Update system
The Mana World plans to be an constantly expanding game, with new features, maps and other game media being added all the time. This constant addition requires some way to distribute new material. The Mana World up to this point has been using a monthly release cycle to update the game, but this distribution method suffers in the following ways:
- Data redundancy - This is a major concern for those who have slower connections to the Internet. For each update, all existing data is also downloaded.
- Not frequent enough - Players want new material as fast as they can get it. Players like a fast updated, dynamically changing game world in which they can immerse themselves - any stagnation can lead to player loss.
- Complicated - Making a new client release involves a complete ritual of providing the necessary binaries and updating many websites. For content updates or tuning this process can be skipped.
- Breaking compatibility - Each time new content is added, the game will break for anybody using an older client. When content updates are done separately, very often a forced client update can be avoided.
The Mana World wishes to address this by using an in-built update system which will automatically download the latest game media. By doing this, the second and third points noted above are eliminated. This update system should provide the following features:
- Smart updating - the updater should be able to find files which need to be updated and update them, without trying to update files which are already up to date.
- Cumulative patches (Optional)
- Media updates - should be able to fetch new and updated game media.
- Executable updates - should be able to update the binary executables appropriately.
Regarding the last topic, we discussed it a bit, and thought that first of all, we need a version checking, so that everyone is informed about a new release. In windows we were evaluating the possibility of directly replacing the binary, while this won't be possible in GNU/linux. I guess we will continue with monthly releases, and will discuss in this article only static data updates. --ElvenProgrammer 02:08, 4 Jul 2005 (PDT)
Update format
Updates come in compressed archives (.zip files). They are easy to create and allow individual files to be read directly from them (we use PhysFS for this). Initially, the client will retrieve an ordered list of archives that it should load, for example:
tmw-base-1.0.zip tmw-base-patch-1.1.zip tmw-tonori-region-1.0.zip
The client will check whether all the listed zip files are present in its data directory, and attempt to download any missing ones (see update distribution below). Once downloaded, it will put each archive in the virtual file system provided by PhysFS. Once a data file is loaded, the archives are search bottom to top so that the file will be loaded from the last archive that provided it. This allows us to patch big data archives with a small archive that contains just the modified files.
Any files present in the data directory that are not in the list can be considered to be old, and could be cleaned up by the user with the click of a button.
This ordered list could contain protocol information for file retrieval and information concerning the platform which the patch can be used. Such a list could look like:
win32 http://themanaworld.org/updates/tmw-base-binary-win32-1.1.zip osx http://themanaworld.org/updates/tmw-base-binary-osx-1.1.zip all ftp://themanaworld.org/updates/tmw-maps-tonori-1.3.zip all http://themanaworld.org/updates/tmw-gfx-items-1.1.zip
It is also suggested that the updates can be used in the configuration director (~/.tmw) on UNIX based platforms, as root priveleges would be required to install the updates correctly otherwise. Nym 23:56, 4 Jul 2005 (PDT)
- I think updating the binary should stay out of the scope of the data updating system, as it is very OS specific. The data updating system can work consistently acros all platforms, so there is no need to indicate platform in the file list. I'm not sure about sending full URLs yet, as long as we're using http/ftp I think it'd be better to set up one or two mirrors and optionally allow the user to choose where to download from. --Bjørn
Update distribution
Updates must be distributed fast and effectively, providing a decent throughput even when the update server is under a high load. The Mana World development team has decided that the Bit Torrent protocol will be utilised for update distribution. BitTorrent is a distributed peer-to-peer protocol which utilises the bandwidth of all users. For more information about Bit Torrent, see the Bit Torrent Introduction.
To easily utilize to the Bit Torrent protocol, one of the following libraries can be used:
- libbt - C
- libtorrent - C++
- libTorrent - C++
Yeah I know we already choosed for BitTorrent, anyway we shouldn't discard HTTP/FTP both because some people don't want to be forced to share their bandwidth or if they're having problems. Someone also asked for the possibility to stop sharing patches (in case updater is built-in). A noticeable example is WoW updater which both allows for bitTorrent or HTTP downloads. And the patch sharing is limited to the time you download the patch (until you don't press "Play game!" I guess). A deeper evaluation of band usage and lag problems should be provided. --ElvenProgrammer 02:08, 4 Jul 2005 (PDT)
Because both libbt and libtorrent still seem immature and have annoying dependencies, I would suggest to hold off from BitTorrent for now and use libcurl to retrieve the updated data files through HTTP or FTP. --Bjørn 12:06, 4 Jul 2005 (PDT)
- I agree, libcurl is at least used by libbt so if we're going to use it, it will be required anyway. I'd like also to say that libcurl it's really easy and could help us to create the HTTP/FTP updater in no time.--ElvenProgrammer 12:55, 4 Jul 2005 (PDT)
- "Q: Is anyone got it work under windows? (maybe any plan on porting?) A: Haven't heard of anyone doing so and i don't really care about the win32 platform and its lack of posix support. Unless someone pays me it'll propably not happen. ;)"
- Just to let you notice windows is not supported. --ElvenProgrammer 08:39, 20 Sep 2005 (CEST)
