What is a hard drive?
It’s a common question and one that we’re more than happy to answer. Whether you are looking for ways to upgrade your hard drive, trying to buy a computer with the right hard drive, or just trying to figure out what everyone is talking about, read on. We’ll explain everything and give you tips on which hard drive properties are essential.
The Purpose of hard Drives
The hard drive is where a computing device stores data for the long term — not just the things you save. But all the code required for the operating system, the framework browsers use to access the internet, drivers for accessories, and everything else. When referring to computer storage, drive” (or solid-state drive, see below) is typically used.
Every hard drive has a specific amount of space. Some of that space is automatically consumed by the OS and backup installations. However, the rest can be filled with data you download and save. Whether it’s a new app or a funny cat picture someone shared.
Hard drive space isn’t as important now as it once was. That’s because cloud-based software doesn’t require local storage. Data can be stored in the cloud as well, freeing up precious space on the drive.
This cloud-based dependency — which relies on remote servers and their hard drives in data centers — originally fueled Google’s Chrome OS platform. Chromebooks have very little physical storage space due to their reliance on streaming and cloud solutions. That’s changing to some degree, thanks to growing support for Google Play Android apps.
Birth of the hard drive
Reynold B. Johnson developed the first real hard drive at IBM in 1956. Johnson’s team originally experimented with other methods to store data on things like magnetic tape.
However, his team discovered ways to store information (in the form of bytes) on metal, magnetic disks, which could overwrite with new information as desired. This led to the development of an automated disk that reads itself like a record player — except much larger. The first commercially available version, RAMAC, had a hard drive nearly the size of a kitchen pantry.
Later, IBM developed floppy disks in the late 1960s to easily load code into their mainframes. These disks initially measured 8 inches in diameter, packing read-only data. The first commercially available read/write drive didn’t appear until 1972 when the team’s head — Alan Shugart — migrated to Memorex.
Overall, these two parts — the automated magnetic disk and the smaller, transferable “floppy” disk — became the backbone of the early hard drive. For many years, the method of storing data remained the same, while great improvements were made in how the hard drive could store, read, and eventually write data on the disk.
Can a computer work without a hard drive?
Without a hard drive, a computer can turn on and POST. Depending on how the BIOS is configured, other bootable devices in the boot sequence are also check for the necessary boot files. For example, if the USB device is being listed in your BIOS boot sequence, you can boot from a bootable USB flash drive in a computer without a drive.
Examples of bootable flash drives include a Microsoft Windows installation disk, GParted Live, Ubuntu Live, or UBCD. Some computers also support booting over a network with a PXE (preboot execution environment).
Two types of Hard drives
- Internal
- External
Internal means a hard drive is located inside a computing device and directly connects to the motherboard, but it’s not always upgradable. For instance, a desktop side can be easily removed to disconnect the old drive and connect the new drive. It’s a quick, simple upgrade.
On laptops, however, the upgrade process may not be quite so simple. Typically there is a door along the bottom providing access to the drive. Other laptops, like Apple’s MacBooks, don’t have removable storage. Read the specifications on the manufacturer’s websites on how to change a laptop’s drive properly.
External means a hard drive is located outside the PC and typically connects through a USB or Thunderbolt cable. This option is typically slower due to the connection, but it can also be detached from the parent PC without any major issues.
Besides internal and external, a hard drive can be a hard disk drive (HDD) or a solid-state drive (SSD). There’s a huge difference between the two that we explain in a separate article, SSD versus HDD. However, here are the shorter explanations:
HDD: Hard drive disks use a spinning magnetic disk that holds information inscribed in very tiny tracks — a bit like a record player. This requires moving parts, specifically heads to read and write data to the disk as needed and propulsion to spin the disk. It’s a simple method, making HDDs very inexpensive to purchase, especially when creating extensive storage setups.
SSD: There are no moving parts in SSDs. Instead, these drives use semiconductors that store information by changing the electrical state of very tiny capacitors. They are much faster than HDDs and can store information more easily without the risk of parts wearing out. SSDs are why modern PCs boot up so fast.
Important hard drive qualities
- Speed
- Physical security
- Connections
Speed: The speed of a hard drive depends on how fast it can read or write data. The connection to the PC also factors in. A poor connection can bottleneck the data flow and, ultimately, impact the machine’s performance. For mechanical hard drives, the spin speed is also essential: 7,200RPM drives, for example, are faster than 5,400RPM drives. Both are far slower than SSDs.
Physical security: Hard drives need to be able to resist the occasional jolts and bumps. That’s what physical security is all about — your device’s resistance to damage that could result in data loss. Physical security is primarily about durability, and it’s an important consideration for both internally mounted and external drives.
Environmental factors, such as extreme heat or cold, are an essential consideration. Also, some manufacturers include features that help prevent hacking or discourage theft.
Connections: Choose a hard drive with ports that fit your computer, like PCI Express, Thunderbolt, USB, or SATA. Check out our guide to learn more about SATA. Make sure you know your computer connection types.
Different hard drives affect speed differently. An external solid-state drive connected to an old port will significantly restrict data flow by 60 megabytes per second.
Know your available connections and choose the best option to work with the hardware you currently have.
Hard drive components
As shown in the picture above, the desktop hard drive consists of the following components: the head actuator, read/write actuator arm, read/write head, spindle, and platter. On the back of a drive is a circuit board called the disk controller or interface board. This circuit is what allows the drive to communicate with the computer.
How is a hard drive connected to a computer?
An internal hard drive connects to the computer using two means: a data cable (IDE, SATA, or SCSI) to the motherboard and a power cable to the power supply
What is stored on a hard drive?
A hard drive can store any data, including pictures, music, videos, text documents, and any files created or downloaded. Also, drives store files for the operating system and software programs that run on the computer.
What are the sizes of the drives?
The hard drive is often capable of storing more data than any other drive, but its size can vary depending on the type of drive and its age. Older hard drives had a storage size of several hundred MB (megabytes) to several GB (gigabytes). Newer hard drives have a storage size of several hundred gigabytes to several TB (terabytes). Each year, new and improved technology allows for increasing hard drive storage sizes.
How is data read and stored on a drive?
Data sent to and read from the hard drive is interpreted by the disk controller. This device tells the hard drive what to do and how to move its components. When the operating system needs to read or write information, it examines the hard drive’s FAT (File Allocation Table) to determine file location and available write areas. Once that is determined, the disk controller instructs the actuator to move the read/write arm and align the read/write head. Because files are often scattered throughout the platter, the head needs to move to different locations to access all information.
All information saved and stored on a traditional hard drive, like the above example, is done magnetically. After completing the above steps, if the computer needs to read information from the drive, it would read the magnetic polarities on the platter. One side of the magnetic polarity is 0, and the other is 1. Reading this as binary data, the computer can understand what the data is on the platter. For the computer to write information to the platter, the read/write head aligns the magnetic polarities, writing 0’s and 1’s that can be read later.
Finally, we talked about hard drives and kinds of that So we hope you enjoy of reading that.