It is worth noting that a combination of browse and search interface may further help the end-user. This results in such records being highlighted and displayed at the top of the relevant browse sections. As the number of records in a subject gateway database increases, the techniques used to manage it may need to change. Manual checking of records is likely to be feasible only for a small database. An automated link checker can be provided, which will confirm the validity of the URLs in all the records in a subject gateway on a configurable, regular basis.
Resource updates .
There is a danger that the descriptions of resources held in subject gateways will become out of date as the resources themselves are updated. It should be possible to develop robot-based tools that check for potentially significant' changes to the resources that are described in the gateway, automatically warning resource cataloguers of the records that are likely to need updating. This could be done in a simple way by checking for significant changes in the sizes of the remote files. Review-by dates . By embedding a review-by date into every resource description you can automatically be notified that a record hasn t been checked recently.