A New Hash Algorithm Exploiting Triple-state Bucket Directory for Flash Storage Devices

Abstract

Recently, the flash storage device becomes more important to the mobile consumer electronics that supports various functionalities because of its portability and reliability. The capacity of the flash storage device is becoming larger and its price is going down due to the mass production of the Triple-Level Cell (TLC) flash memory. Since TLC flash memories are very cheap, they are widely deployed in the mobile flash storage device although its durability is poor. In addition, it is difficult to handle the large-scale flash memories with limited memory resources in the mobile flash storage device. Therefore, TLC-based flash storage device requires to internally optimize the write and erase operations with small memory resources. This paper proposes a new hash-based mapping algorithm, which reduces the redundant write and erase operations and uses only a few memory resources, for the mobile flash storage device. The proposed hash algorithm also guarantees uniform performance regardless of various workload patterns. Through various experiments with related works, this paper shows the superiority of the proposed hash algorithm(1).