Dimajix Developer Blog

While all people are talking about Windows Vista, lets look back in time:

The 80s really were a weird time, with a very strange taste for clothing. And a real laughable highlight is the Promotional Video for Windows 386 promoting the wodners of multitasking, with the best part coming at minute 7 after a boring start. Some people even wouldn't be surprised if it turned out to be sleazy porn scene.. It shouldn't be a surprise that you will not find many hits for the directory David Vik on google.

I am so glad that the 80s are over.

A short intermission with a status report of Magnum. Finally I put up a public SVN repository which can be reached under svn://dimajix.de/magnum. The repository has public read access for everyone and is synched with my private development repository every night, so it is always almost up-to-date.

The most important feature that will be included in the next release version is full reflection. This means that one can access the complete type information including classes, structs, unions, enums, methods, functions, fields and variables via a dynamic interface at runtime. You can even invoke any method or create new instances of arbitrary objects. This should make it rather easy to make up a small scripting language which can access all types defined in Magnum.

This is a really huge undertaking, but most of the really hard stuff is already working (you can download the newest version via Subversion, as indicated above.). Still missing is some intelligent automatic argument casting for method-invocation (so you do not have to care about the exact needed types), some fixes for non-public class members and - most importantly - the integration into the build system.

The really special about my implementation of the reflection is that you will not need to modify your source-code (at least I try really hard to avoid the need of changes to the source code for which reflection is to be generated.) to make your classes accessible via reflection. The meta-compiler, which reads in all headers and creates some cpp files containing the needed runtime information for reflection, is also outstanding in that it uses a generic XML-based language to transform the meta-information parsed from the original header files into a new text-based output file. The metacompiler is not tied to my implementation of reflection and can (and will) be used for many other automatic header-transformations. For example one could write an XML template that generates serialisation code for arbitrary classes (this actually shouldn't be too hard). Other possible uses include the generation of COM or .Net wrappers (or for any other scripting language), etc.

According to ars technica, Bill Gates showed off his newest product, the Windows Home Server as part of his keynote last Sunday at the CES. The WHS is a small device intended to be the central server for home users for storing their photos, music etc. Paul Thurrot has a small preview of this server and a hardware implementation done by HP (Microsoft only delviers the operating system). On OSNews there has been a debate for the need of such a product.

I predict that the Windows Home Server will be a big success for Microsoft, and I will try to elaborate on the reasons: Nowadays we live in the so called "information age", that is after industrialisation, information is the new driving force in out culture. More and more people have have multiple computers at home (you do not want to know how many I own) and other electronic devices like digital cameras, media players, digital video recorders etc are already standard equipment in many households.

This means that digital content and properties replace traditional values in our life. This also means there is a new need for protection of your personal investments - ten years ago, you could mainly lose your possesions in terms of a physical loss. Nowadays more and more important and valuable data is stored on various computers at each home. This imposes two problems: First you want a centralized storage for all your digital data (photos, movies, music, documents etc), and second you want a secure backup of all your data. Many people become increasingly aware of the first problem, but the second is the really important one. In former times, you only lost part of your values if - for example - a CD got scratches or was stolen.

But nowadays if your harddisc crashes, you probably will lose a lot of irretrievable data like your private email etc. So you wish that you had a backup of all your data, or even better a centralized storage that is protected against hardware faults by some redundancy.

These are just the reasons why a home server makes sense for a lot of people today. One can argue that there are already a lot of good and affordable NAS boxes out there, but most of them are not more than simple NAS boxes (one exception would be Infrants product reportoire) that don't offer comfortable backup utilities or are too complicated for the average user. This is why I see espceially Windows Home Server to be a success - if done right and with the help of Microsofts massive marketing forces.

For me, I probably won't buy a Windows Home Server, because I want something more professional - I want to have a blindingly fast RAID server with tons of storage, support for different file protocols (NFS comes to my mind), although the hardware specs of HPs machien are promising: 1.8 GHz AMD Sempron paired with 512MB of RAM. This should offer twice the performance of Thecus N5200 NAS solution, which is already by far the fastest affordable home NAS out there (although with many firmware limitations and problems).

You might wonder what the girls at Sun expect from a boy friend. You can find the answer in a small spot at YouTube:

• availability


• reliability


• redundancy

Currently I am thinking of replacing my (rather new) ReadyNAS NAS server by a more powerful self-built server. Although the ReadyNAS is a very nice device with very good support from Infrant, it is still too slow for storing all remotely mounted user directories for my Linux and Mac box. Plus I am thinking of using a iSCSI volume for all user directories on my Windows box.

My ideal server would contain an Areca SATA controller with 16 channels and 15 disks in hot-swap carriers running in a RAID-6 plus one or two fast gigabit controllers. So much for the hardware.

But another important aspect is the software of course. Currently I would opt for OpenFiler as operating system for the server. OpenFiler is based on Linux and supports all features I want, except for efficient snapshots. Snapshots are a wonderful thing, they allow to keep an old state of a file-system without the need to do an explicit backup (although one still should backup ones data because of the risk of hardware faults). OpenFiler implements these snapshots using LVM (Logical Volume Manager), which in turn implements snapshots on a Copy-on-Write base. This snapshot implementation has two main drawbacks:

• You have to allocate space for the snapshot on your disks.


• The more snapshots you have, the slower gets your system .

And this is exactly the point where Suns filesystem ZFS comes in. ZFS also supports snapshots, but as it seems in a much more efficient way. You do not need to preallocate space for the snapshot and it seems that there is no performance penality by using them. So I'd love to use ZFS together with OpenFiler - but ZFS currently is only available in Solaris with a Linux port under the way. But I guess it will take more time for the Linux port to finish and to be integrated into OpenFiler than I want to wait with my new NAS server.

Snapshots really are the reasons why everyone wants ZFS on Linux. Okay, at least this is my personal top reasons why I want to see it soon. Or a port of OpenFiler to Solaris

I am a big fan of the english avantgarde director Peter Greenaway, who made the films (among many others)

• The Draughtsman's Contract (1982)


• A Zed & Two Noughts (1985)


• The Belly of an Architect (1987)


• The Cook the Thief His Wife & Her Lover (1989)


• Prospero's Books (1991) (one of my favorite films)


• The Pillow Book (1996)


• 8 ½ Women (1999)

Now Peter Greenaway has an exciting new project called The Tulse Luper Journey, which is more than only a film. It is a story about a fictive man called Tulse Luper (who already appeared in some of Greenaways previous works), who was imprisoned for his whole life - mistaken for someone important, a spy, a lover, an artist, a writer and an observer. Luper has packed a total of 92 suitcases in his life reflecting his subjective view of the history of the 20th century. The complete project includes three feature films, a TV series, 92 DVDs, CD-ROMs, and books.

The Tulse Luper Journey also contains an online game which is still going. You can win a Tulse Luper DVD box and a journey round the world.