SSD Academy SSD and HDD Terminology & Architecture Don Barnetson Sr. Director of Marketing

Outline

First and Second Generation SSDs (2007, 2008): Share the same interface as HDDs PC does not know whether it is talking to an SSD or HDD Key to understanding SSDs is understanding the HDDs that they are replacing SSD and HDD architecture is significantly different Introduction

Key HDD Terms - Internals Platter The physical spinning disk using in an HDD; data is written to the surface of the platter (top or bottom).

Key HDD Terms - Internals Sector A slice of a platter that contains the minimum addressable (R/W) portion of an HDD.

Key HDD Terms - Internals Track Thin concentric circular strips that contain sectors on the surface of a disk drive.

Key HDD Terms - Internals Cylinder All tracks accessible without moving the head assembly.

Key HDD Terms - Internals Head The device that writes data to and reads from the surface of an HDD. Each head services one side of one platter.

Key HDD Terms - Internals Blocks the intersection of a track and a sector is called a block – its address is specified by providing the cylinder, head and sector #.

Key HDD Terms - Internals Logical Block Addressing A way of addressing blocks that simply numbers them linearly rather than providing a cylinder, head and sector #. This scheme is generally replacing the legacy block addressing scheme although both are supported on current SSDs and HHDs.

SSD Block Array Flash

HDD Block Array

SSD Block Array HDD Block Array

Key HDD/SSD Terms - Interface Parallel ATA (PATA) 40 Pin interface – increasing generations increase clock rate & functionality Operates at up to 133MB/s Very low power, but consumes a large # of pins Approaching EOL – 2009/10

Key HDD/SSD Terms - Interface Serial ATA (SATA) Serial: 4 Pin I/F + grounds 1.5 Gb/s (aka SATA-I) – 125MB/s once overhead inc. 3.0Gb/s (aka SATA-II) – 250MB/s once overhead inc. 6.0Gb/s (aka SATA-III) – 500MB/s once overhead inc.

Key HDD/SSD Terms - Interface PCI Express (PCIe) v2.0 500MB/s per lane Very low power & broad HW support

SSD Architecture Overview NAND NAND NAND NAND Controller NAND NAND DRAM SATA

NAND Flash – the Media NAND Plane n Cache NAND Plane 2 NAND Plane 1 Interface

Controller + DRAM NAND NAND NAND NAND NAND NAND DRAM SATA SATA DRAM NAND I/F Back End Buffer Micro Controller ECC FIM FIM FIM Controller

Controller + DRAM SATA DRAM NAND I/F Back End Buffer Micro Controller ECC FIM FIM FIM

Mechanicals Simplest part of the SSD – replicate mechanical form factor of HDD 1.8” vs. 2.5” form factor Connector – uSATA, ZIF, LIF, etc.

Architecture Conclusions SSD: Three key elements NAND Flash Memory (Media) – Reliability Store Bits Controller (Brains) – Make NAND Flash look like HDD Mechanicals (Form Factor) – Allow an SSD to mate to a system

Summary

Visit the SSD Academy for more information www.sandisk.com/ssd © SanDisk Corporation ABOUT SANDISK SanDisk Corporation, the inventor and world’s largest supplier of flash storage cards, is a global leader in flash memory – from research, manufacturing and product design to consumer branding and retail distribution.  SanDisk’s product portfolio includes flash memory cards for mobile phones, digital cameras and camcorders, digital audio/video players, USB flash drives for consumers and the enterprise, embedded memory for mobile devices, and solid state drives for computers.  SanDisk is a Silicon Valley-based S&P 500 company, with more than half its sales outside the United States.