There are two different types of hard drives used in computers as data storage devices: hard disk drives (HDDs) and solid state drives (SSDs). Each uses different types of interfaces, such as Serial Advanced Technology Attachment (SATA), to store data and make it accessible to users.
Hard drives and solid state drives perform the same function, but they’re built differently. Hard drives use a stack of disks, called platters, that rotate inside your computer to store data, and solid state drives use interconnected flash-memory chips in place of any moving parts. While HDDs have slower processing times, the efficiency of SSDs comes with a price—SSDs are more expensive
HDDs are the old standard for computer memory devices, but typically have slower processing speeds than SSDs. Storage technology has evolved over time so that hard drives now have multiple storage capacities, form factors, and speeds to choose from.
- Storage capacity refers to the amount of data your storage device can hold.
- Form factor refers to the physical size of the device, like how thin and lightweight your device can be and how it impacts the size and weight of your computer.
- Speed refers to the performance of your storage device when booting, launching, and loading, and how it impacts the processing speed of your computer.
This post breaks down the different types of hard drives and walks you through which one might be the best choice for your storage needs.
The Evolution of Hard Drives
Hard drives have come a long way since the IBM Model 350 Disk File. Here’s a brief overview of some of the technologies that gave way to the hard drives we use today.
Small Computer System Interface (SCSI)
SCSI, pronounced “scuzzy,” was created in 1986 by the American National Standards Institute. It allows multiple devices to be “daisy-chained” together, including hard drives, printers, scanners, and more. The fastest SCSI interface (Ultra-640 SCSI) was 640 MBps and could connect 16 devices.
SCSI could be used to control a redundant array of independent discs (RAID). A RAID setup stores the same data in different places or on multiple hard disks. Incorporating backup disks provides some built-in protection against data loss.
SCSI is rarely used anymore, though it may still be used with enterprise servers. It’s mostly obsolete because the parts that make it functional, like connectors, are no longer manufactured. Serial attached SCSI (SAS) is now more commonly used.
Parallel Advanced Technology Attachment (PATA)
PATA, also known as Integrated Drive Electronics (IDE), was created in the 1980s by Western Digital. It was previously known as ATA, but became more commonly known as PATA or parallel ATA once the Serial Advanced Technology Attachment (SATA) was invented.
PATA hard drives use the PATA attachment and cable to connect one or two hard drives to the computer motherboard. The cable has three connections: one to connect to the motherboard and two that could connect to drives. It also had a large 40-pin ribbon connector with up to 80 wires.
PATA drives transfer data in parallel, meaning that multiple bits of data are transferred simultaneously. Certain issues can arise with this mechanism. For example, signals from multiple data lines can arrive at different times to the receiving ends, making them out of sync. Parallel data channels are also prone to electromagnetic interference between wires.
There were many versions of PATA and speeds continued to increase as the attachment evolved. It was widely used until Serial ATA (SATA) was introduced in 2003.
The Most Common Types of Hard Drives
The following sections detail the most common types of hard drives as well as their pros and cons so you can make an informed decision about which one should work best for you.
Serial Advanced Technology Attachment (SATA HDD)
SATA, the upgrade from PATA, was introduced in 2003. Much faster and more compact than its predecessor, it uses thin and flexible wires to transfer data, achieving rates of 600 MB/s or less, with storage capacities of up to 16 TB.
SATA drives use a 7-PIN data connection, and there is only one disk drive per SATA controller chip on the motherboard. There are multiple generations (SATA 1.0, 2.0, 3.0, and so on), though, in recent years, SATA HDDs are less common in laptops, as most manufacturers have switched to SSDs. They’re still used in desktops.
Both HDDs and SSDs can have SATA interfaces, but when people refer to a SATA hard drive they’re typically talking about a SATA interface used with an HDD.
Pros:
- High storage capacity
- Low cost
- Forward and backward compatible
Cons:
- May need additional components if you’re using them with older systems
- Slower and less bandwidth than NVMe
- Requires an individual cable for each drive connection
Serial Attached Small Computer System Interface (SAS)
SAS hard drives are meant for use in servers or process-heavy computer environments. They’re primarily used for small businesses or those that require servers and workstations rather than regular desktop computers.
Its wires are divided between two cables, allowing you to connect more devices. It uses serial data transfer, sending data over a communication sequentially, one bit at a time. SAS is fast in transferring data in and out of storage and fast at reading and writing data continuously.
Pros:
- Fast data transfer
- Useful for servers or workstations
- Allows for multiple connections
Cons:
- Uses a lot of power to operate
- Less storage capacity
Serial Advanced Technology Attachment Solid State Drive (SATA SSD)
When you hear about SSD as a type of hard drive, the SATA SSD is typically what people are referring to. A type of solid state drive, it uses the SATA hardware interface and protocol to transfer and store data.
SSDs are generally significantly more expensive than HDD options, but come with multiple advantages, like larger storage capacities, faster speeds, and typically more compact sizes, making them ideal for laptops. The largest SSD on the market is 100 TB, though 2 TB or less are more common consumer options. Data transfer rates are much faster than HDDs, with speeds of about 500 MB/s in SSDs vs. 30 to 150 MB/s in HDDs.
SATA SSDs have multiple form factors, including 2.5” and M.2., and can easily be added as an upgrade to SATA HDDs.
Pros:
- High data-processing speeds and file copying/transferring when compared to HDDs
- Durable
- Come in small sizes
- Quiet
Cons:
- Expensive
- Less storage capacity than HDDs
Non-Volatile Memory Express Solid State Drive (NVMe SSD)
NVMe is a storage access and transport protocol for SSDs. It was introduced in 2011, and uses PCIe as its standard interface. The technology uses multiple lanes and transfers data at rates of up to 64,000 MB/s, making it significantly faster than SATA SSD. NVMe drives are useful for video editing and large file transfers.
In addition to offering faster processing speeds, NVMe technology also has lower latency than SATA, due to its use of shortened and optimized data pathways. It manages queues more efficiently, greatly reducing CPU overhead. SATA is still, however, a more efficient option over traditional HDDs, and is more commonly found in devices than NVMe.
Pros:
- Transfers more information faster compared to other storage devices because it has a higher input/output system
- Considered the new industry standard for gaming consoles and high-end computers
Cons:
- More expensive
- Not a lot of support for older computer operating systems
- Uses a lot of power
Which Type of Hard Drive Do I Need?
No matter which you choose, there are pros and cons to each type of drive. Choosing the right hard drive comes down to its compatibility with your device and your needs for storage and speed, since each type of hard drive has different specs.
- SATA HDD: Best for desktops performing basic computing tasks.
- SAS HDD: Best for workstations and servers, rarely for personal use.
- SATA SSD: Best for computers where high storage capacity at an affordable price is required.
- NVMe SSD: Best for computers where high transfer speeds and bandwidth are required. For example, when gaming or extensive photo/video work.
Data Recovery for Your Hard Drive
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