Research And Implementation Of The Blu-ray Jukebox Cache Management Mechanisms

Today, data storage and retrieval is a hot topic. A lot of social production activities areexpanded around the storage and retrieval of data. With the development of Blu-ray, opticaljukebox, as a mainstream storage device, attracts more and more attention, due to its largecapacity, low price, high security, etc. It is used in the applications of hospitals, e-governmentand many other fields.This paper is based on the project "Blu-ray Disc management system". It chooses thecache module to be object of study, and gives an implementation. Caching system is a veryimportant component in optical jukebox, which eases the bottlenecks on the response time,due to the drawback in mechanical structure of optical jukebox, and leads a greatimprovement in system efficiency.This paper analyzes the characteristics of the caching of Blu-ray jukebox, studies andanalyses specifically on hit ratio of the cache. To make a compromise between the overheadand hit ratio of cache, the paper proposes a replacement algorithm--Disk-Based LeastRecently Used Algorithm (DB-LRU). As an improvement of the traditional LRU algorithm,DB-LRU inherits the speediness and efficiency of LRU, meet the physical characteristics ofoptical jukebox, but also solve the cache pollution of LRU to some extent. According to therelevance of data in the same disk, DB-LRU groups the caching data by disk, and executes theLRU algorithm among the groups. According the experiment, it makes comparison amongFIFO algorithm, the LRU algorithm DB-LRU algorithm on the hit ratio under different accesspatterns. DB-LRU gets better performance than LRU in term of the hit ratio and cachepollution. The DB-LRU algorithm matches the characteristic of optical jukebox, which lays thegood foundation for the improvement of the cache module in the future.