Comparison

News Database

The nntpcache stores its active database using a dbm database, while the News Cache uses the NVHash class of the Non Volatile Container Library.

The overview database is stored by the nntpcache using its own memory mapped database similar to the News Cache. However, nntpcache has the disadvantage that it uses multiple files for a single overview database. This puts higher demands onto the file system.

The article database is managed in exactly the same way. Both caches use the format used by the INN news server.

Functionality

In its current release nntpcache has the following features that are currently not supported by News Cache:

• Support for access control based on the client host and the client hostīs identd. The identd reports the name of the user that initiated the connection.
• Support for filtering and censoring based on newsgroups and articles for specific clients. Filtering eliminates the newsgroups transparently, while censoring informs the client that the newsgroup or article has been censored. Censoring is not fully implemented in the current release.
• Unknown commands can be passed on to the news server. However, if this feature is turned on, the censoring and filtering of articles cannot be guaranteed since it may be possible to retrieve those articles using an unknown command.

The News Cache provides the following features not supported by nntpcache:

• Prefetching of newsgroups and articles. This means that a specific newsgroup and its articles are retrieved from the news server without a request from a client. The decision which articles have to be transferred are based on configuration files and heuristics.
• The possibility to read Usenet News offline. The News Cache allows to retrieve newsgroups during times with Internet connectivity. These newsgroups may then be read by news clients even if no connectivity to the news server exists.
• The News Cache can either be run as standalone daemon or it can be started using the inetd daemon, while nntpcache can only be started as standalone daemon.
• News Cache supports to filter specific newsgroups. We do not provide a content based article censoring mechanism, because this can restrict the right of free speech.