A NEW microcomputer system will be used to link all schools with the Education Department to enable more efficient administration by the end of the year, the Director of Education, Mr Dominic Wong Shing-wah, said yesterday. He said the $27.79 million computerisation programme would link the department and all 900 government and aided schools. A total of $10 million has so far been spent to equip 390 schools with the computer system, while $1.6 million has been used to train staff. Another 500 schools will receive a microcomputer and relevant training by November. Mr Wong said the department's administrative circulars issued to schools would be replaced by an electronic system through which school responses could be known instantly. ''Administrative manpower, time and paper could be saved with this system,'' he said. Meanwhile, the department has joined a similar integrated computer network service launched by City Polytechnic. Other users of this ''CityLink'' service, which started yesterday, includenine secondary schools. City Polytechnic is inviting all secondary schools to join the system. Polytechnic assistant director Mr John Dockerill said the system would enable users to gain access to services like electronic mail and information retrieval. He said the polytechnic would fund half of the overall cost of the system while the annual charge to schools was $2,000, including the cost of maintenance of the equipment provided by the polytechnic. ''If a school uses their own personal computers, the annual charge is $1,200,'' he said. Mr Wong said teachers could obtain information about the department's educational materials and the past Hongkong Certificate of Education Examination papers through CityLink. He said the department would continue to subscribe to CityLink even if its microcomputer system was implemented. This was because CityLink provided different information to the department's future system.