Computer Fundamentals 简明教程
Computer - NAND Flash Memory
What is NAND Flash Memory?
NAND 闪存是一种非易失性存储器，不需要有规律的电源供应来工作和保存数据。它的主要目标是高速地读取和写入内存的数据，并最大化其存储容量以存储大尺寸的数据并降低成本。
NAND flash memory is a non-volatile memory which doesn’t require a regular power supply to work and retain data. Its main goal is to read and write data from and to the memory very fast and maximise its storage capacity to store data large-size data and reduce cost.
NAND 闪存将数据存储到存储器块中，当电源关闭时，金属氧化物半导体就会激活电荷以保持存储器单元功能。NAND 存储器单元由两种类型的门组成：控制门和浮动门。这两个门用于调节数据流。要对一个单元进行编程，就需要向控制门施加一个电压电荷。通常来说，NAND 闪存在数码相机、MP3 播放器、USB 闪存盘、智能手机、平板电脑和笔记本电脑中。
NAND flash memory stores data into memory blocks, when the power supply gets off the metal-oxide semiconductor activates charges to keep memory cells functional. NAND memory cells are made up of two types of gates: control and floating gates. Both gates are used to regulate the flow of data. To program one cell, a voltage charge is applied to the control gate. Generally, NAND flash memory has digital cameras, MP3 players, USB flash drives, smartphones, tablets and laptops.
Where NAND Flash Memory is Used?
NAND 通常在存储卡、USB 闪存盘和固态硬盘中。NAND 闪存最广泛的用法是在我们家和办公室中的手机、笔记本电脑和平板电脑中。它也用于交通信号灯、数字广告面板、乘客播音系统、显示器或任何其他可能包含 NAND 闪存的数据传输和保存数据的 AI 应用程序中。
NAND is commonly found in memory cards, USB flash drives, and solid-state drives. NAND Flash is most widely used in cell phones, laptops and tablets in our homes and offices. It is also used in traffic lights, digital advertising panels, passenger announcement systems, display devices or any other artificial intelligence (AI) application where data transfer and retain data is likely to include NAND Flash.
NAND 闪存正在不断演变以满足现代数据存储的需求。它的坚固性、速度和成本效益使其成为日新月异的存储器存储技术领域中的关键参与者。
NAND flash memory is evolving to meet the demands of modern data storage. Its robustness, speed, and cost-effectiveness make it a key player in the ever-changing world of memory storage technology.
Why NAND Flash Memory is Important?
与传统的硬盘驱动器相比，基于 NAND 闪存的设备具有抗震性、极佳的耐用性和应对极端压力和温度的能力。与 HDD 不同，它们没有任何运动部件，因此适合用于产生振动和震动的系统。NAND 还提供了快速读取访问时间，在处理大量数据时至关重要。总体来说，NAND 最适合需要大量数据存储的应用程序。它提供了更高的密度、更大的容量和更低的成本。它具有更快的擦除、顺序写入和顺序读取速度。
When compared to traditional hard disk drives, NAND Flash-based devices provide shock resistance, great endurance, and the ability to handle extreme pressure and temperature. They have no moving parts, unlike HDDs, and are therefore suitable for systems that make vibrations and shake. NAND also provides rapid read access times, which are critical when processing large amounts of data. Overall, NAND is best suited for applications that require large amounts of data storage. It provides higher densities, larger capacity, and reduced costs. It does speedier erases, sequential writes, and sequential reads.
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Most widely used in Consumer Electronics − It is an essential component in a wide range of electronic gadgets, including smartphones, tablets, digital cameras, and portable media players to store data.
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Critical for Solid-State Drives (SSDs) − SSDs, which use NAND Flash Memory, provide considerable performance over traditional hard drives.
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Portability − Its high storage density enables the development of lightweight storage devices such as USB flash drives and memory cards, which are required for portable data storage and transfer.
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Power Efficiency − NAND Flash Memory requires less power than mechanical hard drives, which is critical for battery-powered devices like laptops, smartphones, and tablets. This efficiency increases battery life and improves the user experience.
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Reliability and Durability − NAND Flash Memory, unlike traditional hard drives, is more resistant to physical shock and damage since it contains no moving parts. This makes it perfect for transportable and hard applications that require high reliability.
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Scalability and Cost-Effectiveness − The technology continues to advance, providing larger storage capacities at lower costs per gigabyte. This allows for the cost-effective storage of large amounts of data, which provides benefits for both consumers and enterprise applications.
Features of NAND Flash Memory
NAND 闪存的一些主要特征如下 −
Some of the key characteristics of NAND Flash Memory are as follows −
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Non-Volatile Memory − NAND flash memory is non-volatile, which means that it retains recorded data without the use of a battery or other power source which makes it suitable for long-term data storage. Such memories can preserve data for a long period without being damaged.
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High Density − NAND flash memory is available with high storage capacity in a small physical space. Its high-density feature makes it usable in SSDs, USB drives, and memory cards.
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Durability − It can write and erase data n number of times which makes it durable.
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Performance − NAND flash memory allows fast read and write operations.
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Cost-Effectiveness − NAND flash memory is cheaper per gigabyte as compared to other types of memory.
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Reprogrammable − NAND flash memories are that they can be programmed to meet the user’s needs. The programmable IC chips may store any type of data, from documents to films and allow users to use them whenever required.
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Faster Write and Erase Time − NAND flash memory is fast read and writes data; due to this feature, it is most widely used in the application areas where data writing operations are required. It is also a distinguishing property of NAND flash memory that takes less time to erase its contents.
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More Storage − NAND flash memory can store up to 2TB storage devices. Modern NAND flash memories are launching to store large-size data.
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Low Manufacturing Cost − Its manufacturing cost is comparatively low.
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Data Integrity and Reliability − Advanced error-correcting codes (ECC) and wear levelling algorithms are used to improve data integrity and extend memory life.
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Scalability − NAND Flash can be scaled to extremely high capacity, which is a driving factor for large-scale data storage solutions.
How does NAND Flash Memory Work?
NAND 闪存通过一系列涉及使用浮栅晶体管存储和检索数据的过程来操作。其整体工作方式取决于其结构、数据存储功能以及读写数据的方式。以下是不同阶段的简要说明 −
NAND Flash Memory operates through a series of processes that involve the storage and retrieval of data using floating-gate transistors. Its overall working depends on its structure, data storage functionalities, and reading and erasing data. A brief description of the different phases is as follows −
Structure
NAND 闪存由存储数据位的存储单元组成。每个单元由一个浮栅晶体管组成，在控制栅极和衬底之间有一个额外的栅极（浮栅极）。存储器中的这些单元分为页面，这是最小的写入单元。页面分为块，这是最小的可擦除组件。
NAND Flash is made up of memory cells that store bits of data. Each cell is made up of a floating-gate transistor with an additional gate (the floating gate) between the control gate and substrate. These cells in memory are divided into pages, the smallest writing units. Pages are divided into blocks, the smallest erasable components.
Storing Data
浮动栅极可以存储代表数据的电荷，其中电荷的存在或缺失标志着该单元存储二进制“0”或“1”。要写入数据，可以对控制栅极施加高电压，从而导致电子穿隧通过薄氧化层并陷入浮动栅极中。晶体管的阈值电压根据存储在浮动栅极上的电荷而变化，从而使该单元能够表示不同的状态。
The floating gate can store an electrical charge that represents data; the presence or absence of this charge marks whether the cell stores the binary '0' or '1'. To write data, apply a high voltage to the control gate, which causes electrons to tunnel through the thin oxide layer and become trapped on the floating gate. The threshold voltage of the transistor varies according to the charge stored on the floating gate, allowing the cell to represent different states.
Reading Data
要读取数据，可以向控制栅极提供电压。流经晶体管的电流量由存储在浮动栅极中的电荷决定。传感器电路检测电流流动并根据晶体管的阈值电压识别存储的数据（“0”或“1”）。
To read data, a voltage is delivered to the control gate. The amount of current flowing through the transistor is determined by the charge stored in the floating gate. The sensor circuit detects current flow and identifies the stored data ('0' or '1') based on the transistor’s threshold voltage.
Erasing Data
NAND 闪存无法删除单个比特或页面，而是擦除整个块。要擦除一个块，可以在相反的方向提供高电压，从而从浮动栅极中去除电子并将单元恢复到其默认状态（通常为“1”）。
NAND Flash memory cannot delete individual bits or pages; instead, it erases entire blocks. To erase a block, a high voltage is supplied in the opposite direction, removing electrons from the floating gate and restoring the cells to their default state (typically '1').
Types of NAND Flash Memory
常见的 NAND 闪存存储类型包括 SLC、MLC、TLC、QLC 和 3D NAND。以下是它们的简要说明 -
Common types of NAND flash storage include SLC, MLC, TLC, QLC and 3D NAND. A brief description of these is as follows −
SLCs
SLC 是单电平单元的缩写。它是较旧的 NAND 闪存之一，每个单元仅表示一个二进制数字（比特）。SLC 或单电平单元每个单元包含一个比特。SLC 提供最佳的耐久性，但它也是最昂贵的 NAND 闪存存储类型。
SLC is an abbreviation for single-level cells. It is one of the older NAND Flash, with each cell representing only one binary digit (bit). SLCs, or single-level cells, hold one bit per cell. SLC offers the best endurance, but it is also the most expensive type of NAND flash storage.
Multi-Level Cell
MLC 或多电平单元每个单元存储两个比特，因此每个多电平单元可以容纳两个比特。这些单元的耐用性不如 SLC，因为写入周期和确保的频率是 SLC 的两倍。
MLC, or multi-level cells, store two bits per cell; hence each Multi-Level Cell may hold two bits. These cells have less endurance than SLCs since Write Cycles and ensure occur twice as frequently as SLCs.
Triple-Level Cell
TLC 表示三电平单元。顾名思义，每个单元包含三个比特的内存，从而可以在相同空间中存储更多的数据。TLC 驱动器主要由企业和消费者公司使用。
TLC stands for Triple-Level Cell. As the name implies, each cell contains three bits of memory, allowing for greater data storage in the same footprint. TLC drives are primarily used by enterprise and consumer companies.