Using Perceus/Warewulf as your Cluster Management System (CMS) can speed cluster setup and deployment by automating a number of repetitive tasks.
Monthly Archives: July 2008
Developing for GPUs, Cell, and Multi-core CPUs Using a Unified Programming Model
Posted on July 2, 2008
The need to suddenly start developing parallel software poses a severe challenge to the entire software industry.
More From the Cult of Charles H. Hayward
Posted on July 2, 2008
Good books on hand work are hard to find, and after I recommended Robert
Wearing’s “The Essential Woodworker” in 2007, copies became difficult to find at a
reasonable price. I swear I don’t have a secret stash of these books I like, though
it would be a nifty way to make some cash on the side.
If you cannot get Wearing’s excellent book, I have a great alternative: Charles H.
Hayward’s “Carpentry for Beginners” (Emerson Books). This little jewel slipped under
my radar for many years because of the title. Carpentry? Why would I want a book about
building a coal hutch?
Well as it turns out, we moderns are a bunch of unskilled dufuses (or should that
be that dufi? I forget). What a mid-century Briton considers carpentry is more like
what we would consider fine furniture building. (And what we call carpentry must be
one notch above flint knives and bear skins, I suppose).
“Carpentry for Beginners” is an excellent book for building basic hand skills. Hayward
covers it all, from basic sharpening to flattening a board, mortising, basic dovetailing,
half-laps and even case construction. The book is entirely focused on hand work because
it is assumed that the home carpenter wouldn’t have any machines lurking in the scullery.
What I think is brilliant about the book (and I hope to steal for my own future efforts)
is how Hayward first teaches you the basic strokes: sawing, chiseling, boring, planing,
marking, testing. Then he shows you how to combine these basic skills into dealing
with real-life assemblies. There are entire chapters on “How to Make a Door,” “How
to Make a Box” and “How to Make a Drawer.”
Then these are followed by informative single-page illustrations that walk you through
many of the basic joints.
That’s the first 109 pages; the rest of the book is a walk through your swinging uncle’s
house. Hayward shows you how to build swanky item after swanky item for your pad,
including a television chair and some Danish un-modern tables. You can probably skip
these chapters, except for the section on building a tool chest and workbench trestles.
Where do I find out-of-print books such as this? Try:
Now I’m off to troll these sites to buy up 100 copies of Graham Blackburn’s old books
for next week’s blog entry.
P.S. Click here to
read about other books I’ve recommended.
Screen-by-Screen Guide to Installing KDE Apps in Windows [Screenshots]
Posted on July 2, 2008
A project to port the KDE Linux Desktop’s apps to Windows has been slowly gathering steam for some time now, but installing some of the more noteworthy apps, including the Kopete messenger, Amarok media manager, and Konqueror browser, can be a bit wonky. The Simple Help blog has a helpful screen-by-screen explanation of how to install KDE's backend in Windows and get your favorite apps installed and running. Not every project ports perfectly—Amarok, for example, requires some tweaking to get sound working—but some work just fine. For a fuller virtualization of KDE (or GNOME) apps in Windows, check out Adam's guide to running Linux apps seamlessly in Windows.
How to install and run KDE programs in Windows [Simple Help]
PDF Download 2.0 Beta Adds Advanced Web-to-PDF Conversion [Featured Firefox Extension]
Posted on July 2, 2008
Windows/Mac/Linux (Firefox): The makers of the previously-posted PDF Download extension have released a 2.0 beta that adds some key features, including a full web-to-PDF converter that retains CSS styling, web links, and layout details. The extension has also beefed up its PDF-to-HTML rendering, and works in Firefox 2 & 3, Flock, and other Mozilla-based projects. The developers have made 10,000 beta sign-ups available, with more to come. Hit the link below for more details on what’s new in PDF Download 2.0.
Weblog Tools Collection: Plugin Coders and WordPress 2.6
Posted on July 2, 2008
What Plugin Coders Must Know About WordPress 2.6: Just like it sounds, Ozh has started a post, followed by a lively comment thread, on the challenges that can be faced by plugin coders with WordPress 2.6. This might be a good time (WordPress 2.6 Beta 2 is out) to start digging into your plugins to get them to be 2.6 compatible.
What is the maximum number of commands queued to a LUN
Posted on July 1, 2008
This is not quite a one liner as I’m reusing the code from a previous post to print out the devices in a human readable form other wise it is just a one liner and was when I typed it in.
The question posed here was what is the maximum number of commands sent to a LUN at any one time? Clearly this will max out at the throttle for the device however what was interesting, since the customer had already tuned the throttle down and the problem had gone away was what was their configuration capable of sending to the LUN:
#!/usr/sbin/dtrace -qCs
#define SD_TO_DEVINFO(un) ((struct dev_info *)((un)->un_sd->sd_dev))
#define DEV_NAME(un)
stringof(`devnamesp[SD_TO_DEVINFO(un)->devi_major].dn_name) /* ` */
#define DEV_INST(un) (SD_TO_DEVINFO(un)->devi_instance)
fbt:*sd:*sd_start_cmds:entry {
@[DEV_NAME((struct sd_lun *)arg0),DEV_INST((struct sd_lun *)arg0)] = max((struct sd_lun *)arg0->un_ncmds_in_driver)
}
END
{
printa("%s%d %@dn", @);
}
This produces a nice list of disk devices and the maximum number of commands that have been sent to them at anyone time:
# dtrace -qCs /var/tmp/max_sd.d -n 'tick-5sec { exit(0) }'
sd2 1 sd0 70
#
Combine that with the dscript from the latency bubble posting earlier and you can drill down on where your IO is waiting.
Master Your Digital Media with VLC [Vlc]
Posted on July 1, 2008
Cross-platform media player VLC is often referred to as the “Swiss Army knife of media applications” for good reason: Not only does VLC play nearly any file you throw at it (you even voted it the best desktop media player), but it can do so much more. From ripping DVDs to converting files to iPod-friendly formats, let’s take a look at the four coolest things you can do with VLC and start you on your way to becoming a VLC ninja. Photo by R’eyes.
NOTE: Many of these VLC tricks use the same dialogs, so rather than repeat the same steps every time, I’ll be doing a thorough step-by-step once and then highlighting only the differences in the subsequent mini-guides. I’m using Windows in most of my examples, but since VLC is cross-platform, most of the same tricks should work just as well on any platform. VLC has a Streaming and Transcoding Wizard that’s supposed to make this process even easier, but it’s been buggy for me in all my tests, so I decided to go with the slightly more difficult method detailed below.
Rip Any DVD
You may have thought that you needed some fancy DVD ripping tools to rip DVDs to your hard drive, but VLC can actually rip any DVD with ease. As reader joelena pointed out, since VLC plays the DVD in order to encode it, it can bypass any copy protection. Here’s how it works:
- Open the Disc and Find the Correct Title: Insert your DVD and open it with File -> Open Disc. We need to find the right title to rip from the DVD, so at this point we're going to preview titles from the disc one by one. To do this, start with 0 as your title number and increment one number at a time until you find the title you want to rip. I've found it's quicker if you choose DVD rather than DVD (menus) at the top of the Open dialog so you only have to wade through actual video.
- Pick a Folder to Save the Rip and Name It: Now that you’ve find the right track, you just need to tell VLC that you want to save it. To do so, tick the Stream/Save checkbox, then click Settings. Here you need to tell VLC where to save the file, so tick the File checkbox and pick a folder to save it to and then give it a name (e.g., My DVD Rip.mpg).
Determine Video and Audio Settings: Now you’re ready to tweak the final settings before it’s time to rip. Tick the Video codec and Audio codec, then choose the output codecs you prefer. This is really up to you, and if you don’t have a preference I’ve had good results using the defaults described in this excellent VLC rip guide: mp1v for the video codec and mp3 for audio. If you need a specific file format for a mobile device, you may want to choose a difference encapsulation method and codec. Hit OK when you’re done.- Rip Away: You’ve made it. Just hit OK again (make sure Stream/Save is checked) and it should start ripping.
VLC will rip the DVD faster than real-time playback, and when it’s done (you can follow the ripping process in the corner of the VLC window.
Convert Any Video for Your iPod or iPhone with a Drag and Drop Batch Script
If you regularly convert files to a specific file format—say, for your iPod—you can set up a batch file with VLC that will make video conversions as easy as dragging and dropping the to-be-converted file onto the script.
Create a new text file and save it as VLC Converter.bat. Make sure your filesystem is showing file extensions so you aren’t saving it as a text file (you don’t want to end up with something like VLC Converter.bat.txt). You need to make sure it’s saving with the BAT extension.
If you were building the script from scratch, at this point you’d open up the file you just created and paste “C:Program FilesVideoLANVLCvlc.exe” %1 in the first line. Now you need to get the command line options that describe how VLC should convert the file. For that, you can use the text generated by the Target textbox at the top of the Stream/Save Settings window described in steps two and three of the DVD ripping guide above, which displays the command line options you need for your batch file. Luckily a user at the iPod forums at iLounge already put together a VLC batch conversion script for iPods, so we can just use those settings, which look like this:
“C:Program FilesVideoLANVLCvlc.exe” %1 :sout=#transcode{vcodec=mp4v,vb=1024,scale=1,height=240,width=320,acodec=mp4a,ab=128,channels=2}:duplicate{dst=std{access=file,mux=mp4,dst=%1.mp4}}
That’s a lot of text, but it’s just telling VLC everything you would normally tell it in the Settings dialog. The %1 variable will be replaced by the name of the file you drop on the script. Copy and paste all of that text (and only that text) into your batch file and save it. That’s all there is to it. Next time you have a video file you want to convert for your iPod, just drag and drop it on your newly created batch script. The script was built specifically for converting videos to an iPod-compatible format, but you can build your own scripts to do virtually common conversions you want.
Stream Media to Other Computers
Now that you’re using VLC to rip your DVDs, you’ve got gigabyte after gigabyte of your videos on your desktop. Rather than copying all of those files to any other computer you’d like to play them on, VLC allows you to stream video over your network or even over the internet.
First, go to File -> Open File. Browse to the file you'd like to stream, and then—like above—tick the Stream/Save checkbox and click Settings. This time, rather than outputting the stream as a file, we're going to tick the UDP box and enter the local IP address of the computer you'd like to stream to. On Windows, you can find your computer’s local IP address by opening the command prompt (Win-R, type cmd, and hit Enter), and then type ipconfig and hit Enter.
Once you’ve got that, enter it in the computer you’re streaming from in the text box next to the UDP checkbox you just enabled. Hit OK to accept your settings, then OK again to finish the setup. While you're still on the streaming computer, go to Settings -> Add Interface -> Web Interface.
Now it's time to start the stream on your other computer, and doing so is a breeze. Just open VLC on your second computer, go to File -> Open Network Stream, and—assuming the UDP choice is selected and the port matches the port you used in the setup above (unless you changed it, they should both default to 1234), just hit OK to start the stream.
You’re presented with a slight problem streaming the video using VLC this way, namely that you can’t control the playback from the remote VLC interface. Luckily you already enabled the web interface, so on the computer you’re streaming to, open a web browser and point it to the VLC web interface. If you’re streaming over a local network, find your streaming computer’s IP address the same way you did with the remote computer’s address above, then enter it into your browser with port 8080 appended to the end. Mine looks like 192.168.1.2:8080. Through the web interface on the remote computer, you can control all of VLC’s playback. Handy, huh?
You can stream video over the internet and not just over your local network, but you’ll need to either have a static external IP address or assign a domain name to your computer to do so easily. For more details on streaming with VLC, check out Engadget’s previous guide.
Play Ripped DVDs
If you prefer keeping ripped DVDs entirely in tact with you rip them to your computer, VLC may not be your tool of choice for ripping. Instead I’d recommend an alternate ripping tool like our one-click DVD ripping solution DVD Rip or one of the other DVD ripping methods we’ve covered in the past. Once you’ve ripped the full DVD to your hard, VLC comes in handy once again to play that ripped DVD, menus and all.
We’ve highlighted how to play full ripped DVDs with VLC before, but for an even easier solution, check out DVD Play, a Lifehacker Code original that works as a more attractive front end to playing back full DVD rips with VLC.
We’ve really only scratched the surface of all the awesome things you can do with VLC, so if you’ve got a favorite VLC technique of your own (or even favorite encoding settings), let’s hear about it in the comments.
Adam Pash is a senior editor for Lifehacker who practices his VLC kung-fu regularly. His special feature Hack Attack appears every Tuesday on Lifehacker. Subscribe to the Hack Attack RSS feed to get new installments in your newsreader.
Mozilla Weave Synchronizes Your Browsing Experience [Screenshot Tour]
Posted on July 1, 2008
The newest version of Mozilla’s experimental browser-syncing tool, Weave, just hit the net, and it’s seen a few marked improvements since it was first available. Going beyond bookmarks, Weave can match up your Firefox 3 settings, cookies, browsing history, and even tabs between browsers, with experimental support for passwords and form data—in other words, just about everything except extensions, themes, and plug-ins. There's a lot more to come, and it's still a pretty rough around the edges—this is, after all, just version 0.2—but follow along after the jump to see some of what Weave can do, or at least one day will do, to keep your Firefox browsing consistent and convenient.
The first step is heading to Weave’s home page and installing the add-on. Firefox in Windows detected a security certificate problem and made me confirm Mozilla’s worthiness three or four times before I could get in. After installing the add-on and restarting Firefox, you’re prompted with a welcome screen (with a requisite warning about Weave’s experimental nature), and then your first choice:
If you’re setting up the first of your Firefox browsers that you’ll grab and sync settings from, choose the left button. If you’re trying to pull your settings from Mozilla’s cloud for another browser or system, choose the right. If you’re signing up new, you’ll be asked for a username, email address, password, and then a separate “passphrase” that unlocks the encryption on your server-stored data.
Next, you’ll be asked what you want to back up and sync on the computer you’re installing Weave on:
You'll see again that passwords and form data are "experimental" features. I tried to enable both, and while syncing to a new Firefox profile in Vista, Weave failed with a "failed to acquire lock" error—your mileage may vary, of course, but I found success by choosing the non-experimental defaults.
I'll note here that your initial sync is going to take a loooooooooong time—about 6 minutes for an XP machine to pick up the data from a previous sync, and my Vista system went for 10 minutes before I'd decided to move on—though it apparently worked, given that XP grabbed my bookmarks, cookies, and "awesome bar" shortcuts. If everything did go well, you'll see the screen at right, and you can resume your normal browsing.
To keep your browser synced up, Weave puts an icon in your status bar that lets you sign in or out, sync on command, and see your last sync and activity log. You'll also see a little spinning sync wheel in a pop-up window when you close down the browser—which can stick around for a minute or more, depending on the connection and what changes you've made. You'll also get a Weave menu added to your Firefox preferences, with some troubleshooting logs and syncing options, most of which you can access from the status bar.
I tried out Weave on two different profiles each in Windows Vista, Windows XP, and Linux. If you’re willing to try out Weave, here’s a few problems I encountered that you might also find:
- Linux = no go: At least on my system. Weave just refuses to accept my encryption passphrase, and it looks like it’s a disconnect between a locally-stored file and Mozilla’s servers. Let us know in the comments if you find a fix or work-around.
- Re-installation prompts: On my XP installation, Weave seemed to continually ask me to install an add-on called “Latest Weave” upon starting up Firefox. I agreed three times, until I realized it was misinformed.
Occasional syncing hang-ups: Even on systems where Weave managed to successfully install, sync attempts at start-up or shutdown would lag or sometimes outright fail.- Where’s the bookmark trading?: Weave was said to let users trade read-only bookmarks with other registered users, but I didn’t see any send or receive options in any dialogs or settings. Can you find the gateway?
Caveats aside, Weave is looking pretty exciting right now, and if it works fine on your system, it could be a major time-saver and mobility helper.
What’s your impressions of Weave? Got any tips or fixes for your tester or fellow commenters? Let’s hear about it in the comments.
Weave [Mozilla Labs via Google Operating System]