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: Open Source BlogOpen Source Image Archiving: Exif, IPTC, XMP and all that
Related to this hack started taking a serious look at the available standards and Open Source tools for adding meta data to images, in the context of building archives of digital photography. With further prompting from reading this (Hey! MS are adopting someone else’s standard!), dumping some notes…
Photo Archiving: The Golden Rule
Store metadata in the image.
Actually should be more precise about the word metadata here – there are essentially three significant types of metadata when in comes to digital images, when it comes to who created it and where it’s stored.
First; the stuff your digital camera attaches to the image when you take a picture (e.g. camera make, time the picture was taken, exposure etc.), second; meta data you manually add to an image, typically at the time you download images from the camera to your PC (e.g. where the picture was taken, a description, keywords, name of the photographer etc.) and third; “grouping metadata” – how a collection of images relate to each other (e.g. they were all part of a single photo shoot or they are all family pictures). For the purposes of this discussion, the first two types of metadata can be regarded as a …
OSCON 2006: TimeTravel Tables in PostgreSQL
A. Elein Mustain is a veteran developer of Ingres, Illustra, and Informix, and is the author of the weekly PostgreSQL General Bits column.
Elein showed how to use timestamps to keep an audit trail of all changes in your DB. With this technique, you never actually delete records, you just give them an end date. Multiple copies of a record (again, with timestamps for each one) also allow you to track edits. (This is a pretty standard approach, especially in ‘validated’ environments, or in government-regulated industries.)
The value of using Postgres here is in the advanced features like triggers that you can use with your deletes and updates to offload the work needed to maintain this ‘time travel’ system — rather than forcing your app logic to keep up with all of it.
You can also use PostgreSQL’s views to query the database for only the current data, or write procedural functions to query the state of the database at a particular point in time in the past.
Elein has her slides available online here.
OSCON 2006: Big Bad PostgreSQL
Theo Schlossnagle is a principal at OmniTI Computer Consulting, working in the areas of scalable internet architectures, database replication, and e-mail infrastructure.
This talk was on converting a really large (over 3 terabytes, largest table is 1.8 billion rows) data warehouse database from Oracle 8i to PostgreSQL. The reason for the conversion was to save in licensing costs. They wanted to move their Oracle licenses over from the data warehouse DB to use them on the online transaction processing (OLTP) system.
The reason for choosing Postgres over MySQL was that Postgres has a much longer history with the kind of advanced features he needed. They needed (and were able to hack PostgreSQL to get) the following features:
1. Data partitioning (spreading tables over multiple drives)
2. Large selects (50-million-row return sets, over 100GB of data)
2. Incremental COMMITs for really, really long queries
3. Replication
The bottom line was that with some patience and creating thinking, they were able to migrate a really humongous database to PostgreSQL from Oracle, and ended up saving themselves $500,000 USD in licensing costs. A pretty good chunk of change.
Theo has put his slides up here.
Track Your Hacks with CVS
The following is republished from the Tech Times #130.
Quite by coincidence, three times in the past week I have had to hack the code of some open source software that went into the site I was working on. First I had to modify phpBB to include an embedded calendar on the home page of a private forum I administer. Next I made some custom tweaks to the code of the K2 theme for Wordpress. Finally, I had to hack phpAdsNew to produce XHTML Strict output.
In each case, the hack required me to actually modify the code of the software. Obviously I prefer not to do this, because when the next release comes along the updated files will overwrite my hacks, and I’ll need to implement them all over again.
Normally I’d just document my hacks someplace and grumble about the lack of customization features in the software, but three times in a week was too much. Let me show you how I solved the problem using a common development tool in an unconventional way!
CVS (Concurrent Versions System) is a system for tracking changes made to files in a project over time, potentially by multiple developers, …
OSDC 2005 Wrap Up
The second Open Source Developer’s Conference, held in Melbourne this week, can be most simply described as a massive geek-fest.
It’s probably unfair to compare it to the Web Essentials conference that I attended earlier this year, because OSDC is – in the organizers’ words – “created by developers, for developers” whereas Web Essentials has less of a grass-roots base.
But I’m going to make the comparison anyway, as I think it does provide a useful measuring stick. As far as I could tell, OSDC differed from Web Essentials in five aspects:
- speakers were not paid. This meant that the presentations varied wildly in terms of quality and relevance. There were a number of excellent presentations that appealed to the entire audience, but there were also quite a few talks that were amateurish and about completely obscure topics that would only interest a handful of people.
- presentations were much shorter. Apart from a 60-minute keynote presentation at the beginning and end of each day, all talks were only half an hour long. The more experienced speakers made good use of this limited time, but for some speakers it resulted in their 73 slides being whizzed through far too quickly for anyone to …
Things to Do With Firefox 1.5
Firefox 1.5 is here, and available for all to download and use.
Many of you no doubt have tried out the Beta and Release Candidate builds. Here’s a list of things to do and see with Firefox 1.5.
- Use the back and forward buttons to see the dramatic increase in rendering speed resulting from Firefox’s new “fastback” cache.
- If you installed one of the Beta or Release Candidate versions, you could wait until Firefox updates itself using its new incremental update system.
- When tabbed browsing, grab the tabs with your mouse and drag them to the order you want.
- Press Ctrl+Shift+Delete to bring up the “Clear Private Data” window to clear private data such as history, cache and cookies.
- Go to websitedoesnt-exist.com to check out the new, non-obtrusive error messages.
- Check out “Help > Report Broken Website” to see how easy it is to report a Website that doesn’t work in Firefox.
- Install Firefox on your Mac and see how easy it is to migrate your profile information from Safari.
If you’re still itching to get involved with Firefox, you could consider the following:
- Get your Webcam ready and head on down to SpreadFirefox to take part in some sort of celebration.
- Catch up with Firefox related …
One Year and 100 Million Downloads Later, Firefox
SpreadFirefox.com have a gallery of screenshots up to celebrate Firefox’s first birthday.
In its first year of official release it has enjoyed more than 100 million downloads (check out the celebratory photo gallery) and is now tipped to have reached 10% market share (see Asa Dotzler’s excellent blog).
One year after releasing 1.0, version 1.5 is just around the corner, with the second release candidate build available for download now. I have been following the patches and submitting bugs for a year now, and am very proud that some bugs I reported have been fixed in the upcoming version. Submitting bug reports to the Mozilla crew has been an impressively positive and rewarding experience, due to its supportive community and team of developers and patchers.
One of the most exciting, to me, updates in Firefox 1.5 will be its incremental updates system. Updates can be downloaded automatically in the background, and installed the next time the browser restarts. What’s more, the updates are incremental – no more downloading the entire 6 MB each time a minor update is released.
If you decide to go download and install a release candidate build …
MySQL 5.0 stable release
MySQL 5 is out. This stable release is now recommended for production use, so if your installation of MySQL 4.1 is getting dusty (or worse yet, if you’re still on 4.0), now might be the time to look at updating your installation.
This release of MySQL effectively brings it to feature parity with enterprise databases like MS SQL Server and Oracle, with many new, long-awaited features:
Stored Procedures and SQL Functions
Embed a portion of your application’s business logic directly into your database to improve performance of frequently-needed data manipulaton operations.
Triggers
Further offload business logic from your application. Respond to changes in your database by executing custom operations in response to events like row insertions, deletions, updates.
Views
Define particular table columns or joins that are accessible to certain users without granting them full access to sensitive data in the relevant tables.
Cursors
The database can keep track of your application’s current position in a large result set, so that you don’t need to cache such large result sets in your application.
Information Schema
Access information about your database tables through the virtual information_schema database.
XA Distributed Transactions
Perform transactions (multi-step operations that must succeed completely or not happen at all) across multiple database servers, or even non-database systems.
SQL Mode
Switch modes …
Zimbra: Gmail and Exchange meet Open Source, Java and AJAX
Zimbra is either the coolest thing I’ve seen this month, or too good to be true. I haven’t decided which yet.
Previously known as Liquid Systems, Zimbra is the new name of the company, as well as its flagship product: an extensible open-source client/server system for managing email, contacts, and calendaring that can be accessed with either a slick, cross-browser, AJAX-powered user interface, or via desktop applications like Microsoft Outlook, Mozilla Thunderbird/Sunbird, Apple Mail/iCal, and others.
The server that powers all this, Zimbra Collaboration Server, is written in Java, and sits upon familiar open source components like a MySQL database, a Postfix Mail Transfer Agent (MTA) (with SpamAssassin and ClamAV for anti-spam and anti-virus by default) and a Tomcat Web Application Server.
Although the services provided by Zimbra (mail, contacts, and calendaring) are all accessible with desktop applications (see above) via the open standards that exist for these things, Zimbra also provides its own cross-browser, AJAX-laden, Web-based user interface. This UI supports many of Zimbra’s “extra” features, such as message tagging, unified search, email rendering plug-ins (e.g. linking your company’s invoice numbers to your order tracking system when they appear in email messages, or integrating services …
Software Freedom Day – September 10
Software Freedom Day is this Saturday, with events around the globe. The event hopes to promote the value to be found in the use of open source and free software.
Some press reports suggest much of the activity will occur in and around Asia with less exposure in Europe and the Americas. Of course, open source fever has caught on seemingly more widespread in Asia and Australia – however – there are no shortage of FOSS adopters elsewhere with events slated for the weekend.
The concept surely helps newcomers of all stripes as there is a focus on several levels:
- Personal users
- Small and medium business
- and the corporate enterprise
The teams are encourage to hold workshops and labs with hands on access to open source platforms as well as growing the unique social ‘community’ bond found in the open source sphere.
