SSDs and HDDs are different. Physically, SSDs and HDDs are similar, but they store data differently. How you use your computer will determine which sort of drive is best for you. Our HDD vs. SSD tutorial explains how each type of drive works.
What is a HDD?
Hard disk technology is well-tested. Hard drives have continually increased storage capacity and shrunk in size for more than 50 years. HDDs read and write data via spinning platters.
How hard disk drives (HDD) work
Hard disk drives consist of magnetically sensitive platters, actuator arms with read/write heads, and a motor to spin the platters and move the arms. A hardware I/O controller and firmware communicate with the rest of the system.
Each platter has tracks. Sectors are logical tracks. Each track and sector number creates a unique address for organizing and locating data. The nearest available area receives data. A pre-writing algorithm allows the firmware to detect and rectify problems.
Pre-set platter speeds (4200 rpm to 7200 rpm for consumer computers). Read/write speeds are related. Higher pre-set speed means faster hard drive read/write speeds.
Reading and writing
When you ask your computer to retrieve or update data, the I/O controller informs the actuator arm where it is, and the read/write head reads the charge in each address. If data is updated, the read/write head adjusts the track and sector charge.
Latency is the time it takes the platter to spin and the actuator arm to find the right track and sector.
Mechanical parts used to read and write data slow down HDDs because physically finding and retrieving data takes longer than electronically. Mishandled or dropped mechanical parts can skip or fail. This is a problem with laptops but not desktops. HDDs are bulkier and more energy-intensive than SSDs.
Benefits of a HDD
Hard disk drives are a proven technology and less expensive than solid state drives for the same storage. HDDs have more storage than SSDs.
What is an SSD?
Flash memory gives SSDs exceptional performance and endurance. Because your hard drive has moving elements like magnetic heads, spindles, and platters, it’s simple for things to go wrong and you to lose data. SSDs have no moving parts, so they’re robust, cool, and energy-efficient.
How solid state drives (SDDs) work
SSDs employ the same technology as huge USB devices. NAND, used in SSDs, is flash memory. Floating gate transistors store data as a charge (or absence of charge). The gates are organized in a block-based layout. Each grid row is a page, regardless of block size.
An SSD controller keeps track of data locations.
Reading and writing
SSDs complicate data updates. When a block is updated, all its data must be refreshed. The old block’s data is copied to a new block, then wiped and overwritten.
When you ask your computer to retrieve or update data, the SSD controller reads the charge status.
When the disk is idle, garbage collection erases the old block so it can be written to again.
TRIM tells the SSD to forego rewriting data when erasing blocks. Because blocks can only be rewritten a finite number of times, this reduces premature drive wear.
To prevent drive wear, an algorithm ensures that each block is read/written equally. This automatic technique is termed wear leveling.
Because read/write needs data movement, SSDs are overprovisioned with storage; some of the drive is not reported to the operating system and is not accessible to the user. This lets the drive transfer and delete objects without reducing storage space.
Benefits of an SSD
What makes a solid state drive better? Games, apps, and movies load more quickly thanks to SSDs. SSDs are lighter and better suited to tolerate movement and droppage because of the technology they employ. Solid state disks also consume less energy, which makes it possible for computers to run cooler.
The fact that SSDs are faster than HDDs is one of their main advantages. For instance, the Crucial P5, our fastest NVMe SSD, can read and write data at astounding rates of 3400 and 2000 MB/s, respectively. Even portable SSDs outperform HDDs in speed. The X8 is up to 100 times quicker than USB flash drives2 and up to 7.5 times faster than conventional hard drives2 with read speeds up to 1050MB/s1 and sizes up to 2TB.
Is an SSD a hard drive?
Simply put, an SSD differs from a hard drive. An SSD employs flash memory without any moving elements, which makes it faster than a hard drive because hard drives use magnetically sensitive platters that are rotated by a motor.