Great discussion by John Resig – Sub-Pixel Problems in CSS: when you mix percentages or ems with pixels, is half-a-pixel a pix or a xel? It’s an unsolvable problem…
Archive | Web Development
Technologies, techniques and neat stuff on the www
MonadLUG notes, 13-March-2008, Philip Sbrogna on WINE
Twelve people attended the March meeting of the Monadnock Region Linux User Group, MonadLUG, held as usual on the second Thursday of the month at the SAU 1 offices on Hancock Road in Peterborough.
Charlie called the meeting to order at 7 PM and we had the usual round of announcements. One member offered an HP LaserJet 4L and a new cartridge to anyone interested. There’s problems with the paper feeding, likely the rollers, and he didn’t have the inclination to fix it himself and went out and bought a new duplexing laser. If anyone’s interested, we can try to get you in touch with him.
Philip Sbrogna was the main presenter, speaking on Wine. Philip works as sysadmin for a local company, and has past experience as a game software developer (as well as a nuclear power
operator, a past profession we share) and is very interested in getting games working well under Linux. Wine Is Not an Emulator, but a API layer that provides the resources Windows executables need to run under Linux. The main page is at http://www.winehq.org and there’s a lot of information available there. Philip was running OpenSuse 10.x and demonstrated how easy it was to use the built-in YAST tool to locate, download and install a current and stable Wine release, version 0.9.42. Despite having practiced it several times, things don’t work the same during a presentation, and Philip was great about rolling with the punches and showing us how to configure, troubleshoot and tweak on Wine. We talked about the commercial alternatives, CrossOver Office from CodeWeavers and Cedega’s work with getting high-end games working, the Application Database at WineHQ where you can examine the list of programs known to work or known to have limitations and pick up suggestions on how to tune the application to your needs.
Ken got a chance to show off the new facilities of the meeting room. A new hi-tech podium’s in place that supports two projector screens, one of which is a touch-screen, dry-erase screen. The project supports computer video, TV tuner, DVD, videotape and a color video camera that can scan and preserve on memory cards,a 21st century opaque projector. Beautiful equipment! It may take us a while to learn the magic X configuration to get it working, so be prepared for a little struggling at the beginning of the meetings.
Next month, Guy Pardoe will demonstrate Joomla 1.5, the newly-released (and significantly re-engineered) content management system written in PHP. There’s a book on Joomla 1.5, written by Barrie North, who’s spoken at the Dartmouth – Lake Sunapee Linux User Group. It’s published by Prentice Hall PTR, an imprint of Pearson Education. Attendees to the recent CentraLUG meeting may recall we had a copy raffled away.
Thanks to Philip for a great presentation, to Ken for providing the space and facilities, to Charlie Farinella for organizing, promoting and moderating the evening, and to all for attending and participating!
State of the Computer Book Market, Part 4 – The Languages – OReilly Radar
By Ted Roche on March 17, 2008 in CSS, FoxPro, JavaScript, LAMP, Microsoft, Perl, PHP, PostgreSQL, Python, Ruby, Technology, Web Development
Over at O’Reilly, Mike Hendrickson posts State of the Computer Book Market, Part 4 – The Languages – OReilly Radar. Bear in mind in the world of lies, damned lies and statistics, these are statistics. Like measurements of job posting vs. languages, or web pages vs. languages, these aren’t an indication of what languages are in use out there, or what languages are suitable for use. This is just a measurement of what book titles sold the most, grouped roughly by language. If the best book on your favorite language is years old, it’s probably shown as small here. If a bunch of crappy books got published on the language-of-the-week, and the authors and publishers did a good job of getting a buzz going, it’s probably scoring high. Don’t use this to decide whether to use vi or emacs, tabs or spaces.
But it’s interesting data.
Notes from DLSLUG, 6-Dec-2007
Fourteen people made it to the December meeting of the Dartmouth – Lake Sunapee Linux User Group, held as usual on the first Thursday of the month and in what appears to be our new place, Haldeman 041, in the lower level of the building next to our previous meeting place.
“Nifties” was the theme, for any presentation that might elicit the reaction “Nifty!” from the audience, and they all did.
Roger Trussell presented a firefox extension using Javascript, XML (“XUL”) and SVG (Structured Vector Graphics, yet again more XML, but rendered by Mozilla as graphics) to create graphically complex interactive structures in Mozilla browser. Nifty!
Glen Page, newly appointed leader of the New Hampshire Society for Technology in Education talked about the happenings at the Christa McAuliffe Technology Conference (which also included presentations by well-known GNHLUG activists Ed Lawson, Bill Sconce and Matt Oquist)
Doug McIlroy showed us some tricks with qsort: qsort is an interface under which each developer could implement their own sorting algorithm, a common homework assignment. Doug argued that a properly designed data set could disappoint anyone who thought they’d created the cleverest quicksort EVER by always returned quadratic (slow) results. You can read the code here. Nifty!
Nick Sinnot-Armstrong: One Laptop Per Child XO-1 laptop: show and tell. A local developer experimenting on a pre-production model of the OLPC with the very capable microphone input (accepts both analog and digital for standard audio as well as measurement data). Nick gave us a tour of the laptop, passed it around for people to get a sense of the size and capabilities. Note that the OLPC charitable project “Get One, Give One” is going on through December 31st. Nifty!
Mike Diehn showed off some very powerful tips and tricks in bash and vi, and pointed to some handy resources at http://pixelbeat.org/ – Nifty!
Bill McGonigle demonstrated Munin, a monitoring and recording tool that’s a great add-on for a facility that’s trying to pick up on problems occuring over time, Built on top of RRDTool, it can record and remember a set of measurements over time. Bill showed how one of his web sites was experiencing a surge that was hurting performance and setting off alarms. By picking a set of parameters to monitor, Bill was able to work out that… well, you should have been there. Nifty stuff!
Bill has an interesting pointer to a project called FON. I’ve been reading through the web site on the FON system. Here’s how I read it: Home/businesses with the proper rights granted by their upstream suppliers can post this access point on their network. Internally, the host can use a private wireless access, encrypted with WPA2 or less. Externally, the WAP advertises itself as FON_AP, an open (no key) wireless access point. Other ‘Fonistas’ – registered members who are actively operating their own FON WAPS – can access the wireless for free. But the great unwashed masses do not get to access it for free. They get to pay for access. A FON pass will apparently let them use any FON WAP for a day. They can purchase it on the spot, or buy a bunch of passes and use them as needed. Not sure of rates or the fine print. The host seems to be able to set it up as a “Linus” and collect no fees themselves or as a “Bill” and share in the dividends that FON makes from paying access. It’s an intriguing business model.
Apparently, on Thanksgiving FON offered their WAP for free for a limited time, and Bill was able to get one, which he raffled off at the meeting.
And last, but certainly not least, Bill McGonigle demonstrated a pair of carol-playing, wireless, dueling-banjo penguins. Nifty!
Thanks to Bill McGonigle for organizing the meeting, to Dartmouth College for generously donating the use of the facilities, and to all who attended and demonstrated Nifties!
Notes from PySIG, 29-Nov-2007: Django in the real world
Fourteen people managed to find their way to the Amoskeag Business Incubator (it’s on SOUTH Commercial Street, contrary to the directions on the ABI site) for the November meeting, one week later than the usual fourth Thursday of the month, of the Python Special Interest Group.
A number of new attendees arrived this month. We pointed out that the mailing list for the group can be found on the DLSLUG and GNHLUG sites, look for “mailing list” and that there was an announcement as well as a discuss list for the group. We pointed out the main calendar at GNHLUG.org as well and talked about other resources.
Several members were new to the area or had come up from Cambridge, MA (our fair city) for the SIG meeting. They pointed out the Cambridge Python Group, who usually posts meeting announcements on Meetup.com, which boasts 103 members on their list! We discussed the ideas for mutual cooperation, and will be glad to cross-post their announcements to the PySIG -announce list.
Kent S. Johnson was the main presenter, and showed us how Django is used to host the http://www.blogcosm.com site. Without going into details on the business aspects of the site, Kent was able to give us a tour of several of the pages, talk about the RESTful URL formats, the model-view-controller model that’s used, demonstrate some of the code used to describe a model and the actions that can be taken on it, and show us some of the templating language that generates the HTML. The built-in administrative functionality, creating simple CRUD pages based on the model descriptions, was an impressive Django feature.
An excellent meeting, with lots of code and lots of ideas. Thanks to Kent for the main presentation, to our Cambridge brethren for making the long trip, to Bill Sconce for arranging, announcing and MC’ing the meeting, and to the Amoskeag Business Incubator for providing the great venue. Hope to see you all again at next month’s meeting, held on the 27th of December, likely just an informal chat due to the proximity with the holiday.
Riding Rails: Rails 2.0: It’s done!
In the Never-A-Dull-Moment category, David blogs Riding Rails: Rails 2.0: It’s done! and provides a summary of new and improved features. As he said at the recent Railsconf (audio here), Rails 2.0 was not an earth-shaker as much as an evolutionary move. Looking forward to trying it out.
Should you buy software from a web-storefront-only operation?
A client had a demo web site developed by someone else and they were really excited about the interactivity. It was a very rich client application, with drag-and-drop and sizers and interactive widgets. The client wanted my team to use the same platform, which they thought was something-Dot-Net. Once we were finally able to chase down the developer, it turned out to be a commercial Javascript library. We looked up the vendor, and it is a curious site.
They have an online store, one of those generic things with box-shots of a product that’s download only (there must be an add-on for Photoshop or GIMP to make these fake boxes, don’t you think?), an “About Us” page that has the usual mission-statement-ish stuff, but no “Who We Are” or where they are, a “Customer Support” page that lets you submit a ticket online, no history, no searching. The only contacts are email addresses (generic, “marketing,” “legal,” “info” not “bobsmith@example.com”) and an 800-number I have no doubt is an answering service. There’s no online forum. It looks like no one’s home.
Searching about them in Google, there’s their web site, of course. There are a couple of mentions about XSS (cross-site scripting) and a few other exploits posted to the usual security sites, a good sign that someone is actually using the code. A couple of echos of their press releases. And… nothing. No user communities, either a forum on their web site or an ad-hoc third party set of posts. No additional information. No one posting anything, anywhere from @example.com. This is pretty strange.
So, what’s the deal? My best guess is that this is an off-shore operation without any US representation nor tech support, perhaps even no ability to provide support in English. Between a proprietary license and questionable support, I’ve recommended we do some more research and see if some of the open source or openly-available Javascript libraries can fulfill the client’s needs.
Popup panels on mouseover using only CSS
I found this elegant little hack the other day while browsing for something completely different. I see that the code has made the rounds, and appears on sites like xmpp.com and ietf.org, but the credits seem only to lead to other marketing sites harvesting page views and hosting ads. A sample is available at http://www.phlapjaxs.com/demo.html and consists of a span tag defined as absolutely positioned and block-display, which in turn is inside an anchor tag set to position: relative. That means the block will “pop” at the location of the anchor and can display whatever text (or images or other content) is within the span. Spiffy!
Slide presentations: S5 and Google Present
I’ve mentioned and endorsed S5 (the Simple Standards-based Slide Show System, if memory serves) before, as a great way to write a presentation, and at the same time generate slides, handouts and the HTML to post it to the internet, all as the same set of documents. Creating a set of slides in S5 means I don’t have to worry if the machine at the presentation site has a ‘viewer’ as long as they can read standard XHTML and run Javascript. I can post it directly to my web site archive of shows, and carry it on a USB tab in case my laptop decides not to work.
Google has recently announced Google Present as part of their free Google Apps. It’s a pretty cool AJAXy interface familiar to anyone who’s worked with one the many slide programs. One killer feature is that it will import PowerPoint files, even some of the ugly old ones. You can publish them online as I’ve done here with a Y2K presentation from the dFPUG Conference. The import came over with pretty good fidelity, far better than the original HTML export that PowerPoint 9 attempted. So far, so good. But what happens if you’re planning on doing a presentation and can’t trust the internet will be available (important safety tip here, folks: you can’t trust the internet to be available. Murphy has a special place in his heart for presentations)? Even better news: Google Apps also lets you download a copy of this. It comes down as a ZIP file, handy to throw on a USB tab (you should save an unzipped copy, too) and put in a different bag than the one that holds your laptop. It unZIPs to an HTML file and a couple folders holding the CSS, JavaScript, images and supporting files to run the show and runs from a local disk. You could upload this version to your web site, too, and look what you get: a slick slideshow with slides, fonts and graphics that scale to size of the screen (essential when you discover the projector can only handle 800×600!) and redraw pretty snappily.
Finally, S5 has a competitor! This one looks promising.
CentraLUG: 1-Oct-2007: Michael Kazin shows Nagios
The Central NH Linux User Group returns to the Library after a summer hiatus at the Sybase offices in Concord. The monthly meeting of CentraLUG, the Concord/Central NH GNHLUG chapter, happens the first Monday of most months at the New Hampshire Technical Institute‘s Library, room 146, at 7 PM. Next month’s meeting is on October 1st at 7 PM. Directions and maps are available at http://www.centralug.org Open to the public. Free admission. Tell your friends.
At this meeting, Michael Kazin will be presenting Nagios, the Open Source monitoring service. From http://www.nagios.org, “Nagios® is an Open Source host, service and network monitoring program.” Written in Perl and controlled by text configuration files, Nagios offers the ability to alert administrators to a huge number of possible problems with connectivity, speed, or performance. Nagios offers a web interface for close-to-real-time monitoring, email/pager alerts, the ability to launch other programs, etc.”
Michael is a computer consultant at a well-known consultancy working for well-known companies in the military-industrial complex. He is a member of the Greater New Hampshire Linux User Group’s Board of Directors. Previously, Michael helped run the Rutgers University Student Linux User Group and gained his experience with Nagios by monitoring hundreds of machines in the Rutgers Data Center.
Future Meetings: Currently, we have a couple interesting meetings coming up: November: Ted Roche on Cascading Style Sheets, December: David Berube on Ruby, January: Bruce Dawson on low-power Linux computers. As always, meetings are subject to change. You are encouraged to join the low-traffic announcement list to get announcement and cancellation information.