A massive, free, virtual classroom system is being planned by Polytechnic University to serve Hong Kong's 1,200 primary and secondary schools. The virtual classroom - where children learn without having to meet each other or their teachers face to face - will be based on a makeshift system built to provide online learning while schools were closed during the Sars outbreak last year. It will serve as a supplementary resource for normal times, and a backup education system during a crisis. To help design the system, a survey will be conducted next year on the schools' electronic needs. Questionnaires will be sent to headmasters in January, said Stephen Mak Wing-kai, associate professor of the university's department of building and real estate. The database of 64 terabytes - about 64 trillion bytes - is backed by a $24.61 million Jockey Club grant. It will enable video and audio streaming for pre-recorded classroom presentations, offer data-crunching services for marking students' work and exams, and help track students' reading skills. It could also lighten students' schoolbags by providing hard-disc space to store e-textbooks and notes. Construction of the system is due to start in June and is expected to take three years. A team of 20 technicians will work closely with teachers and students on the development of course materials. Last year's system offered online learning facilities to 30 schools; 10 adopted virtual classrooms. 'Last year, we responded to the crisis of Sars. This time we are planning ahead in case crises occur, so as to prevent the paralysis of the education system,' said lecturer Lennon Choy Hung-tat. He said the team hoped eventually to extend the system to the entire education community.