GeoNetwork can run either on MS Windows, Linux or Mac OS X.
Some general system requirements for the software to run without problems are listed below:
Processor: 1 GHz or higher
Memory (RAM): 512 MB or higher
Disk Space: 30 MB minimum. However, it is suggested to have a minimum of 250 MB of free disk space. Additional space is required depending on the amount of spatial data that you expect to upload into the internal geodatabse.
Other Software requirements: A Java Runtime Environment (JRE 1.5.0). For server installations, Apache Tomcat and a dedicated JDBC compliant DBMS (MySQL, Postgresql, Oracle) can be used instead of Jetty and McKoiDB respectively.
The software listed here is not required to run GeoNetwork, but can be used for custom installations.
GeoNetwork should work normally with the following browsers:
 All = Windows, Linux and Mac OS X