自从第一个硬盘驱动器通过叉车(forklift)交付以来，机械驱动技术的基本原理没有太大变化。今天，现代硬盘驱动器的改进和创新比那些早期系统领先光年，尤其是在小型化方面。
CMR（传统磁记录）和SMR驱动器（叠瓦式磁记录）代表将这些微小数据位打包到HDD外壳中的两种不同方式。如果您了解每种方法的工作原理，就可以选择最符合您需求的驱动器类型。
机械(Mechanical Hard)硬盘的基础(Basics)知识
机械硬盘驱动器是使用涂有磁性材料的旋转磁盘（盘片）来存储数据的存储设备。这些硬盘驱动器使用读磁头和写磁头（悬停在盘片表面的小型机电臂）来访问和操作存储在磁盘上的数据。
将数据写入机械硬盘时，读/写头会磁化盘片表面的微小区域以表示数据。即使硬盘驱动器断电，这些磁化区域也会保持其电荷并可用于稍后检索数据。当硬盘驱动器通电时，盘片开始旋转，读/写磁头移动到盘片上的适当位置以访问数据。
CMR 对比 单核磁共振
机械硬盘有两种类型：CMR硬盘和SMR硬盘。
CMR技术使用单独的磁道将数据存储在磁盘上。每条磁道在盘片上都是一个同心圆，硬盘的读写头可以独立访问任意一个磁道。这允许快速读取和写入速度，因为磁头可以在磁道之间快速跳转以访问不同的数据。
(SMR)另一方面，SMR硬盘驱动器与磁盘上的磁道重叠，以实现大容量存储。这种重叠被称为“叠瓦”，因为它类似于屋顶瓦片的铺设方式。
要将数据写入SMR硬盘，磁头必须先擦除重叠磁道中的现有数据，这可能比写入CMR硬盘慢。此外，磁头必须按顺序移动通过磁道以访问数据，而不是能够在磁道之间跳转，这也会影响性能。
CMR 硬盘(CMR Hard)驱动器
的优点和缺点(Disadvantages)
这两种硬盘驱动器类型各有利弊。让我们先回顾一下CMR(CMR)驱动器
的优点和缺点：
- CMR硬盘驱动器允许读/写磁头在磁道之间快速跳转，与其他类型的硬盘驱动器相比，这可以提高传输速率。
- CMR硬盘驱动器非常适合需要快速数据访问的任务，例如游戏、视频编辑和数据传输。
- CMR硬盘驱动器随处可见，具有各种尺寸和存储容量。
- (Data)CMR驱动器上的(CMR)数据恢复通常比SMR驱动器更容易，因为 CMR 驱动器上的磁道不(CMR)重叠，因此可以独立读取每个磁道。
CMR驱动器的缺点如下：
- CMR驱动器通常具有较低的存储密度，这意味着它们无法在与SMR相同的物理空间中存储尽可能多的数据。
- 它们无法提供与SMR驱动器相同水平的成本效率，因为它们需要更多的物理空间来存储相同数量的数据。
- CMR驱动器可能不适合在有大量数据写入和重写的情况下使用，因为在这些情况下它们的性能可能不如SMR驱动器。
这些是概括，CMR或SMR驱动器的具体性能可能取决于多种因素，例如特定品牌（例如三星(Samsung)、东芝(Toshiba)、西部数据(Digital)或希捷(Seagate)）和型号（例如Ironwolf Pro、Red Plus、驱动器的Red Pro或Barracuda）及其用于的特定工作负载。因此，重要的是要参考各个驱动器的额定规格，而不是仅仅关注这一个因素。
SMR硬盘(SMR Hard)的优缺点(Disadvantages)_
SMR驱动器带来了它们自己独特的优势和权衡。SMR技术的最佳方面如下：
- SMR硬盘通常比相同大小的CMR硬盘具有更高的存储容量。这可以使它们成为需要大量存储空间的用户的不错选择，例如用于大型媒体收藏或备份目的。
- SMR硬盘驱动器通常比相同大小的CMR硬盘驱动器便宜，这使得它们对希望在预算内最大化存储空间的用户更具吸引力。
在得分表的消极方面：
- 要对SMR(SMR)硬盘进行写操作，写磁头必须先擦除重叠磁道中的现有数据。这可能比写入CMR硬盘驱动器慢，尤其是对于大文件。
- 磁头必须按顺序移动通过数据轨道才能访问SMR硬盘驱动器上的数据，而不是能够在轨道之间跳转。这可能会影响需要快速驱动器访问的任务的性能，例如游戏、视频编辑和数据传输。
- 某些系统（例如某些Linux 发行版）可能与(Linux distros)SMR硬盘不兼容，因此在购买SMR硬盘之前检查您的系统规格至关重要。
SMR硬盘对于需要大量存储空间并且愿意以较低的价格牺牲一些写入速度和性能的用户来说是一个不错的选择。这使得SMR磁盘成为归档大量数据的有吸引力的选择。
哪个更(Better)适合特定用(Specific Use)例：CMR 还是SMR？
很难对CMR或SMR硬盘驱动器哪个更好做出笼统的声明，因为它最终取决于您的特定用例和优先级。
(CMR)与SMR(SMR)硬盘相比， CMR硬盘通常提供更快的读写速度。这对于需要高性能的任务非常重要，例如游戏、视频编辑和数据传输。但是，性能差异对于其他任务可能微不足道，例如一般文件存储或日常计算。
就此而言，SSD（固态硬盘(Solid State Drives)）明显优于CMR磁盘。我们强烈建议每个人都使用SSD作为他们的主要操作系统和应用程序驱动器。这不仅是为了纯粹的性能，也是为了节能功耗，尤其是在磁盘需要保持旋转以快速响应的空闲时间。
SMR硬盘通常比相同大小的CMR硬盘具有更高的存储容量。这可以使它们成为需要大量存储空间的用户的不错选择，例如用于大型媒体收藏或备份目的。如果您正在寻找用于数据存储的外部硬盘驱动器，最好寻找SMR型号。
SMR硬盘驱动器通常比相同大小的(SMR)CMR硬盘驱动器便宜得多，这使得它们对希望在预算内最大化存储空间的用户更具吸引力。
第三名竞争者：PMR
PMR代表“垂直磁记录”。在PMR硬盘驱动器中，磁盘上的磁性粒子垂直于磁盘表面排列，而不是像旧技术那样平行排列。这允许更高的数据密度和更多的数据存储在磁盘上。PMR是当今硬盘驱动器中最常用的技术。
CMR与PMR类似，但磁盘上的磁性粒子层数较少。这导致存储密度低于PMR，并且通常允许更快的读取和写入速度。
换句话说，PMR驱动器就像(PMR)CMR和SMR驱动器之间的中间地带。当您不需要CMR的速度或(CMR)SMR驱动器的绝对存储，而是需要它们之间的最佳位置时，这使它们成为一个不错的选择。例如，PMR驱动器可能是家庭NAS服务器（网络附加存储(Network-attached Storage)）设置的不错选择，在这种情况下，Wi-Fi技术的限制意味着最终速度不是主要因素。
CMR vs. SMR Hard Drives: What’s Different and Which Is Better?
The fundamentals of mechanical drive tеchnology haven’t changed much since the first hard drive was delivered via forklift. Today, the refinement and innovation in modern hard drives are light years ahead of those early systems, especially regarding miniaturization.
CMR (conventional magnetic recording) and SMR drives (shingled magnetic recording) represent two different ways of packing those microscopic bits of data into an HDD enclosure. If you understand how each approach works, you can choose the type of drive that best matches your needs.
The Basics of Mechanical Hard Drives
Mechanical hard disk drives are storage devices that use spinning disks (platters) coated with a magnetic material to store data. These hard drives use read heads and write heads, which are small electromechanical arms that hover over the surface of the platters, to access and manipulate the data stored on the disks.
When data is written to a mechanical hard drive, the read/write head magnetizes tiny regions on the surface of the platters to represent the data. Even if the hard drive is powered off, these magnetized regions maintain their charge and can be used to retrieve the data later. As the hard drive is powered on, the platters start spinning, and the read/write head moves to the appropriate location on the platters to access the data.
CMR Vs. SMR
There are two types of mechanical hard drives: CMR hard drives and SMR hard drives.
CMR technology uses separate tracks to store data on the magnetic platter. Each track is a concentric circle on the platter, and the hard drive’s read/write head can access any track independently. This allows for fast read and write speeds, as the head can quickly jump between tracks to access different data.
SMR hard drives, on the other hand, overlap the tracks on the magnetic platter to allow for high-capacity storage. This overlap is known as “shingling” because it resembles how roof tiles are laid.
To write data to an SMR hard drive, the head must first erase the existing data in the overlapping track, which can be slower than writing to a CMR hard drive. Also, the head must move sequentially through the tracks to access data rather than being able to jump between tracks, which can also impact performance.
Advantages and Disadvantages of CMR Hard Drives
Both of these hard drive types offer their pros and cons. Let’s go over the strengths and weaknesses of CMR drives first:
- CMR hard drives allow the read/write head to quickly jump between tracks, which can improve transfer rates compared to other types of hard drives.
- CMR hard drives are well-suited for tasks requiring fast data access, such as gaming, video editing, and data transfer.
- CMR hard drives are widely available and can be found in various sizes and storage capacities.
- Data recovery is generally easier on a CMR drive than an SMR drive because the tracks on a CMR drive are not overlapped, so each track can be read independently.
The disadvantages of CMR drives are as follows:
- CMR drives generally have a lower storage density, which means they cannot store as much data in the same physical space as SMR.
- They don’t offer the same level of cost efficiency as SMR drives, as they require more physical space to store the same amount of data.
- CMR drives may not be as suitable for use in situations where there is a lot of writing and rewriting of data, as they may not perform as well as SMR drives in these situations.
These are generalizations, and the specific performance of a CMR or SMR drive can depend on a variety of factors, such as the specific make (e.g., Samsung, Toshiba, Western Digital or Seagate) and model (e.g., Ironwolf Pro, Red Plus, Red Pro, or Barracuda) of the drive and the specific workload it is being used for. So it’s important to refer to the rated specs of individual drives, rather than simply focusing on this one factor.
Advantages and Disadvantages of SMR Hard Drives
SMR drives bring their own unique sets of advantages and tradeoffs to the table. The best aspects of SMR technology are as follows:
- SMR hard drives typically have higher storage capacities than CMR hard drives of the same size. This can make them a good choice for users who need a lot of storage space, such as for large media collections or backup purposes.
- SMR hard drives are typically cheaper than CMR hard drives of the same size, making them more appealing for users looking to maximize their storage space on a budget.
On the negative side of the score sheet:
- To perform write operations on an SMR hard drive, the write head must first erase the existing data in the overlapping track. This can be slower than writing to a CMR hard drive, especially for large files.
- The head must move sequentially through the data tracks to access data on an SMR hard drive rather than being able to jump between tracks. This can impact performance for tasks that require fast drive access, such as gaming, video editing, and data transfer.
- Some systems (such as certain Linux distros) may not be compatible with SMR hard drives, so it’s essential to check your system’s specifications before purchasing an SMR hard drive.
SMR hard drives are a good choice for users who need a lot of storage space and are willing to trade off some write speed and performance for a lower price. This makes SMR disks an attractive option for archiving large amounts of data.
Which Is Better for Specific Use Cases: CMR or SMR?
It’s hard to make a blanket statement about whether CMR or SMR hard drives are better, as it ultimately depends on your specific use case and priorities.
CMR hard drives generally offer faster read and write speeds compared to SMR hard drives. This can be important for tasks that require high performance, such as gaming, video editing, and data transfer. However, the performance difference may be insignificant for other tasks, such as general file storage or everyday computing.
SSDs (Solid State Drives) are significantly better than CMR disks for that purpose. We strongly recommend that everyone use an SSD as their primary operating system and application drive. This is not only for pure performance but for energy-efficient power consumption, especially during idle times when disks need to keep spinning to respond quickly.
SMR hard drives typically have higher storage capacities than CMR hard drives of the same size. This can make them a good choice for users who need a lot of storage space, such as for large media collections or backup purposes. If you’re looking for an external hard drive for data storage, it’s probably best to look for an SMR model.
SMR hard drives are usually much cheaper than CMR hard drives of the same size, making them more appealing for users looking to maximize their storage space on a budget.
The Third Contender: PMR
PMR stands for “Perpendicular Magnetic Recording.” In a PMR hard drive, the magnetic particles on the disk are arranged perpendicular to the disk’s surface, rather than parallel to it as in older technologies. This allows for higher data density and more data to be stored on the disk. PMR is the most common technology used in hard drives today.
CMR is similar to PMR but with fewer layers of magnetic particles on the disk. This results in a lower storage density than PMR and typically allows for faster read and write speeds.
In other words, PMR drives are like the middle ground between CMR and SMR drives. This makes them a good choice when you don’t need the speed of a CMR or the absolute storage of an SMR drive, but rather the sweet spot between them. For example, PMR drives may be a good choice for a home NAS server (Network-attached Storage) setup where the limits of Wi-Fi technology mean ultimate speed isn’t a major factor.
