A broadcast pause and resume system may simultaneously read and write data to a disk memory by using separate read and write heads which are driven by separate controllers. In this way, information may be read from and written to the same disk at the exact same time, improving the simultaneity of read...http://www.google.com.hk/patents/US6937813?utm_source=gb-gplus-share專利 US6937813 - Digital video storage and replay system
