Technology and other Fantasies

Hibernate and auto-generated timestamps

2009-04-27T14:06:32Z

I've started using the object-relational mapper Hibernate recently. After studying the book "Introduction to Hibernate" by Minter/Linwood for a couple of days (not the most entertaining and inspring programming book I've read...) and trying examples, I felt ready to put my new knowledge to use. My first project was to convert an existing web application from using my own custom/proprietary O/R mapping to Hibernate, so it could be extended more easily and to be able to use one of the ready-made caches that come with Hibernate. It worked out well - even though creating the mappings caused me some headaches at times - and once you know Hibernate you absolutely don't wanna go back to the "manual" way.

]]> Then I started a fresh project, with a clean database. Just like in the previous project, I needed to have timestamps for "created" and "last updated" on my objects. In the old project, the database was already set up with on update CURRENT_TIMESTAMP, which makes the database update the timestamp automatically when the row is updated. But since it wasn't obvious how Hibernate would set this up in the database from the definition in the mapping and since I wasn't really crazy about database magic and depending on specific database features, I was looking for other solutions. I read about Hibernate's and features, which looked like they did just what I needed, and also help improve locking.

It seemed like a piece of cake to use Hibernate to generate the timestamps with the element inside the of the mapping document. I changed the existing "updated"- to a , but surprisingly that made the XML unparsable. The editor in Eclipse already complained with the red cross next to the class element and when running on the server I got an InvalidMappingException: Could not parse mapping document from resource...). It took me quite some time to find out what the problem was, but after taking a closer look at the DTD, I realized the order of the elements was important and wrong in my mapping. The element needs to be just after the element. Once I changed that, the mapping could be parsed and Hibernate did it's job!

ShareThis button in MovableType 4

2009-02-23T11:34:42Z

ShareThis is a nice addition to any web page. Instead of adding links for Digg, Delicious, Reddit, Myspace, Facebook, etc etc to your page and and coding a "send this article to a friend" function yourself, you can add the ShareThis button, which does all of the above (and more). When a user clicks on the button, a window is opened that lets you choose how you want to share this page: Via social web, blog post or sending email/IM/SMS.

To add this button, you just have to insert some Javascript code into your web page. The URL is detected by the script and sent to the ShareThis server. This is fine as long as you want to share this exact page. But it's not ok if you want to share a specific part of a page, for example on a blog. Your blog always has the same URL, but the posts are changing constantly. Fortunately, every post has a unique URL, by which it can be reached directly. And ShareThis has a pretty flexible API that lets you set the URL you want to share.

Here's how to add the ShareThis button to a MovableType 4 blog:

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Register at ShareThis, get the base code from their customization tool. It looks something like this:

This code provides the base functionality for the ShareThis button.

Paste that (your) code into the header template between and , so it will be included on every page. Save.

Go to the template(s) of the page where you want the ShareThis button. This would normally be the entry-related templates. Paste the following code into the place where you want the button to appear, e.g. within the asset-footer div tags to have the button below an entry.

Rebuild your blog and the ShareThis buttons will appear.

Hard disk crash and Time Machine

2008-12-30T10:58:58Z

It happened shortly before christmas. I was working with my MacBook (on the sofa) and all of a sudden I could only move windows around. Couldn't switch to another program, couldn't actually work with the program I had open. Very strange, I thought, this never happened before with my trusty OS X. The only thing I could do was to turn off the machine. Then it didn't want to reboot any more. On closer inspection, I realized that the disk was making a strange repetitive clicking noise and was constantly changing its rpm. Great, broken disk!
I had been working for 4 days since my last backup. Lucky guy, you might think, but NO! 4 full days of coding work were lost, and of course in those days I managed to solve a lot of important problems. Later when I made up the lost work, I realized that I remembered quite well what it was, so I was finished in less than half the time, and it might even be better than the first version. But we will never be able to tell.

So I had to get a new disk. Top priorities for me are energy efficiency (especially in a notebook), low noise, and great performance/price ratio. This meant the very large disks and the very fast disks were out of the question. I settled with a Samsung HM320JI with 320 GB, which is a 5400 rpm model, so it runs cooler and quieter than the faster 7200 rpm drives. The speed is great, too, compared to my previous 120 GB drive.

Here's what I did to be able to work again:
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Replace the old disk with the new one. This is very easy now compared to the iBook. You can get the MacBook DIY hard drive exchange manual from Apple.

Boot from the Mac OS X DVD and select the option to restore from a Time Machine Backup. Connect your external disk that contains the backup.

Once the backup is detected, you can select what data you want to restore.

The restore process takes some time, depending on how much data needs to be copied. In my case it took about 1,5 hours.

Time Machine worked flawlessly. So a couple of hours after the crash I could work again. The worst was to redo the work lost since the last backup. If you have Mac OS X 10.5 (Leopard) and are not using Time Machine yet, I would strongly recommend you do so. Hard disks do break sometimes, even if it never happened to you or anyone you know. You can count on it. Time Machine backs up automatically when you connect the external disk, so there's nothing to think about.

Linux server management and SysCP

2008-10-31T14:30:50Z

Since a couple years I'm hosting websites on a my own dedicated server. This gives a lot of freedom and flexibility, you can install whatever daemons you like, you have plenty of disk space and you can amortize some of the cost by hosting other (customer) sites on your server or even make a business this way. Secondly, you have to be able to efficiently manage your server's configuration. Editing system configuration files directly not only requires in-depth knowledge of most parts of a Unix/Linux server, it is also time-consuming and brings a certain risk of making mistakes which might take down the whole server. And if you host other people's sites, those people must also be able to configure their domain, databases, email-settings and so on without interfering with the rest of the system.

For the configuration and administration, there are a bunch of web-based apps out there that give you a nice browser UI and hide the way the system is configured under the hood. You just add domains, email addresses and databases without having to know how Apache configures virtual hosts, how Courier authenticates users, how access permissions are managed in MySQL and so on. Some of these apps are commercial, some are free, and they all have different scopes of use.

Webmin (BSD license) is such a tool, and it lets you configure just about everything on your system. But it's not primarily designed for hosting environments, where you have to be able to manage settings per customer and where customers should be able to log in with restricted rights to manage their own domain and ftp and mail users. There is some progress in this direction, but others do it much better.
For my scenario described above, apps like Confixx or Plesk work great, but they are commercial software and quite expensive. That's ok if you have a lot of paying customers, but for smaller installations, the monthly license fee for Plesk is already as high as the hosting cost of a simple server. If you are lucky however, your hoster already includes a Plesk license in your hosting contract at no additional charge.

I have worked with Confixx for a while, and then had to switch to Plesk. Yes, I had to, because Confixx was discontinued and when I switched from one server to a faster one, only Plesk was available. I thought maybe it's not so bad because Plesk is made by the same company (they were bought by Parallels later) and it is the official successor to Confixx, so there should be an easy upgrade path. The reality was quite different. There was a migration tool from Confixx to Plesk, but that failed to migrate my server's data. So I had to manually re-setup all the customers, domains, email-addresses etc. Eventually I had it running and the people could start getting used to the new user interface.
While Confixx was mostly focused on pure virtual host configuration, Plesk goes beyond that and also lets you do some low level administrative tasks, like setting up cron jobs and making backups. I thought the backup feature was particularly useful. Until one day I had to reinstall someone else's server and it turned out that Plesk's restore tool (pleskrestore) was not able to restore a backup made with Plesk's backup tool (pleskbackup), using the same version of Plesk!. It turns out I wasn't the first to encounter this. There were posts on the support forum that described the same problem, from last year, and there was no solution. Shame on Parallels for not being able to fix this. They shouldn't offer this backup tool if the restore is not working.

So my experience with these tools has been quite mixed. As long as they work, they work great, but it's very hard to tweak the configuration beyond what's offered by default. This and the unsure migration path for the future made me look for alternatives. There are a couple of free tools that can be seen as direct replacements for Plesk. The more known are VHCS / ispCP Omega and SysCP. You can try them out, they have demo versions online. VHCS seems to have more features at first look, but there are plugins for SysCP as well that add extra functionality. ispCP Omega is based on VHCS and has the best looks of the three.
Currently I'm migrating another server and the new hoster doesn't give me Plesk, so I chose to go with SysCP, as there seems to be the most activity in the support forum and regular software releases.

The installation is a piece of cake for Debian with apt-get. The configuration is a bit harder, but well documented. Follow the step-by-step guide and you'll have SysCP up and running in a couple of hours or less. Unfortunately, they missed to mention one important setting, which seems to be essential: In "IPs and Ports" you need to enable "Create NameVirtualHost statement", "Create vHost-Container" and "Create ServerName statement", otherwise SysCP will not be reachable after you set up the first vhost.
So far I'm quite happy with SysCP, it works fine and everything seems much more transparent than back in the closed-source Confixx and Plesk. (It's not very beautiful by default but I'm sure that can be changed.) During installation you also learn where the configuration is kept in the system and you'll know exactly what to back up and how to restore it.

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MacBook and Kensington Lock

2008-10-31T14:21:19Z

What did I read this morning... Kensington locks don't work with the new MacBooks! Bummer. Could Apple really design the Kensington lock slot in a way that it doesn't fit a Kensington lock? I couldn't believe it, so I tried for myself:

]]> As you can see, the lock fits just fine. No problems whatsoever getting it in or out. Don't believe what you read.

Alien technology - the new MacBook

2008-10-29T16:21:08Z

It arrived here yesterday: The brick, aka Apple MacBook Aluminum or Unibody MacBook. I'm sure you've read about it somewhere. Isn't it amazing how much press this company gets when they introduce a new product? I mean in relation to their market share. But that's only surprising at first sight, because Apple has been and still is a pioneer when it comes to computers and user interfaces. Even if only few people buy Apple's products, they have a huge influence on other manufacturers' products.

Apple's switch from PowerPC to Intel in 2006 was exciting in that their computers got a nice speed-bump and were more competitively priced. But it also made the computers somewhat more PC-like. Not that they got that bad, not at all, but some of the charme of the old times was lost. For example, ventilator noise or waiting for the system to wake up from (hibernation) sleep mode was something hardly known to Mac users until then. But they really made up for this with the great Mac OS X and the beautiful designs of their machines. But Macs and PCs are since then apparently easier to compare.

Since the competition is not sleeping, PCs have improved, too. It was time for Apple to come up with something to set themselves apart from the rest again, and the new Aluminum MacBooks are exactly that. Here's my review.
]]> More photos

Unibody case
The case is machined from a massive block of aluminum, so it's missing most of the usual gaps where parts are joined. When I first saw pictures of the MacBooks, I thought they were renderings, they looked so perfect. But the actual MacBook looks the same. Perfect lines, perfect finish. At the same time it's lighter than its predecessor, the white (or black) MacBook, and it's very sturdy. Not a bit of flexing or even squeaking noises. Macs used to be good in this respect compared to most PCs but now they are lightyears ahead.
The aluminum seems quite thick on the edges, which makes the Kensington lock slot very trustworthy. I have heard stories about locked (PC-)notebooks being stolen, with the lock just ripped out of the case. This won't work here.
LED-backlit display
The display is the same 13.3" as in the previous model. A size I like very much as it keeps the notebook small while the resolution of 1280x800 pixels is high enough to fit enough content. It's significantly brighter than before and dimmable over a greater range, in other words the lowest setting is lower in brightness than the lowest setting of the previous model - nice if you sometimes work in total darkness.
The display got thinner and a lot stronger. When you take it on one corner to close it, there is no more lateral flexing.
Keyboard
The keyboard looks just like the previous MacBook keyboard in that the case is indented as much as the keys are high and the keys extrude freely by themselves. The layout is also exactly the same and just like the small Apple wireless keyboard. Great if you have several computers and keyboards and every one feels the same. One small difference though: The keys seem to go down a little deeper and a little softer as on the previous MacBook (at least my 2006 model).
Trackpad
This is one of the phenomenal improvements. If you don't look at it and just use it, you won't notice a difference. And after clicking you think: How did I click, there's no button?! It's simple, you press down the whole trackpad, but it feels just like the button that used to be there. Leaving the thumb laying on the trackpad while using your index finger for pointing doesn't bother the trackpad at all but when you are using two fingers simultaneously. The new trackpad supports some new gestures: Zooming in and out like on the iPhone, swiping with three fingers for page up/down (or back/forward in the browser), swiping with four fingers for Expose and switching application and finally the two-finger twist for rotating an image (so far I have only seen this one work in iPhoto, while the other functions work across the board).

I took some unboxing pictures the MacBook and made some detailed shots. You can look at them here.

Even louder than the yippies about all the great improvements were the complaints that some things are missing and the computer press seems to love to bash Apple for that. Here's a look at the two most important points of criticism:

Display is glossy and glossy only
I understand that you could get the previous MacBook Pro with a matte display as a built-to-order option. But the MacBook has always had a glossy display.I was skeptical about the glossy display at first, but since the first day I had my white MacBook, I enjoyed the new display. It was a big improvement over the matte display of the iBook. Yes, sometimes you get reflections, but with a small movement (turning or tilting the display a little) you can get rid of them. When inside, this almost never happens, or you don't notice it. I guess that's because your eyes focus on the screen at let's say 50 cm distance, but the objects that are reflected are at least twice that distance from the eye.
Missing Firewire port
This is something that also hurt me at first. I've been using (or trying to use) USB peripherals since the beginning (version 1) and there was so much pain involved. Somehow that attached itself to the word USB for me and everytime I hear USB some of those feelings come back. So the Firewire port on my first Mac was a great relief. Things just worked, external disks were seemingly as fast as internal disks, 2.5" external disks didn't need a power supply and the target mode was great back in the days when you had no WiFi or Fast/Gigabit Ethernet to copy some files over.
Now where are we? USB 2.0 has been around for a while and works ok. Still we love Firewire. Now Apple has dropped it from the MacBook. I wanted to know what that meant for me and made some real-world performance tests. I used my external Samsung 3,5" 1 TB disk (Pleiades USB 2.0 / Firewire 400 case) and connected it via Firewire and USB 2.0 to both my old MacBook 2006 1,83 GHz and the new MacBook Aluminum 2.0 GHz and copied (read & write, 2 runs each) 940 MB of data in 63 files and one large file of 1,9 GB. Here are the results:

MacBook white Firewire average: 23,7 MB/s
MacBook white USB 2.0 average: 26,7 MB/s
MacBook alu USB 2.0 average: 32,7 MB/s

In general I thought those transfer rates are rather low, but now I'm not worried anymore about the missing Firewire port as USB 2.0 performs very well on the new MacBook. Of couse if you have a Firewire video camera or need to daisy chain several devices it's a different story.

All in all I think this MacBook is a great step forward. I really recommend going to a store and checking it out in person. Should you buy one right now? Yes if you really need a notebook, but no if you can wait a little longer. I think the price for the entry level MacBook Aluminum is a bit high. The first MacBook in 2006 was much more competitive in price when compared to a PC notebook (CPU, RAM, hard disk, etc). The Unibody case is probably driving up cost pretty much in the beginning. I expect that with the first refresh the price will go down (they'll probably drop the white MacBook then).

I got a blog!

2008-10-29T14:34:08Z

Here it is, my blog. Who would have thought this day would come. Since a while now I have been playing with the thought of starting a blog, but never did. Some things that have stopped me until now (and you might recognize some):

Not enough time
I guess this is a common problem and I haven't found a solution for it yet, besides slowing down the rotation of the earth. That would make the days longer and probably add the missing hour to the day we need for blogging (or other things?). But in a time when everyone is so concerned about the well-being of our planet, this would be hard to get global consensus on.
Not sure which language to use
I am German, so German is my mother tongue and it is the language I prefer for expressing myself. Even though there are over 100 million native German speakers (mostly in Germany, Austria, Switzerland), and probably also that many that have learned German as a foreign language, what is that compared to the 1000 million that speak English? The bigger your audience, the better, especially if the topics are of interest to anyone in the world. On the other hand, Germans would probably not read my blog if it was in English and if they can get similar information in their own language. What a dilemma!
Who's gonna care?
Why should anyone read my blog? It's one in millions (even though most of them were started and then died after a couple of entries - is that gonna happen to me?).
Can I make it interesting enough? Can I write well enough?

So then why did I start now? Good question and I'm still not really sure myself. But more and more often I have the urge to say my opinion, after reading certain news articles in the mass media, be they of technical or political nature. And more and more often I feel that I should share some information with others that might be useful to them.

The technical side of blogging was pretty clear to me since a couple of years, when I started developing my mobile blog client BlogPlanet. Believe it or not, I had this nice tool available to me and most of the time a state-of-the-art mobile phone, but didn't use it beyond test posts. As a publishing system I'll use MovableType, which I've always been a fan of, even if that goes against the global trend to Wordpress.

Even though I'm usually of few words, I'll try to be more verbose in my blog and I'll try to enjoy it. It might be a good compensation to coding. If I'm boring you, say so, the comments feature will be available. But of course I'll be very happy to receive your positive feedback as well.