Disk drive in the context of Loop recording

A digital video recorder (DVR), also referred to as a personal video recorder (PVR) particularly in Canadian and British English, is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device. The term includes set-top boxes (STB) with direct to disk recording, portable media players and TV gateways with recording capability, and digital camcorders. Personal computers can be connected to video capture devices and used as DVRs; in such cases the application software used to record video is an integral part of the DVR. Many DVRs are classified as consumer electronic devices. Similar small devices with built-in (~5 inch diagonal) displays and SSD support may be used for professional film or video production, as these recorders often do not have the limitations that built-in recorders in cameras have, offering wider codec support, the removal of recording time limitations and higher bitrates.

In computing, an optical disc drive (ODD) is a disc drive that uses laser light or electromagnetic waves within or near the visible light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can only read from certain discs, while other drives can both read and record. Those drives are called burners or writers since they physically burn the data onto the discs. Compact discs, DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by such drives.

Although most laptop manufacturers no longer have optical drives bundled with their products, external drives are still available for purchase separately.

In computing, a removable media is a data storage media that is designed to be readily inserted and removed from a system. Most early removable media, such as floppy disks and optical discs, require a dedicated read/write device (i.e. a drive) to be installed in the computer, while others, such as USB flash drives, are plug-and-play with all the hardware required to read them built into the device, so only need a driver software to be installed in order to communicate with the device. Some removable media readers/drives are integrated into the computer case, while others are standalone devices that need to be additionally installed or connected.

Examples of removable media that require a dedicated reader drive include:

A disk read-and-write head is the small part of a disk drive that moves above the disk platter and transforms the platter's magnetic field into electric current (reads the disk) or, vice versa, transforms electric current into magnetic field (writes the disk). The heads have gone through a number of changes over the years.

In a hard drive, the heads fly above the disk surface with clearance of as little as 3 nanometres. The flying height has been decreasing with each new generation of technology to enable higher areal density. The flying height of the head is controlled by the design of an air bearing etched onto the disk-facing surface of the slider. The role of the air bearing is to maintain a constant flying height as the head moves over the surface of the disk. The air bearings are carefully designed to maintain the same height across the entire platter, despite differing speeds depending on the head distance from the center of the platter. If the head hits the disk's surface, a catastrophic head crash can result. The heads often have a diamond-like carbon coating.