Non-busy access system for bubble memory chips

Non-busy access (NBA) bubble memory systems to improve request throughput by the use of a shortest access time first (SATF) request scheduling algorithm are considered for on-chip cache organized 4 Mb bubble memory chips. The NBA bubble memory system consists of multiple bubble memory units, each of which is realized by adding a marker RAM, an address switch and a data buffer to a conventional bubble memory unit for request queuing. Computer simulation results proved that the NBA bubble memory system can serve more than 900 requests a second, while the average response time is held to less than 16.5 ms. It is concluded that the NBA bubble memories for application to database index files can have several tens of times higher throughput performance than the conventional bubble or magnetic disk memories.