Petreley's column: LinuxWorld attendees on Windows NT

I'm smack-dab in the middle of the LinuxWorld Expo conference in San Jose, California, as I write this. So far, the conference has exceeded everyone's expectations in terms of participation and attendance. The show floor is often so packed, it is difficult to walk down the aisles.

One of the most interesting things about LinuxWorld is how much of a hybrid show it turned out to be. On one hand, you have the visible presence of IBM, Hewlett-Packard, Compaq, Oracle, Informix and other big names. But on the other hand, there is also an abundance of start-ups and companies that built their reputation supporting Linux, such as Linuxcare (a start-up Linux support organization) and VA Research (a hardware vendor that built its reputation pre-loading and supporting Linux).

The attendees seem to recognise the significance of both. I've overheard a lot of excited hallway chatter about the strong commitment IBM has made to Linux. But when it came time to vote for the show awards, the attendees picked VA Research as the best computer manufacturer. These attendees have not forgotten their roots.

Ironically, I think I have learned more about Windows NT at this show than I have about Linux. Windows NT is on everyone's lips, though what's coming out of their mouths usually isn't flattering. Many Linux newbies at the booths mentioned that they are investigating Linux specifically because of their disenchantment with NT. Others came to learn how to integrate Linux into their NT-dominated enterprise.

Jeremy Allison, one of the lead developers for the Samba Team, addressed the latter group in his talk on how to use Samba to integrate Linux into an NT network. Samba is an open-source product that adds native NT file and print services to Linux (it actually runs on a broad range of Unix flavours, including Solaris and FreeBSD).

The obvious advantage of running Samba instead of NT is that Samba and Unix are virtually crash-proof. And recent benchmarks have demonstrated that Samba can run NT file and print services as much as 250 per cent faster than Windows NT itself.

The most obvious disadvantage of running Samba is that it doesn't quite provide all of the necessary domain controller services. Right now, you really need to use a genuine NT server for your primary domain controller.

The Samba team is addressing this feature gap. They have discovered some interesting security flaws in NT along the way - some of which Allison shared in his tutorial. For example, he illustrated how you can use a packet sniffer to discover a computer's secret session ID, which you can then use with an encrypted password to gain full access to an NT server. The interesting thing about this particular security leak is that you don't even have to decrypt the password for this crack to work.

Allison also described why certain benchmarks don't test Windows NT performance in a realistic manner: NT uses opportunistic locking.

That means that if I want a file on an NT network and nobody else is using it, NT ships the entire file to my computer. As I make changes to the file, the changes take place only at my computer. NT doesn't update the server until I'm done with the file, or until someone else tries to access the file.

So, unless a network benchmark actually forces multiple stations to access the same files during a portion of the test, the benchmark is really testing the performance of the clients, not the server. (Windows NT advocates take note: If your users don't share files on the server, all you have to do in order to make it look like you've increased server performance is to buy your users faster workstations.)But the most interesting tidbit of NT information I heard was a rumour that I picked up off the show floor. Apparently, Windows NT has a habit of limiting its file cache to 300MB of RAM, even if you try to tune it otherwise. So if you have 1GB of RAM on your file and print server, most of that RAM is going to waste. (Linux advocates take note: If you want to demonstrate how much more scalable Linux can be than Windows NT, run your tests on servers with 512MB of RAM and then 1GB of RAM.)The 300MB limitation seems to have stumped both this customer and Microsoft support. If you know of a fix, please let me know, and I'll pass it along.

Former consultant and programmer Nicholas Petreley can be reached at nicholas_petreley@infoworld.com. Visit his forum on InfoWorld Electric at www.infoworld.com.

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