Articles: A primer on hard drive technologies
This scope of this article is to explain the differences in the different hard drive technology used in Apple computers, and how that might affect your choices when it comes to buying a Mac from us, whether new or used. While meant to be informative, this is far from an exhaustive look at the subject and is designed to build vocabulary and acumen around the subject with out having to become an expert.
While there have been many hard drive technologies used by Apple over the years, there are 3 storage media formats that are in use currently:
Hard Disk Drive
This technology has remained mostly unchanged since its introduction in 1956, aside from capacity and physical size. This type of drive is mechanical, and operates much like a record player. In mostly 3.5” and 2.5” sizes, a flat metal platter that holds a magnetic charge in thousands of tiny cells to represent the 1's & 0's of your data, and employs a magnetic “needle” to read and write the data. The hard disk drive has only just, in the last few years, begun to give market share to SSDs.
ATA, SATA, S-SATA, SCSI and ZIF interfaces have been used with this drive type in a variety of Macs.
Here's a great explanation as to how hard drives work from a Seagate Engineer.
Wikipedia also has a thorough description of hard disk drives.
Solid State Disk
Solid state disk drives have significant advantages over traditional magnetic storage drives. Having no moving parts, they offer fantastic performance and in many cases will outlast the computer in which they are installed. The term “solid state” was coined in the mid 1940’s and implies that the electrical signal travels through some type of solid semiconducting material, as opposed to the old vacuum tube components that were replaced by transistors. Today, this term implies that data is being writing in a purely electrical state to a constellation of memory chips. This is opposed to being translated into magnetism to change the state of a metal platter in a magnetic drive, in a SSD the “state” of the memory chip doesn't change, its electrical status is the only thing that changes. Apple now uses the term “Flash” storage to describe this type of disk, but you will see the term SSD in use in many marketing materials and in tech specs. There are many types of interfaces for this type of drive, such as SATA, MSATA, PCIe, GumStick, but the idea remains the same: fast, reliable storage.
Here's an entertaining video explanation of HDD vs. SSD.
Fusion Drive combines the spaciousness of a traditional hard drive with the high performance of flash storage. This type of storage is unique in that two drives are working together to try to achieve the best of both worlds: SSD-like performance with HDD capacity and price. Apple has created some very interesting technology to make this work, essentially tricking the operating system to think a fusion drive is a single drive, and intelligently moving files from one drive to the other (without user input) to make the computer more responsive and “fast” while still having thousands of gigabytes to save information.
There can be limitations to this type of storage, including software issues, inability to import long (3+hr) videos directly from a camera, and troubleshooting can sometimes be more difficult due to the unique software environment created by a Fusion Drive. Overall, for budget-minded customers who want the best performance per dollar, this is a great option, but pro users will want to look for pure Flash/SSD options to ensure optimal performance.
We hope these explanations help you in your understanding of storage technologies. If you have more questions, simply talk to one of the expert PowerMax consultants –if you have the questions, we'll have the answers!
By Ian Burnett, Certified Apple Technician