چکیده: کاهش ابعاد ترانزیستورها در نسل جدید حافظه­های فلش و رهسپار شدن آن ها به سمت حوزه­­­های طراحی نانومتر منجر به عدم صحت در برنامه­ریزی و پاک کردن اطلاعات در این طراحی­ها شده؛ درنتیجه قابلیت اطمینان در ذخیره­سازی اطلاعات به چالشی مهم در ساختار این نوع حافظه­ها تبدیل شده است. جهت مقابله با چنین چالشی در کنترل کننده این نوع از حافظه­ها از کدهای تصحیح خطا­ی bch استفاده می­شود. دو نکته­ اساسی در...

Flash memory has gained tremendous popularity in recent years. A variant of flash, referred to as NAND flash, is widely used in consumer electronics products, such as cell-phones and music players while NAND flash based Solid-State Disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. Computer architects have recentl...

Flash memory has gained tremendous popularity in recent years. A variant of flash, referred to as NAND flash, is widely used in consumer electronics products, such as cell-phones and music players while NAND flash based Solid-State Disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. Computer architects have recentl...

We propose an efficient dynamic hash index structure suitable for a NAND flash memory environment. Since write operations incur significant overhead in NAND flash memory, our design of index structure focuses on minimizing the number of write operations for hash index updates. Through a set of extensive experiments, we show the effectiveness of the proposed hash index structure in a NAND flash ...

In this work, we develop novel file system, FRASH, for byteaddressable NVRAM (FRAM[1]) and NAND Flash device. Byte addressable NVRAM and NAND Flash is typified by the DRAM-like fast access latency and high storage density, respectively. Hierarchical storage architecture which consists of byte-addressable NVRAM and NAND Flash device can bring synergy and can greatly enhance the efficiency of fil...

NAND flash memory is a nonvolatile storage that is often used for its advantages of small size, non-mechanical, shock resistance, and low power consumption. With the recent drop in its price, NAND flash memory is on the verge of taking place of hard disk drive. Depending on the number of bits stored in a single cell, flash memory can be divided into SLC (single-level cell) NAND and MLC (multi-l...

In this paper, we attempt to replace NAND Flash memory with PRAM, while PRAM initially targets replacing NOR Flash memory. To achieve it, we need to handle wear-leveling issue of PRAM since the maximum number of writes in PRAM is only 10. Thus, we have proposed PRAM Translation Layer (PTL) to resolve endurance problem for a PRAM-based storage system. We modified FlashSim to support both PRAM an...

This chapter is to introduce NAND flash channel model, error correction codes (ECC) and signal processing techniques in flash memory. There are several kinds of noise sources in flash memory, such as random-telegraph noise, retention process, inter-cell interference, background pattern noise, and read/program disturb, etc. Such noise sources reduce the storage reliability of flash memory signif...

The cost-per-bit of NAND flash memory has been continuously improved by semiconductor process scaling and multi-leveling technologies (e.g., a 10 nm-node TLC device). However, the decreasing lifetime of NAND flash memory as a side effect of recent advanced technologies is regarded as a main barrier for a wide adoption of NAND flash-based storage systems. In this paper, we propose a new system-l...