This blog post is article four in an educational series designed to give our readers an opportunity to learn more about how computers function without getting burdened with highly technical details. Last month, we discussed the GPU. Today, we will be exploring storage drives.

Permanence of data is an aspect, and indeed, a privilege, of computing that many consumers do not fully appreciate. The ability to write a Word document on Monday and return to edit it on Wednesday, even after shutting off the computer, is an example of this critical capability, and permanent storage drives are the components that enable this functionality.

There are many forms of storage media commonly deployed in the consumer computing market space, but they all serve a common function; storage drives allow data to be written to and read from their information stores by the computer’s operating system and, by extension, the user. Documents, photos, videos, system files, and all forms of data that are not being actively modified by the system exist in some form of storage for access in the future. Because of widespread deployment and integrating into the popular lingo, the hard drive (HDD) is the most common, well known form of storage drive. Without getting too deep into the mechanics of it, a HDD consists of several spinning disks (called “platters”) with a needle-like head that can both etch data into the disk as bits of information or read back previously written bits. HDDs exist in both desktop and laptop form factors. Recently, solid-state drives, or SSDs, have taken the storage market by storm with an entirely different system of recording and accessing data. SSDs use transistors, like RAM does, but unlike RAM, SSD NAND is “non-volatile.” In other words, SSDs can preserve their data even when power is removed from the drive, a function HDDs and SSDs do not share with RAM. Because and SSD has no moving parts (like a flash drive, which uses similar technology), they can access data much faster than a mechanical hard disk, which needs to spin up to the correct location on the disk where the requested data is located. SSDs offer better performance and resistance to motion damage, but they cost a higher price per unit of data storage capacity. Predating both SSDs and HDDs were tape drives, which, like tape cassettes, record information on a film. While considerably older than newer standards of data storage, tape drives, due to their low cost, high capacity, and impressive long term reliability, continue to be used in large data centers or other enterprise markets, though they are a rare find for the average consumer nowadays. There are many manufacturers of modern storage drives, with Western Digital and Seagate being big names for HDDs and Samsung, PNY, and SanDisk being popular SSD manufacturers.

As there are several forms of storage drives, there are also several connection standards used to ensure efficient access to these devices. The most common connector is Serial ATA (called SATA), which consists of L-shaped data and power connectors. There are two forms of SATA (II and III), which refers to the data transfer speed. SATA Express was also temporarily explored as a standard connector for high speed drives but was never generally adopted by drive manufactures despite being present on many modern motherboards. Other drives, such as Intel’s 750 series SSDs, connect over the PCI Express interface like a graphics card does. This connection allows for high bandwidth than SATA can, preventing the connection from being throttled by a fully saturated data channel. A more efficient form of this interface is M.2, which offers the benefits of PCI Express lanes without the bulk of the x16 connector.

As we commonly do in this series, we will now explore the numbers used to describe this technology. The two main areas of measurement for storage drives are capacity and speed. Capacity is measured in Gigabytes (GBs) or Terabytes (TBs). HDDs are typically offered in 1-6 TB configurations, and SSDs are commonly purchased in 120GB-1TB capacities. Speed is typically measured in Gigabytes per second (GB/s), and there are different speeds associated with reading from and writing to the storage drive. SATA II drives can transfer up to 3GB/s and SATA III drives can achieve 6GB/s. PCI-E and M.2 drives can move data much faster, but the connection type does not determine the actual speed of the drive. Protocols like AHCI (an older standard for HDDs) and NVME (a newer standard for SSDs) also govern the real world performance of drives.

To summarize, storage drives allow us to permanently store data even without active power being supplied to the computer. They are typically divided between mechanical hard drives and newer solid state drives. SSDs are faster but more expensive per GB, whereas HDDs can offer high capacities for cheaper. There are many manufactures of drives as well as several different connection standards and speed ratings.

If you are interested in upgrading your storage drives, or if you suspect that they may be failing to function properly, feel free to bring your computer to one of Geek ABC’s drop off locations, give us a call, or email us at! Our technicians are more than happy to address whatever issues your computer might be facing. Thanks for reading, and be sure to check out our other blog posts! We hope to see you back for next month’s installment in “How Does My Computer Work?”.


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