Buffer caching is the caching of disk blocks in memory to avoid costly disk accesses by exploiting spatial and temporal locality. Most buffer cache algorithms [1, 2] are designed to improve the system performance from a holistic perspective

This paper proposes buffer cache architecture. The proposed model consists of three units – main buffer cache unit, pre-fetch unit and LRU Evict Unit. An algorithm is proposed to retain the evicted entry from main buffer cache unit in the LRU Evict Unit thereby giving it a second chance of access. On subsequent access in the LRU Evict Unit, the entry is promoted to the prefetch unit to accommodate more entries in the main buffer cache unit. On access in the pre-fetch unit, an entry is fetched into the main buffer cache. The LRU replacement policy is used in all the units. The proposed model is compared with buffer cache architecture with LRU replacement algorithm. The performance is comparable for sequential input where as 3 % improvement in performance is seen for random input.

The increasing use of computers for saving valuable data imposes stringent reliability constraints on storage systems. Reliability improvement via use of redundancy is a common practice. As the disk capacity improves, advanced techniques such as disk scrubbing are being employed to proactively fix latent sector errors. These techniques utilize the disk idle time for reliability improvement. However, the idle time is a key to dynamic energy management that detects such idle periods and turns-off the disks to save energy. In this paper, we are concerned with the distribution of the disk idle periods between reliability and energy management tasks. For this purpose, we define a new metric, energy-reliability product (ERP), to capture the effect of one technique on the other. Our