IT hardware can be complicated, and some of the differences between types of storage hardware are more subtle. In this article, we’ll be reviewing the difference between a hard drive vs SSD vs storage system. Lets get started!
What is a hard drive?
A hard drive is a spinning disk that utilizes magnetism to store binary information on “platters” coated in palladium. These platters contain countless micro grooves, and each of these grooves can represent a “bit,” where a magnetized groove represents a 1, or positive, and a non-magnetized groove represents a 0, or negative.
By stringing several of these “bits” together, binary information can be stored. For example 100011 would be “35.”
To organize the bits of data and ensure accuracy, they’re stored in orderly circular rows called “tracks”, much like a record player. These tracks are then organized together into “sectors.” To easily find the right locations to read or write to, part of the hard drive stores a map of which sectors are used already.
To read and write data, an arm moves a miniscule magnet known as a “read-write head” over the palladium platter as it rotates rapidly over a central spindle.
The read-write head’s own electromagnetism allows it to verify the status of each bit it passes over, and also pass a magnetic field over a bit to change its polarity. This changing of polarity is how the head “writes” data.
The circuit board on the bottom side of the hard drive facilitates the digital side of things, allowing communication of data to and from the platter(s).
The biggest take away here is that a hard drive spins.
What is an SSD?
SSDs, or Solid State Drives, offer the same functionality to store bulk data that hard drives do. The drives are shaped to the same laptop HDD 2.5″ form factor and offer comparable amounts of storage. The difference between SSDs and HDDs is in the technology that stores and writes the data. Rather than HDD’s mechanical spinning platters, SSDs use semiconductor chips.
An SSD contains transistor cells in a lattice of rows and columns. In SSDs, the cells are the intersection points with two transistors. One of them is a “control gate,” and the other is a “floating gate.”
When current is sent through to the control gate, electrons flow into the floating gate transistor. When the floating gate transistor becomes charged, it begins to block the flow of current through the transistor. If a transistor cell conducts current, it’s a “1,” in binary terms. If not, a “0.”
You can imagine the SSD’s binary storage system as a grid of lightbulbs. Each lightbulb is either “on” (1) or “off” (0) and represents binary data. The state of the bulbs can be read, giving a binary pattern that translates to information like numbers, text, code, pictures, video etc.
Unlike hard drives, SSDs do not spin and therefore have better reliability and resistance to failure.
What is the difference between HDD’s and SSD’s?
HDD’s are more vulnerable to mechanical failure since they contain moving parts. Enterprise hard drives last longer under heavier load but they will still fail. Usually they will warn the user before failure as they start to make a lot of noise or load data slowly.
Solid state drives do not suffer from mechanical problems, as they do not have moving parts. However, the electrical circuits that contain the data can wear out and fail. Writing data is harder on the drive than reading data.
One unique issue that SSDs have that hard drives don’t is electron wear. When writing a 1 or a 0 to the same location repeatedly, that cell can begin to wear out. This is mitigated through a concept called wear leveling or provisioning. Normally, an SSD fills up to 60 % and that data doesn’t change much, but the remaining 40% changes often as the user creates and deletes files. Once a failure occurs in that overused 40%, the whole drive fails. The provisioning function, reorganizes the information on the drive as needed. That way all sectors are being worked evenly, prolonging the life of the drive.
Hard drives have to spin to find and read data. A hard drive holds its data like a ferris wheel holds people. To get a particular person, you have to wait until the wheel spins around before they can get off. In the same way, you have to wait for a drive to finish spinning before you can retrieve your data. To speed them up engineers put stronger motors in the drives. A hard drive’s speed is measured in RPM, how fast the platters spin. Drives usually come in 5400 RPM and 7200 RPM for consumer varieties. And 10,000 RPM and 15,000 RPM for performance drives.
Solid State drives on the other hand are significantly faster than even the fastest hard drive. An SSD however, holds data like a bookshelf holds books. To get a particular book, you go right to the specific spot the book is located and retrieve it. Thus, the wait time is very minimal to retrieve data. There is no mechanical delay, the drive can access data at the speed of electricity. A windows 10 computer may take a few minutes to boot on a hard disk drive, but that same boot could be done in seconds by a solid state drive.
Cost. Hard drives cost less for the same amount of total storage. A 500GB hard drive costs about $20.00 as of May 2018, that same capacity costs about $120 for a solid state drive. Sometimes it can be cost effective to put the operating system and performance sensitive files on a small 128GB solid state drive; while long term files can be stored on a separate cheaper hard disk drive.
What is a storage system and where does it fit in?
Storage systems are specialized file servers that contain several of the aforementioned drives, either hard drives or SSDs. The system’s drives are typically arranged in a “RAID” configuration, or Redundant Array of Independent Disks. This configuration allows for improved performance and better system fault tolerance i.e. lower risk of data loss. Storage is classified as either NAS or SAN. Both are used to provide large scale network level shared storage.
The important take away here is a storage system isn’t a storage device, but rather a computer system with multiple storage drives attached used to manage large amounts of data.
What does a hard drives vs ssd vs storage system have in common?
The most obvious thing that all three of these things have in common is they are intended to store digital data to be accessed on a computer system. If your hard drives store any form of sensitive data, then effective hard drive wiping or erasure is something you need to consider, regardless of how large your storage is.
Hard Drive vs SSD vs Storage System Recap
We’ve now compared a hard drive vs SSD vs storage system and know where they all fit in in an IT environment. Each one has their own pros and cons and knowing this will help you pick the right tool for the job. If you are looking to sell your storage equipment, please check out sell your hard drives, sell your SSDs, and sell your storage system pages right here on Exit Technologies.
Have something to add? Let us know your thoughts in the comments below!