the number of processors it can use, and how it uses them.

—Nicholas Petreley (editor-in-chief of NC World and columnist for InfoWorld and NT World Japan), “The new UNIX alters NT’s orbit: The re-emergence of UNIX threatens to modify the future direction of NT”, NC World, April 1998w22

    OpenBSD’s primary focus is on correctness and security.” —“Microsoft Windows NT Server 4.0 versus UNIX”w51

    Linux is a rock-solid system that supports a wide range of hardware and outperforms most other systems ” —Internet Week (Formerly Communications Week) Sept 1, 1997w26

     “It’s powerful, it’s open, it’s free. That’s why this Unix is entering Corporate IS. Cost is one of the last things people mention when talking about Linux’s benefits. Reliability is one of the first.” —Byte Magazinew26

     “Tim Payne, director of database marketing at Oracle, says many of his company’s corporate customers have made large investments in Linux. When Oracle announced in July [1998] that it would be offering 24x7 support for Oracle8 on Linux, he says 300 customers called the next day asking about availability. ‘It’s reliable, it’s proven, it runs on commodity Intel boxes, and it’s a really low-cost alternative to NT,’ says Payne. ‘The fact that you are going to be able to get enterprise quality support from Oracle to deploy on the Linux platform will help customers adopt Linux.’ ” —Ann Harrison, “In LINUX We…”, Software Magazine, Cover Story, September 1998w51

    Windows NT systems carry lower sticker prices than their Unix Unix counterparts, but ongoing maintenance and support requirements can make them much more costly to run.” —“The Hidden Cost Of NT”w68

     Microsoft is notorious for unreliable software, both in operating systems and application programs. In the Windows world (following the example set by Microsoft), it is the custom to ship untested software as quickly as possible and let paying customers be the “beta testers”. This dramatically cuts engineeering costs. Also, it is common in the Windows world (again following Microsoft’s leadership) to ignore fixing bugs unless a “critical mass” of complaints arise. If a small number of users are having a problem, no matter how catastrophic, Microsoft and many other Windows software developers will simply ignore the problem and claim that their software license absolves them of all responsibility for fixing any bugs (and you wonder why Ralph Nader strongly criticizes Microsoft as anti-consumer).

     Bill Gates, when questioned about the more than 10,000 bugs Microsoft acknowledged existed in Windows 98, claimed “There are no significant bugs in our released software that any significant number of users want fixed.…The reason we come up with new versions is not to fix bugs.…It’s the stupidest reason to buy a new version I ever heard.”

    At the 1998 COMDEX, Bill Gates compared the computer industry with the auto industry, stating, “If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1,000 miles per gallon.”

    GM’s CEO responded by asking, “Yes, but would you want your car to crash twice a day?”

     “Any systems/network administrator knows from experience that there are two important issues to be considered when setting up a file server or adding a new network user: security, i.e. passwords and file permissions; and quotas for limiting disk usage of any new or existing users or groups. ƒ More important than this issue, however, is that NT does not provide any mechanism for limiting a user’s disk usage! ƒ If your NT server should function as a file server — what else can you do with it really? — don’t plan on being able to prevent users from crashing the server by filling up the disk(s) with their data.”—John Kirschw22

     “Digital OpenVMS Systems Continuous Computing … 24 * 365. When configured in a fault tolerant cluster, up-time and availability is typically measured in years. A system crash or the equivalent of a “kernel panic” is considered a rare occurrence. OpenVMS will detect and give early warnings of most hardware failures. OpenVMS can diagnose both program and operating system problems while the system is running, and will provide an accurate report of why a program failed. You will find few operating systems comparing themselves to OpenVMS in terms of reliability.” —John Malmberge85


    “On the whole, the MacOS X beta was surprisingly stable, along with the expected quirks and minor problems.” —“X a perfect X”, Open (a Linux e-business magazine)m4

     “Oriental Trading Co., a $200 million direct marketer, plans to move its Internet server off NT Server after suffering excessive downtime and high maintenance demands. ‘Once a week it goes down—anywhere from 15 minutes to several hours before we figure out what’s wrong,’ says Bob Cargill, Oriental’s systems manager. ‘That’s not what we want in a Web server. When customers aren’t able to get through and place their orders, that’s a ticket to low customer satisfaction.’
    “While there are ways around these reliability and support problems, customers such as Oriental Trading feel safer with an alternate platform. Cargill and his team are implementing IBM’s AS/400 multiprocessing RISC server. NT Server is used only to let customers view its catalog over the Web—not for order processing. Oriental doesn’t plan to upgrade to the next NT version.” —“The Hidden Cost Of NT”w68

     “Net-Temps Inc., a two-year-old online recruitment firm, works with 1,000 staffing firms looking for IT talent. Last year, it needed to upgrade its server. Since the company wasn’t saddled with legacy systems, NT seemed like the best option. ‘We looked for a better, bigger box,’ says Kevin Strange, Net-Temps’ technology VP. ‘I couldn’t justify a $30,000 Solaris server when a Dell NT server was $5,000. That’s where I made my mistake.’ ” —“The Hidden Cost Of NT”w68

    “Net-Temps experienced three months of downtime on its NT Server before giving up on theplatform. ‘We have 40,000 people a day accessing our site, and NT was down weekly,’ says Strange. ‘If a video card went out, we lost the system. A cable would go out, and the server would crash.’ Net-Temps estimates it lost $15,000 every hour that job seekers couldn’t get through. ‘I can’t even compute the costs when my customers—recruitment firms—can’t get through,’ he says. While Strange continues to evaluate NT for system enhancements, he says today’s NT isn't any closer to the functionality of Sun’s Solaris, which Net-Temps moved to.” —“The Hidden Cost Of NT”w69

    “As Windows users are being plagued by computer viruses, spam, buggy software, and Web pop-up ads, some are questioning why the Redmond, Wash.-based software behemoth has failed to integrate security and repair features that could make computers less prone to problems.
    “ ‘Microsoft has added lots of bells and whistles to Windows to protect their operating system franchise over the years, but when it comes to Windows security and reliability, they’ve done comparitively little until recently,’ said Alan Paller, director of research at the SANS Institute, a Bethesda, Md.-based computer security and training organization.
    “ ‘It’s like they are selling faster cars with more powerful engines but leaving off the seat belts and air bags — all those critical things that make customers safe when using their products,’ he added.
    “Microsoft’s critics say the reason the company isn’t eager to add security features is simple: Doing so wouldn’t help it fend off competitors whose products could undermine the spread of Windows.
    “ ‘You would think there would be money to be made in Microsoft having some kind of more effective antiviral program of their own,’ said Andrew Gavil, an antitrust expert and law professor at Howard University. ‘But virus programs don’t present any threat to their operating system monopoly.’ ” —Los Angeles Times, “Microsoft Runs Into Bundling Dilemma”, March 27, 2004n4

Blue Screen of Death

     According to ZDNet’s Ed Bott, “You reboot less often [than with Windows 95], but NT has a long way to go before it consistently achieves the uptime that Unix users take for granted. A buggy driver or a memory conflict in NT’s internals typically results in STOP errors, also known as the Blue Screen of Death, a fatal listing of hexadecimal memory addresses and module names in bright white letters on a blue background. Even more insidious are memory leaks, which slowly drain resources from the operating system until performance becomes so sluggish that rebooting is the only alternative. Unfortunately, the Blue Screen of Death isn’t rare. Microsoft has created a special Web-based troubleshooter to help you decode the top 15 STOP error messages. Most depressing of all, these crashes are so common that they’ve earned the ultimate in backhanded compliments—their own widely used acronym, BSOD.”w64

    Windows NT suffers from design flaws as annoying as its inexcusable handling of system DLLs to a dangerous kernel model that invites driver crashes.” —Nicholas Petreley, “The new Unix alters NT’s orbit”w74

Windows Registry

     Windows NT uses a central registry data base for keeping track of key configuration information on the operating system and all the application programs. According to computer engineer Bob Canup (chief design engineer at two different computer manufacturers, including the design that briefly held the record for fastest microcomputer), the existence of the registry is a fundamental design flaw that compromises reliability:

    “I think that you will agree with me that Microsoft knows much more about computers than just about anyone that you know: they are the largest software firm in the world.
    When Microsoft created MSN they of course used NT; here was a public display of their software and they could hardly afford to fall flat on their faces by using anything else. Besides, they could get NT for free — rather than spending millions of dollars on Unix licenses. At least they tried hard for several weeks to use NT before they were forced to abandon the project as hopeless; MSN is now run on Unix.
    Stop to think for a moment: if you were Bill Gates, would there be any way you would let that happen? Microsoft has billions of dollars to spend, and thousands of programmers who literally have NOTHING better to do than fix whatever is wrong with NT. After all Microsoft has stated that they are betting the entire future of the company on NT. Yet they went to Unix, and have made no attempt to go back to NT. WHY? The only possible answer is that Microsoft discovered that NT has a fatal design flaw, at its very core, which they are powerless to fix.
    The feature for which Microsoft has received the greatest critical praise in the computer press is the registry: a built in centralized database of settings for the operating system and application programs. There is no question that this is a much cleaner appearing approach than the hodge-podge of initialization files in a Unix /etc directory. In general a database is a much better way of accessing information than unrelated ASCII text files would be. However, as Microsoft discovered, there is one place where a centralized database is not the correct way to do things: at the heart of an operating system.
    A Unix system consults the files in the /etc directory only when a service or program requests the information they contain. NT however must scan the registry before launching any program or service — lest the registry have some settings which are critical to the operation of the program or service. As a result Unix spends very little time doing anything having to do with the /etc directory. NT on the other hand spends more and more time searching and updating the registry as the system ages and grows.
    If you wish to see how dramatic the impact on performance the existence of the registry is install a fresh copy of NT on a system and then add Computer Associates’ Unicenter TNG Framework. Even if you never run the TNG framework every other program on the system will be slowed down because of the data added to the registry. This is not because there is anything wrong with Unicenter TNG, it is because it, quite properly, uses the registry exactly as the Microsoft specifications require. I know of no other operating system where simply adding a program to the system slows down the operation of every other program on the system, even if the added program is never run.
    An NT system starts off its fastest the day it is installed and slows down the more it is used. Adding Visual Basic 6.0 professional to my NT system (a process which expanded the registry by 5 megabytes) caused my 266 MHZ K6-II to start performing about like a 386-20.
    If performance were the only thing which the existence of the registry impacted, that would be bad enough, but there is another much more serious problem caused by the existence of the registry. In a Unix system if you happen to corrupt one of the files in the /etc directory you might lose the service to which the file refers. In an NT system if you corrupt the registry, you lose the entire operating system.
    Much of the real world stability of a Unix system comes from the fact that you are unlikely to corrupt anything in the /etc directory: the files are rarely changed, and being ASCII text files they are easily fixed. In NT on the other hand, not only is the registry soon the largest file in the operating system, it is also the one which is changed the most often. The result is that the registry is the most likely file to be corrupted in an NT system. In addition, a keyed database, such as the registry, is inherently more fragile than ASCII text files. The end result is that in real world, day to day, use NT is much slower and more fragile than a Unix system.
    In essence NT is like a heavy weight boxer with a glass jaw; he looks great in sparring and on paper, but when he gets in the ring with another heavy weight he quickly gets knocked out. NT can never be a contender. The existence of the registry is the fatal design flaw which Microsoft uncovered when they attempted to use NT as a mission critical operating system. They are powerless to fix the problem because were the registry to be removed or changed it would break all of the programs written to Microsoft’s own specifications.
    Simple surface examinations of the OS such as might be conducted at a magazine will never expose those kinds of flaws, and NT looks like a great choice after a surface examination. However, like a beautiful but heartless woman who is only after your money, NT is not something to which you want to be married.” —Bob Canupe87

    “Perhaps I ought to explain what I mean by a ‘fatal design flaw’: a fatal design flaw is one which regardless of its implementation will cause something to fail. Example: A program, whose logic causes it to erase its output file after creating it, and then at a later time attempts to read from the erased file has a ‘fatal design flaw’.
     “I see the existence of the registry as a ‘fatal design flaw’ in NT for the following reasons: 1.) it is the most modified file in an NT system. 2.) the most modified file is the one most likely to be corrupted. 3.) when corrupted the registry crashes the OS.
    “No amount of changing data structures or algorithms can fix those fundamental problems.” —Bob Canupe88

Windows DLLs

    Dynamic Link Libraries (DLL) were first introduced on 1960s mainframe operating systems and provide a method for programs to share commonly used routines. Prior to the introduction of DLLs, shared routines had to be statically linked to a program when it was compiled. If there was a change made to any routine in the library, every program that used the routine had to be recompiled. With DLL, the routines are kept in a special library that is dynamically linked to programs when they are brought into memory to run. Any routine in the DLL can be changed and programs using it will continue to work properly as long as the public interface to the routine remains the same.

    Windows NT is less stable than Unix because it is more vulnerable to clashing shared libraries (DLL conflicts). But it is only left vulnerable in this way because Microsoft likes to overwrite existing system DLLs with its applications (thus secretly “upgrading” the operating system in ways no competitor would dare to do) to gain unfair leverage against its competition. “Fixing” the DLL problem is technical simplicity. It simply isn’t desirable from Microsoft's perspective.” —Nicholas Petreley, “The new Unix alters NT’s orbit”w74

device drivers

    Windows NT has a dangerous driver model because it is willing to sacrifice stability for speed in an attempt to win benchmarks against competing operating systems.” —Nicholas Petreley, “The new Unix alters NT’s orbit”w74

manufacturer comments

     OS/2 Warp: “The stability and compatibility needed to run your business.”w27

     OS/2 Warp Server: “With OS/2 Warp Server, you gain … a highly reliable network operating system.”w35

geek humor

    “This came directly from a computer and should not be doubted or disbelieved.” —Mark J Balbes

    A computer program will always do what you tell it to do, but rarely what you want it to do.

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    Last Updated: March 27, 2004

    Created: June 15, 1998

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