Hard drive

A hard disk drive (sometimes abbreviated as hard drive, HD, or HDD) is a non-volatile memory hardware device that permanently stores and retrieves data on a computer. A hard drive is a secondary storage device that consists of one or more platters to which data is written using a magnetic head, all inside of an air-sealed casing. Internal hard disks reside in a drive bay, connect to the motherboardusing an ATA, SCSI, or SATA cable, and are powered by a connection to the PSU (power supply unit). All computers have a hard drive installed in them, which is used to store files for the operating system, software programs, and a user's personal files. A computer cannot function without a hard drive installed, as it requires one to function properly.

Hard drive components

As can be seen 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 hard drive is a circuit board called the disk controller or interface board and is what allows the hard drive to communicate with the computer.

How is a hard drive connected to a computer?

An internal hard drive is connected to the computer using a data cable (IDE, SATA, or SCSI) that connects to the motherboard and a power cable that connects to the power supply.

· How to install a hard drive or SSD.

Where is the hard drive found in a computer?

All primary computer hard drives are found inside a computer case and are attached to the computer motherboard using an ATA, SCSI, or SATA cable. Hard drives are powered by a connection to the PSU (power supply unit).

·          What does the inside of a computer look like?

·          How to list files in a directory or folder on the computer.

What is stored on a hard drive?

A hard drive can be used to store any data, including pictures, music, videos, text documents, and any files created or downloaded. Also, hard drives store files for the operating system and software programs that run on the computer.

What are the sizes of hard 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 hard drive?

Data sent to and read from the hard drive is interpreted by the disk controller, which tells the hard drive what to do and how to move the components in the drive. 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 they have been 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 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 hard 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.

External and internal hard drives

Although most hard drives are internal, there are also stand-alone devices called external hard drives, which can backup data on computers and expand the available disk space. External drives are often stored in an enclosure that helps protect the drive and allows it to interface with the computer, usually over USB or eSATA. An excellent example of an external backup device that supports multiple hard drives is the Drobo.

External hard drives come in many shapes and sizes. Some are large, about the size of a book, while others are about the size of a large smartphone. External hard drives can be very useful since they usually offer more space than a jump drive and are still portable. The picture to the right is an example of a laptop hard disk drive enclosure from Adaptec. The user may install a laptop hard drive of any storage capacity into the enclosure and connect it via USB port to the computer.

· How to connect an external hard drive to a computer.

HDD being replaced by SSD

SSDs (solid-state drives) have started to replace HDDs (hard disk drives) because of the distinct performance advantages they have over HDD, including faster access times and lower latency. While SSDs is becoming more and more popular, HDDs continue to be used in many desktop computers largely due to the value per dollar that HDDs offer over SSDs. However, more and more laptops are beginning to utilize SSD over HDD, helping to improve the reliability and stability of laptops.

History of the hard drive

The first hard drive was introduced to the market by IBM on September 13, 1956. The hard drive was first used in the RAMAC 305 system, with a storage capacity of 5 MB and a cost of about $50,000 ($10,000 per megabyte). The hard drive was built-in to the computer and was not removable.

In 1963, IBM developed the first removable hard drive, having a 2.6 MB storage capacity.

The first hard drive to have a storage capacity of one gigabyte was also developed by IBM in 1980. It weighed 550-pounds and cost $40,000.

1983 marked the introduction of the first 3.5-inch size hard drive, developed by Rodime. It had a storage capacity of 10 MB.

Seagate was the first company to introduce a 7200 RPM hard drive in 1992. Seagate also introduced the first 10,000 RPM hard drive in 1996and the first 15,000 RPM hard drive in 2000.

The first SSD (solid-state drive) as we know them today was developed by SanDisk Corporation in 1991, with a storage capacity of 20 MB. However, this was not a flash-based SSD, which were introduced later in 1995 by M-Systems. These drives did not require a battery to keep data stored on the memory chips, making them a non-volatile storage medium.

  1. Computer hard drive history

Should I say "hard disk drive" or "hard drive"?

Both "hard disk drive" and "hard drive" are correct and mean the same thing. However, SSDs (solid-state drives) have no disks or platters, which is why we use and recommend using the term "hard drive" in your writing or when describing a hard drive.