Jon “maddog” Hall | GPL 3 | GCJ | VMware | QEMU | UML | Xen | Wine REVIEWED VMware 5.5 ™ Since 1994: The Original Magazine of the Linux Community MAY 2006 | www.linuxjournal.com Virtual Linux NEW COLUMN: Jon “maddog” Hall’s Beachhead Tales from the Beach Embedded Java with GCJ Using RTNETLINK AN PUBLICATION USA $5.00 PLUS CAN $6.50 U|xaHBEIGy03102ozXv!:; Is Linux VoIP Ready? MAY 2006 CONTENTS Issue 145 FEATURES ON THE COVER: IMAGE BY AYAAZ RATTANSI 60 RUNNING SOUND APPLICATIONS UNDER WINE 72 XEN You can make Linux sound better with a little Wine. Xen’s unusual approach to virtual systems can give it a speed edge. Dave Phillips Irfan Habib 64 USER-MODE LINUX ON THE COVER Run Linux on top of Linux? It makes sense. Really. • VMware 5.5, p. 56 Matthew E. Hoskins • Jon "maddog" Hall's Beachhead, p. 46 68 QEMU: A MULTIHOST, MULTITARGET EMULATOR • Embedded Java with GCJ, p. 76 Can a free virtual system offer what you need? • Using RTNETLINK, p. 86 Daniel Bartholomew • Is Linux VoIP Ready? p. 80 2 | may 2006 www.linuxjournal.com MAY 2006 CONTENTS Issue 145 COLUMNS REVIEW 22 REUVEN LERNER’S 56 VMWARE WORKSTATION 5.5 AT THE FORGE FOR LINUX HOSTS Google Web Services Mick Bauer 28 MARCEL GAGNÈ’S COOKING WITH LINUX The Virtual Streets of $HOME INDEPTH 80 IS LINUX VOICE OVER IP READY? 76 EMBEDDED JAVA WITH GCJ 34 DAVE TAYLOR’S GCJ may not be for end-user applications, WORK THE SHELL but it’s the bomb for embedded systems. Counting Cards Gene Sally Next Month 36 MICK BAUER’S 80 IS LINUX VOICE OVER IP READY? PARANOID PENGUIN What are the viable VoIP options for Linux Security Features in Debian 3.1 and how do they compare? Machtelt Garrels STORAGE 42 DEE-ANN LEBLANC’S Next month, we’re going fishing. Why GET YOUR GAME ON 86 MANIPULATING THE NETWORK not? Did you know that you can use Playing PlayStation Games ENVIRONMENT USING RTNETLINK fish:// for secure access to files over a network? In fact, we’ll tell you about in Linux Socket to me with the RTNETLINK kernel interface. a number of kioslaves that KDE uses to make network storage transparency Asanga Udugama 46 JON “MADDOG” HALL’S a breeze. While you’re at it, you may BEACHHEAD want to dump your reliance on NFS or Tales from the Beach 93 TOP TEN TIPS FOR Windows (Samba) shares in favor of GETTING STARTED WITH PHP SSHFS, a user-mode filesystem that 48 DOC SEARLS’ Want to avoid common pitfalls when works over the secure shell, SSH. getting started with PHP? LINUX FOR SUITS Also, Linux Journal tells you about Marco Fioretti Linus Takes a Pass on the installing Yellow Dog Linux on an New GPL Draft iPod, security features in Red Hat Enterprise 4 and recovering RAID and 96 NICHOLAS PETRELEY’S IN EVERY ISSUE LVM2 volumes. We’ll introduce you to ETC/RANT Gambas, tell you how to set up and 10 LETTERS use Tripwire and how to tap in to The 64-Bit Question 14 UPFRONT Linux kernel hotplug events. 54 NEW PRODUCTS 81 ADVERTISER INDEX 4 | may 2006 www.linuxjournal.com Editor in Chief Nick Petreley, [email protected] Executive Editor Jill Franklin [email protected] Senior Editor Doc Searls [email protected] Web Editor Heather Mead [email protected] Art Director Garrick Antikajian [email protected] Editor Emeritus Don Marti [email protected] Technical Editor Michael Baxter [email protected] Senior Columnist Reuven Lerner [email protected] Chef Français Marcel Gagné [email protected] Security Editor Mick Bauer [email protected] Products Editor James Turner [email protected] Contributing Editors David A. 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PO Box 980985, Houston, TX 77253-3587 USA Editorial Advisory Board Daniel Frye, Director, IBM Linux Technology Center Jon “maddog” Hall, President, Linux International Lawrence Lessig, Professor of Law, Stanford University Ransom Love, Director of Strategic Relationships, Family and Church History Department, Church of Jesus Christ of Latter-day Saints Sam Ockman, CEO, Penguin Computing Bruce Perens Bdale Garbee, Linux CTO, HP Danese Cooper, Open Source Diva, Intel Corporation Subscriptions E-MAIL: [email protected] URL: www.linuxjournal.com PHONE: +1 713-589-3503 FAX: +1 713-589-2677 TOLL-FREE: 1-888-66-LINUX MAIL: PO Box 980985, Houston, TX 77253-3587 USA Please allow 4–6 weeks for processing address changes and orders PRINTED IN USA USPS LINUX JOURNAL (ISSN 1075-3583) is published monthly by SSC Media Corp., 2825 NW Market Street #208, Seattle, WA 98107. Periodicals postage paid at Seattle, Washington and at additional mailing offices. Cover price is $5 US. Subscription rate is $25/year in the United States, $32 in Canada and Mexico, $62 elsewhere. POSTMASTER: Please send address changes to Linux Journal, PO Box 980985, Houston, TX 77253-3587. Subscriptions start with the next issue. LINUX is a registered trademark of Linus Torvalds. letters Kudos on the Redesign Substantiate Your I received my copy of the March 2006 issue of LJ, Dislikes about GNOME and I was surprised to see the graphic design. I think I’m a KDE refugee and much prefer GNOME, so I the new design is awesome. Thanks for your work. was surprised at the depth of [Nicholas Petreley’s] — dislike [see the March 2006 etc/rant column]. It’d be Stefano nice to know what objective standards he’s measur- ing GNOME against. I’m not suggesting that GNOME Thank our artist extraordinaire, Garrick Antikajian, is “the best”—for example, I too dislike Nautilus and for the spectacular new design!—Ed. usually install another file manager. — Separation of Church and Ads Sonia Hamilton I’m not so sure I like the new look for LJ. It’s difficult to tell where the ads end and the articles I will be more specific in a future rant. In the mean- begin. I feel that it acts as a distraction to the time, as far as what a user sees, GNOME is a window reader and hides valuable information among the manager, panels and file manager. The minimalistic noise of advertising. window manager, Metacity, doesn’t have much to do — with GNOME. The panels get more minimalistic with William W. Atkinson each release. The only substantial component of GNOME is Nautilus, and you replace it. What does Blackjack in Fewer Draws that tell you?—Ed. I just read the “Writing a Shell Game” by Dave Taylor in the March 2006 issue of Linux Journal, What a GNOME Needs and the technique he used for shuffling cards I think the lesson to be learned from both open-source seems somewhat inefficient and incorrect. Taylor is and commercial software is that everyone has different randomly selecting cards from a fixed array. A far needs. [GNOME should come up with a method] that better algorithm would be a swap-based shuffle, would allow people to choose just what level of fea- where you walk along the deck, swapping each tures are available to users, what the defaults are and card with a randomly chosen other card. The code so on. As distro makers get a better sense of the vary- to implement this is shorter than Taylor’s “choose ing classes of users, they can continue to fine-tune until bored, then scoop up the rest” method. In their policies without having to be full GUI developers. bash, you could do it with: And as users themselves grow, they can be given the option of moving to a more advanced GUI policy. This # Shuffle the deck would be an elegant way of satisfying everyone’s i=52 needs. And it keeps in line with what I think of as real while [ $i -gt 0 ]; do choice in the traditional UNIX sense. swap_i=$(( ( $RANDOM % $i ) + 1 )) — swap=${deck[$swap_i]} Danny deck[$swap_i]=${deck[$i]} deck[$i]=$swap GNOME Does Not Offer Choice i=$(( $i - 1 )) The only real complaint I have against GNOME is that done it doesn’t support no-auto-raise-on-focus. You Google it, and you find letters that are six or seven years old No need for creating a second deck from a first—this asking when it will be available in GNOME, with the shuffles in-place. Still, I’d like to thank Dave for the GNOME developers pretty much ignoring the request article, because although I know I’ve encountered or saying, “never”. So to the people who say that bash arrays before, somehow I just could never get GNOME offers choice, ask them why you can’t the hang of the syntax. His article spells it out in an choose to have the focus in a window that is partially understandable and useful way. occluded? If you get the Microsoftian response of — “Why would you want that?”, then you have demon- Steve Fink strated that they really don’t care about choice.