Design And Implementation Of An I/O Scheduling System Of File-backup Jukebox

With the development of optical disc technology, The use of jukebox has becomeincreasingly common and the Application is more and more widely. The jukebox has thecharacteristics of long data retention time, few environment requirement, relatively wellaccess speed and has its own aunique advantage as the tertiary storage device of thehieraichical mass storage system.The I/O scheduling system of jukebox as part of a file backup system is of a greatinfluence to the storage performance of the whole system. Based on analisising thepractical application environment and requirement, combined with existing I/O schedulingmethods of jukebox, designed the I/O scheduling system for the file backup jukeboxsystem.The system is also designed with the idea of dynamic scheduling, to request timelyreceiving and handling. The same time, the task queue as a basis for scheduling with thepriority, assignments and wait scheduling times is sorted. While the system is Relativelyfree, replacement algorithm to select the CD-ROM drive, to avoid the disc again swapped.The consideration of the waiting time so that the system can improve the efficiency of thesystem while taking into account the fairness of the user.The system is implemented in the Linux environment, the core idea of the schedulingalgorithm has been completely achieved, the realization by means the POSIX messagemechanism to deal with the request to send and receive. The implementation andperformance of the system function was verified through simulation tests.