Hard Drives

Use this page to answer the questions on your Hard Drive worksheet. You will also need to look at your actual hard drive to answer some of the questions. Here are some common acronyms you should know:

HDD (hard disk drive) that uses a magnetic disk.

How does a hard drive work?

What do hard drives do? They store almost all the data for your computer. This can include the OS (operating system), software and apps, files, images, videos, etc.

Inside the drive is a disk platter that spins really fast. While the disk platter looks like a mirror, it is actually composed of up to trillions of tiny magnets that remember the 1's and 0's of your digital files. As you save files to the disk, the data is written as 0's and 1's in tiny areas of magnetic North or South on the platter.

In addition to the platter and the read/write head, each drive has controller circuitry, as well as an interface to connect with.

SSD and NVMe drives use flash memory instead of a magnetic disk. Flash memory uses floating gate transistors (FGTs) to store data. Each FGT contains a single bit of data, designated either as a 1 for a charged cell or a 0 if the cell has no electrical charge.

Hard drive sizes

HDD's and SSD's come in two basic physical sizes: 2.5-inch and 3.5-inch. These sizes refer to the size of the data platters, not the size of the hard drive mechanism. Traditionally, 2.5-inch drives are used for laptops while 3.5-inch drives are used for desktop computers. Some compact desktops also use the smaller drives to enable a smaller form factor for the computer.

NVMe drives are smaller, and are closer in size to a stick of RAM.

Hard drive capacity

The capacity of a hard drive is the amount of data it can hold. These days, capacity is measured in gigabytes (GB) or terabytes (TB).

When buying a new HDD it is better to get the largest capacity you are likely to need for the next few years so you have room for new files and programs. Running fewer drives saves on space, power draw and heat generation. It is also easier to manage your drives if there are fewer of them.

If you have several smaller capacity drives, it's probably time to think about combining the contents onto a single larger drive. Any 3.5 inch drives that are 250GB or less in capacity are probably getting old enough to be retired anyway.

Hard drive rotation speeds - mechanical HDD's only

As part of its specifications, each hard drive lists a rotation speed, measured in RPMs. The faster the drive, the faster it can read and write data. Since reading and writing to disk is often a computing bottleneck, this can be an easy place to speed things up in your workflow.

2.5-inch consumer drives spin at 4200, 5400, and 7200 RPMs. If you are using a laptop as a digital imaging computer, you will want the internal drive spin at 7200RPMs. Downloading files, working with Lightroom, opening in Photoshop, saving in Photoshop will all be faster with a faster drive. Slower drives can be fine as a laptop backup drive, since the speed here is generally less critical. 

3.5-inch drives generally come in 5400,  7200, 10,000, and 15,000 RPM models. 7200 RPM models are good all-purpose drives for working files. The slower drives can be a good choice for archive storage if you do not need to access the files a lot. The slower drives also generally use less electrical power and generate less heat.

ATA/IDE

SATA

PCIe (NVMe drives)

Hard Drive Interfaces

Hard drives come with one of several different connectors built in. When you buy a drive, it will specify which one is built into the drive. The most typical are SATA and PCIe. SATA has been the standard since about 2007, and newer drives are starting to use the PCI-e connector. ATA/IDE are now considered obsolete. Almost all computers now use some form of SATA connection.

ATA/IDE

For many years, Advanced Technology Attachment (ATA) connections were the favored internal drive connection in PCs. Apple adopted ATA with the Blue and White G3 models. ATA drives must be configured as either a master or a slave when connecting. This is usually accomplished by the use of a hardware jumper or, more recently, through the use of a cable that can tell the drive to act as either a master or slave.

ATA also goes by the name ATAPI, IDE, EIDE, and now, PATA, which stands for Parallel ATA. ATA connections aren't really used on hard drives anymore.

SATA

As of 2007, most new computers (Macs and PCs, laptops and desktops) use the newer SATA interface. It has a number of advantages, including longer cables, faster throughput, multi-drive support through port multiplier technology, and easier configuration. SATA drives can also be used with eSATA hardware (discussed later) to enable fast, inexpensive configuration as an external drive. Computers now come with drives that only have SATA connections.

PCIe

To help deliver a high-bandwidth, low-latency user experience, the NVMe protocol accesses flash storage via a PCI Express (PCIe) bus, which supports tens of thousands of parallel command queues and thus is much faster than hard disks and traditional all-flash architectures, which are limited to a single command queue.

Solid state drives

In a SSD instead of spinning disks, flash memory is being used as primary storage. Your phones memory card is flash memory storage. This type of device, called a solid-state drive (SSD), offers some important advantages, including extra speed, shock resistance, greatly reduced power draw and potentially greater reliability since they have no moving parts.

SSD drives don’t rely on moving parts or spinning disks. Instead, data is saved to a pool of NAND flash. NAND itself is made up of what are called floating gate transistors. NAND flash is designed to retain its charge state even when not powered up.

NVMe drives

NVMe (nonvolatile memory express) is a new storage access and transport protocol for flash and next-generation solid-state drives (SSDs) that delivers the highest throughput and fastest response times yet for all types of enterprise workloads. These drives plug directly into the motherboard and do not need data cables.

Unlike protocols designed in the days of mechanical hard disk drives, NVMe leverages not just solid-state storage, but also today’s multicore CPUs and gigabytes of memory.

Currently, the maximum speed for an NVMe PCIe 3.0 (aka Gen 3) SSD is up to 3,500MB per second, while a NVMe PCIe 4.0 (aka Gen 4) SSD can hit up to 7,500MB per second.

Running Multiple Hard Drives

Because modern drives use SATA interfaces they are hot swappable and it's very easy to add additional drives to your computer. Hot swappable means you can disconnect and reconnect a device while the computer is on. NOTE: you obviously can't disconnect the hard drive that runs your OS while the OS is running!

For example, you could have a fast SSD or NVMe drive that runs your OS and other software, and a slower but larger drive that you use for storage. You could then have that storage drive backed up to a cloud storage service, or another type of backup.

You'll notice each hard drive on your computer has a letter. The default letter for a single drive is (C:). If you had a CD/DVD drive installed it would show up as (D:). Any time you add a new drive it will show up as the next available letter in the alphabet. Even removable drives such as small flash drives or cameras are assigned the next available letter.

Signs of a Dying Hard Drive

1. Slowing Down Computer, Frequent Freezes, Blue Screen Of Death - These are very unspecific signs that can be caused by a million different things. However, regardless of what the issue behind these symptoms is, it is recommended that you immediately make a backup. If these problems occur after a fresh installations or in Windows Safe Mode, it is almost certain that it is due to bad hardware, and possibly a failing hard drive. 

2. Corrupted Data - If you’re beginning to find files that fail to open or if it contains corrupted data, even though the file saved without errors, or if files suddenly disappear, you should get worried.

3. Accumulation of Bad Sectors - Bad sectors are areas of the hard drive that do not maintain data integrity. They are automatically masked by the operating system and thus hard to identify, especially if large amounts of the disk are currently in use. If you actually run into bad sectors, however, that certainly is a bad sign.

4. Strange Sounds - When you hear strange noises coming from your hard drive, it may be too late already. A repetitive sound also known as the click of death is caused by the head as it is trying to write data and recovers from errors in doing so. Grinding or screeching noises indicate that parts of the hardware, for example the bearings or spindle motor, are failing. This only happens on HDDs.

5. Crashing on start-up - If you have to reboot your computer more than once to get it to start up, then this is a sign your SSD could be failing. The probable cause is a buildup of bad sectors that affects the files your computer needs during startup.

6. Slow saves - One of the strongest signs of the existence of bad sectors or bad blocks on your drive is a long delay in saving files. Bad blocks are sectors of the drive that have suffered physical or logical damage and can no longer be accessed.

If you suspect a hard drive is failing you should back up your files to an external drive or a come type of cloud storage such Google Drive or Microsoft OneDrive.

If a drive does completely fail, you can sometimes retrieve the data from it using software like Mini Tool or Disk Drill.

Checking for Hard Drive Failures