2009
05.11
05.11
2009
05.10
05.10
Sungjin Lee, Keonsoo Ha, Kangwon Zhang, Jihong Kim, and Junghwan Kim,
Link -> FlexFS: A Flexible Flash File System for MLC NAND Flash Memory,
To appear in Proceedings of USENIX Annual Technical Conference (USENIX ATC), San Diego, USA, June 2009.
what is Flex-OneNAND
benefits of Flex-OneNAND
| 3-chip MCP Solution | 2-chip MCP Solution | |
|---|---|---|
| memory combination |
 |
 |
| target application | Ultra High Density Device | 512MB ~ 2GB Navi. & Music Phone, DSC |
technical feature comparison
| items | OneNAND | MLC NAND (1) | Flex-OneNAND (2) (MLC Area) |
Flex-OneNAND (SLC Area) |
|
|---|---|---|---|---|---|
| product nature |
Bootability | YES | NO | YES | |
| P/E Cycle | 100K | 5K | 10K | 50K(TBD) | |
| ECC/EDC | 1bit ECC (2bit EDC) |
N/A | 4bits ECC(5bit EDC) | ||
| performance | Page Size | 2KB | 4KB | 4KB | 4KB |
| Read Performance |
108MB/s | 25MB/s | 67MB/s | 87MB/s | |
| Write Performance |
17MB/s | 4.4MB/s (1 plane) 8MB/s(2 plane) |
5MB/s(1 plane) | 15MB/s(1 plane) | |
note :
- (1) 50nm MLC(No cache), (2) 60nm Flex-OneNAND
merge performance comparison
Time delay of worst case during copy-back operating
worst case : Partially written two blocks are merged onto one free block
Flex-OneNAND feature highlight
| cost effective | Large Block Structure & MLC based NAND Core |
|---|---|
| enhanced performance | X16 Synchronous Burst Read/Write(66Hz) Superload/ Cache Program |
| reliability | Embedded automatic 4bit ECC, 5bit EDC |
| smart security | Normal OTP Block(128KB) and User Controlled 128KB OTP Block (1st Block OTP) |
| fixed pin count | 16 Address Pins Regardless of Density Increase |
| data protection | Three Stages of Data Protection (Lock/Unlock/Lock-Tight) |
| automatic boot up | Internal Boot Loader with 1KB XIP at Power Up |
| features | FBGA(LF)/ Bottom Boot Multiplexed Interface (Data-Address) available Operating Voltage 1.8V/ 3.3V |
| line-up | 4Gb, 8Gb(DDP), 16Gb(QDP) |
2009
05.10
05.10
Tolerating File-System Mistakes with EnvyFS
Lakshmi N. Bairavasundaram, Swaminathan Sundararaman, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
To appear in the Proceedings of the Usenix Annual Technical Conference (USENIX ‘09)
San Diego, CA, June 2009.
Available as: Abstract, Postscript, PDF, BibTex