Method of reducing disc workload in a video-on-demand system by seamlessly replacing memory-based video streams with disc-based video streams, and visa-versa

A method, for use in a video-on-demand (VOD) system that comprises—1) a digital computer which is coupled to a semiconductor memory, 2) a disc storage module, coupled to said computer, that stores several videos, and 3) a network interface circuit (NIC) which couples said computer to a plurality of viewing devices;

• the VOD system seamlessly provides switching video streams between the disc-based video streams and the semiconductor memory-based video streams during a viewing period such that no interruption or discontinuity in the video streams that are sent to the viewing devices;
• said method including the steps of:
• sending to said NIC, multiple streams that are memory based of a first one of said videos, and disc-based video streams of a second one of said videos, wherein the number of streams of the second video exceeds that of the number of streams of the first video, where each disc-based video stream is sent in blocks from said disc storage module into a respective buffer in said semiconductor memory and is sent therefrom to said NIC, and where each memory-based video stream is sent in blocks directly from a single region of said semiconductor memory, that stores said second video in its entirety, to said NIC without the use of any separate buffers in said semiconductor memory and without the use of said disc storage module;
• determining, in said digital computer, that said disc-based video streams which are actually being sent by said sending step are causing a read workload on said disc storage module that is too large based on a predetermined criteria, and that there is insufficient unused storage space in said semiconductor memory to store said second video in its entirety;
• seamlessly replacing, in response to said determining step, all of said memory-based video streams for said first video with disc-based video streams so that there is sufficient unused storage space in said semiconductor memory to store said second video in its entirety;
• and thereafter,
• transferring said second video, in its entirety, from said disc storage module to said semiconductor memory;
• and,
• seamlessly replacing all of said disc-based video streams for said second video with memory-based video streams.