Abstract
Flash memory is increasingly being used as a storage medium in mobile devices
because of its low power consumption, fast random access, and high shock resistance.
The type of
ash memory used for bulk storage applications is NAND
ash, which is
organized into physical blocks, each of which contains a set of pages that are accessed
by read and program operations.Here, we describe Hydra, a high-performance
ash
memory SSD architecture that translates the parallelism inherent in multiple
ash
memory chips into improved performance, by means of both bus-level and chip-level
interleaving.

Chapter 1
Introduction
Flash memory is a non-volatile memory chip that can be electrically erased and re-
programmed.A solid-state drive (SSD) is a data storage device that uses solid-state
memory to store persistent data. Solid State Drive (SSD) are distinguished from
traditional hard disk drives (HDDs), which are electromechanical devices containing
spinning disks and movable read/write heads. SSDs, in contrast, use microchips which
retain data in non-volatile memory chips and contain no moving parts.Hydra, is
ash
memory solid state disk architecture which exploits the parallelism of multiple NAND

ash memories to enhance system storage performance.

Chapter 2
Data Storage Devices
2.1 Hard Disk Drives
A Hard Disk Drive is a non-volatile secondary storage device used for storing
digital data. It consists of rotating platters mounted on a motor driven spindle and
enclosed in a protective enclosure.Data is magnetically read and written on the platter
by read/write heads that
oat on a lm of air above the platters. The main features
of HDD's are:
 Data Transfer Rate : A 7200 rpm hard disk could transfer data at a rate of
70MB per second
 Error handling : Uses Error Correcting Codes such as Reed-Solomon Error
Correction
 S.M.A.R.T. - Self-Monitoring, Analysis, and Reporting Technology, which
measures characteristics such as operating temperature, spin-up time, data error
rates etc.