Computer data storage or digital data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers.
Disk storage is a data storage mechanism based on a rotating disk. The recording employs various electronic, magnetic, optical, or mechanical changes to the disk's surface layer. A disk drive is a device implementing such a storage mechanism. Notable types are hard disk drives (HDD), containing one or more non-removable rigid platters; the floppy disk drive (FDD) and its removable floppy disk; and various optical disc drives (ODD) and associated optical disc media.
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box.
Western Digital Corporation is an American data storage company headquartered in San Jose, California. It has a decades-long history in the electronics industry as an integrated circuit and data memory technology developer. It is one of the world's largest computer hard disk drive (HDD) manufacturers, along with producing solid-state drives (SSDs) and flash memory devices.
CompactFlash (CF) is a flash memory mass storage device used mainly in portable electronic devices. The format was specified and the devices were first manufactured by SanDisk in 1994.
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 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.
In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. In general, the term "mass" in "mass storage" is used to mean "large" in relation to contemporaneous hard disk drives, but it has also been used to mean "large" relative to the size of primary memory as for example with floppy disks on personal computers.
IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. The basic mechanical arrangement of hard disk drives has not changed since the IBM 1301. Disk drive performance and characteristics are measured by the same standards now as they were in the 1950s. Few products in history have enjoyed such spectacular declines in cost and physical size along with equally dramatic improvements in capacity and performance.
A disk enclosure is a specialized casing designed to hold and power hard disk drives or solid state drives while providing a mechanism to allow them to communicate to one or more separate computers.
Magnetic storage or magnetic recording is the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetisation in a magnetizable material to store data and is a form of non-volatile memory. The information is accessed using one or more read/write heads.
Density is a measure of the quantity of information bits that can be stored on a given physical space of a computer storage medium. There are three types of density: length of track, area of the surface, or in a given volume.
Millipede memory is a form of non-volatile computer memory. It promised a data density of more than 1 terabit per square inch, which is about the limit of the perpendicular recording hard drives. Millipede storage technology was pursued as a potential replacement for magnetic recording in hard drives and a means of reducing the physical size of the technology to that of flash media.
The Microdrive was a miniature, 1-inch hard disk drive released in 1998 by IBM. The idea was originally created in 1992 by duo Timothy J. Riley and Thomas R. Albrecht at the Almaden Research Center in San Jose. A team of engineers and designers at IBM's Fujisawa, Japan facility helped make the creation of the drive possible.
Perpendicular recording, also known as conventional magnetic recording (CMR), is a technology for data recording on magnetic media, particularly hard disks. It was first proven advantageous in 1976 by Shun-ichi Iwasaki, then professor of the Tohoku University in Japan, and first commercially implemented in 2005. The first industry-standard demonstration showing unprecedented advantage of PMR over longitudinal magnetic recording (LMR) at nanoscale dimensions was made in 1998 at IBM Almaden Research Center in collaboration with researchers of Data Storage Systems Center (DSSC) – a National Science Foundation (NSF) Engineering Research Center (ERCs) at Carnegie Mellon University (CMU).
A hybrid drive is a logical or physical computer storage device that combines a faster storage medium such as solid-state drive (SSD) with a higher-capacity hard disk drive (HDD). The intent is adding some of the speed of SSDs to the cost-effective storage capacity of traditional HDDs. The purpose of the SSD in a hybrid drive is to act as a cache for the data stored on the HDD, improving the overall performance by keeping copies of the most frequently used data on the faster SSD drive.
Travelstar was a brand of 2.5-inch hard disk drive (HDD) that was introduced by IBM in 1994 with the announcement of the Travelstar LP. At 12.5 mm high with two platters, they were available in 360, 540 and 720 MB capacities. Initial models were industry-leading for small form factor HDDs in terms of areal density, data transfer rates and shock tolerance (500g).
In 1953, IBM recognized the immediate application for what it termed a "Random Access File" having high capacity and rapid random access at a relatively low cost. After considering technologies such as wire matrices, rod arrays, drums, drum arrays, etc., the engineers at IBM's San Jose California laboratory invented the hard disk drive. The disk drive created a new level in the computer data hierarchy, then termed Random Access Storage but today known as secondary storage, less expensive and slower than main memory but faster and more expensive than tape drives.
A solid-state drive (SSD) is a type of solid-state storage device that uses integrated circuits to store data persistently. It is sometimes called semiconductor storage device, solid-state device, or solid-state disk.
Higher performance in hard disk drives comes from devices which have better performance characteristics. These performance characteristics can be grouped into two categories: access time and data transfer time .
dm-cache is a component of the Linux kernel's device mapper, which is a framework for mapping block devices onto higher-level virtual block devices. It allows one or more fast storage devices, such as flash-based solid-state drives (SSDs), to act as a cache for one or more slower storage devices such as hard disk drives (HDDs); this effectively creates hybrid volumes and provides secondary storage performance improvements.
