Contents

SSD

ssd基本介绍

SSD Architecture

  • SSD is a complete, small system where all componets are soldedred on a PCB and is indpendenty packaged
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  --------------------------------------------------------------------------------
  |                                                                               |
  |                                         SSD                                   |
  |               -----------------------------------------------------------     |
  |              |                                                           |    |
  |  ------      |  ----- -----      -----------------         ----------    |    |
  | |      |     | |     |     |    |                 |       |          |   |    |CH0  ----- 
  | |      |     | |     |     |    |                 |       |          |   |---------|Flash|
  | |      |     | |     |     |----|                 |       |          |   |    |     -----
  | |      |     | |     |     |    |    ARM Cores    |       |          |   |    |
  | | PCIE |     | |PCIE |NVMe |    |                 |-------|  Flash   |   |    |
  | | Host |---- | |Layer|Layer|    |                 |       |Controller|   |    |CH1  -----
  | |      |     | |     |     |    |                 |       |          |   |-------- |FLASH|
  | |      |     | |     |     |     -----------------        |          |   |    |     -----
  | |      |     | |     |     |       |          |           |          |   |    |
  | |      |     | |     |     |       |          |           |          |   |    |
  | |      |     | |     |     |    --------   ----------     |          |   | .  |
  | |      |     | |     |     |   |Internal| |   DRAM   |    |          |   | .  |
  |  -------     | |     |     |   | Buffer | |Controller|    |          |   | .  |
  |              |  ----- -----     --------   ----------      ----------    | .  |
  |              |                                  |                        |    |
  |              |                                  |         ------------   |    |
  |              |                                  |        |            |  |    |
  |              |                                  |        |other logic |  |    |CHn -----
  |              |                                  |        |            |  |------- |FLASH|
  |              |                                  |         ------------   |    |    -----
  |               ----------------------------------|------------------------     |
  |                                                 |                             |
  |                                                 |                             |
  |                                           -----------                         |
  |                                          |           |                        |
  |                                          |   DRAM    |                        |
  |                                          |           |                        |
  |                                           -----------                         |
  |                                                                               |
  -------------------------------------------------------------------------------

Controller功能

  • 提供一个接口在host和Flash之间
  • 处理来自host的数据,提高数据传输效率以及数据的可靠性。 Controler中包含wear leveling, Garbage colletcion, Bad Block magnagement,ECC,flash interface。

DRAM

  • DRAM主要用来作为L2P(Logic to Physical) table mapping,一般配置是1GB NAND FLASH空间对应1MB DRAM
  • FW code本省也需要dram空间来运行
  • 多余的DRAM空间可以作为host write buffer以及其他的table(比如:Bad Block table, RBTree for good/availbale blocks)
  • 帮助实现奇偶校验

其他部分

  • voltage supervisor 防止2powerloss and brown outs。如果检测到有power loss,那么fw对打断一些特殊操作。

  • Backup capacitance super caps 可以保证整个drive backup(比如dump entrie dram) tantalum caps 提供一段时间保证program comman完成。

  • NOR FLASH

    1. BOOTLOAD(Enumerates the nand, initialized the DRAM)
    2. Manufacturing data
    3. Page Table pOINTER(nand lbock that contains the L2P table)
    4. Error/evnet logs