Newsletter Volume 1 Livecd
- Luca Casagrande
What is a LiveCd
As Wikipedia reports, Livecd is a "generic term for an operating system distribution that is executed upon boot, without installation on a hard drive. Typically, it is stored on bootable media such as a CD-ROM (Live CD), DVD (Live DVD), USB flash drive (Live USB), among others." By using this technology, users can get a "taste" of a full GNU/Linux box without fighting with any setup or installation. Once the LiveCd has been booted, everything is loaded in RAM, keeping the hard disk safe. Of course, once the machine shuts down, every change is lost.
There are many applications that can be satisfied through the use of a livecd:
- Running your favorite system anywhere you can find a PC. With a Pen Drive to save your data, you will have a perfect survival kit.
- For teaching purposes: During a workshop, your audience can have anything you think is appropriate to increase the learning process.
- Using an old machine: liveCd can be run on an old machine and also without a HD!
- Spreading data: it's a very cool way to distribute your work. You deliver your work (for example output of complex elaboration) and all applications needed, configured to appreciate it best!
Limitations of a Livecd
Inside a livecd we have the kernel, drivers, WM, and all the applications required for a working environment. Of course, it is rather impossible to put all the drivers that would suit all the machines that have been created. It can happen that, during boot, the CD stops or something else goes wrong (e.g. missing lan detection). Thanks to the work of a lot of people (in primis Knoppix) we have very good software that detects hardware during boot but, like every software application, there can still be bugs. As you can understand, the idea of having a universal machine is a high expectation and the road to achieving this is still long.
On the other hand, no information is saved while working in the LiveCd environment. If this is a favorable aspect (e.g. keeping your hard disk safe), it can be tedious from another point of view. A solution is to use a Storage Device (like a USB HD, for example) to store all your output. This approach can also be used to save configuration files, so that you can keep your settings after rebooting.
LiveCd and open source geospatial software
LiveCd can be a valid tool if applied to open source geospatial software.
An example of an application of liveCd and GIS FLOSS is to run a workstation that will allow users to explore data inside it or, for example, in a remote Postgis DB. Old machines can be used to make access points to the database and can be set up with a viewer that is always available (as Internet Points do with a browser), allowing the saving of data on a storage device.
During the FOSS4G 2007 at Lausanne, we used 2 LiveCds during seminars (ka-Map and Grass 3d). We also allowed participants to immediately test what they had just see in the slideshow. Once the workshop ended, they were able to keep their liveCd and use it at home or at their office. This is a good example of the great potential of a liveCd deployed for Educational purposes.
Our liveCd will always try to offer users the following:
- Up to date software with every main official release
- Included guides, documents and tutorials
- Good hardware compatibility
We decided to use Catalist: the same tool that the Gentoo Release Engineering Team uses.
This choice is based on 2 main reasons:
- To use a system that will keep the updating stage fast and safe
- To allow the customization of everything inside the CD
Our first release for 2007 contains this software:
- QGIS 0.8
- GRASS 6.2.1
- PostgreSQL 8.1.5
- PostGIS 1.1.4
- GDAL 1.3.2
While writing this abstract, we are waiting for the release of the 2007.1 Qgis 0.8.1.
Future Development and Tasks
Our goal is to keep the CD updated by creating new versions on a regular schedule, or at least as soon as major updates or included software will be released.
At the moment we are working on two tasks:
- An Installer for the livecd
- A server edition with mapserver and some webgis applications
The installer will be accessible through an icon on the desktop. The installation process will guide the user to the setup of the GNU/Linux distribution on his/her computer. Hard disk installations will allow better performance and the possibility to update all packages, thanks to the core of the Gentoo Linux ( http://www.gentoo.org/ )system.
The server edition will target a server machine with minimal graphical support but with a fully-featured set of applications to offer OCG Web Services and UMN Mapserver frontends (ka-Map, Open Layers, p.Mapper, ecc.).