Parallel ATA (PATA), originally AT Attachment, is an interface standard for the connection of storage devices such as hard disk drives, floppy disk drives, and optical disc drives in computers. The standard is maintained by the X3/INCITS committee. It uses the underlying AT Attachment (ATA) and AT Attachment Packet Interface (ATAPI) standards.
A hard disk drive (HDD), hard disk, hard drive, or fixed disk, is an electromechanical data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (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 or retrieved in any order and not only sequentially. HDDs are a type of non-volatile storage, retaining stored data even when powered off.
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interfaces. SCSI is most commonly used for hard disk drives and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices. The SCSI standard defines command sets for specific peripheral device types; the presence of "unknown" as one of these types means that in theory it can be used as an interface to almost any device, but the standard is highly pragmatic and addressed toward commercial requirements.
Serial ATA is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard to become the predominant interface for storage devices.
Network-attached storage (NAS) is a file-level computer data storage server connected to a computer network providing data access to a heterogeneous group of clients. NAS is specialized for serving files either by its hardware, software, or configuration. It is often manufactured as a computer appliance – a purpose-built specialized computer. NAS systems are networked appliances which contain one or more storage drives, often arranged into logical, redundant storage containers or RAID. Network-attached storage removes the responsibility of file serving from other servers on the network. They typically provide access to files using network file sharing protocols such as NFS, SMB, or AFP. From the mid-1990s, NAS devices began gaining popularity as a convenient method of sharing files among multiple computers. Potential benefits of dedicated network-attached storage, compared to general-purpose servers also serving files, include faster data access, easier administration, and simple configuration.
Quantum Corporation is a manufacturer of data storage devices and systems, including tape drive and disk-based systems. The company's headquarters is in San Jose, California. From its founding in 1980 until 2001, it was also a major disk storage manufacturer, and was based in Milpitas, California. Quantum sold its hard disk drive business to Maxtor in 2001 and now focuses on integrated storage systems.
Floptical refers to a type of floppy disk drive that combines magnetic and optical technologies to store data on media similar to standard 3 1⁄2-inch floppy disks. The name is a portmanteau of the words "floppy" and "optical". It refers specifically to one brand of drive and disk system, but is also used more generically to refer to any system using similar techniques.
S.M.A.R.T. is a monitoring system included in computer hard disk drives (HDDs), solid-state drives (SSDs), and eMMC drives. Its primary function is to detect and report various indicators of drive reliability with the intent of anticipating imminent hardware failures.
A disk enclosure is a specialized casing designed to hold and power disk drives while providing a mechanism to allow them to communicate to one or more separate computers.
Hard coding is the software development practice of embedding data directly into the source code of a program or other executable object, as opposed to obtaining the data from external sources or generating it at run-time. Hard-coded data typically can only be modified by editing the source code and recompiling the executable, although it can be changed in memory or on disk using a debugger or hex editor. Data that are hard-coded usually represent unchanging pieces of information, such as physical constants, version numbers and static text elements. Softcoded data, on the other hand, encode arbitrary information like user input, HTTP server responses, or configuration files, and are determined at runtime.
Conner Peripherals was a company that manufactured hard drives for personal computers. Conner Peripherals was founded in 1985 by Seagate Technology co-founder and San Jose State University alumnus Finis Conner. In 1986, they merged with CoData, a Colorado start-up founded by MiniScribe founders Terry Johnson and John Squires. CoData was developing a new type of small hard disk that put the capacity of a 5.25-inch drive into the smaller 3.5-inch format. The CoData drive was the first Conner Peripherals product. The company was partially financed by Compaq, who was also a major customer for many years.
Disk packs and disk cartridges were early forms of removable media for computer data storage, introduced in the 1960s.
Storage Module Drive (SMD) is a family of storage devices that were first shipped by Control Data Corporation in December 1973 as the CDC 9760 40 MB (unformatted) storage module disk drive. The CDC 9762 80 MB variant was announced in June 1974 and the CDC 9764 150 MB and the CDC 9766 300 MB variants were announced in 1975. A non-removable media variant family of 12, 24 and 48 MB capacity, the MMD, was then announced in 1976. This family's interface, SMD, derived from the earlier Digital RP0x interface, was documented as ANSI Standard X3.91M - 1982, Storage Module Interfaces with Extensions for Enhanced Storage Module Interfaces.
Write precompensation is a technical aspect of the design of hard disks, floppy disks and other digital magnetic recording devices. It is the modification of the analog write signal, shifting transitions somewhat in time, in such a way as to ensure that the signal that will later be read back will be as close as possible to the unmodified write signal. It is required because of the non-linear properties of magnetic recording surfaces.
In computer storage, disk buffer is the embedded memory in a hard disk drive (HDD) acting as a buffer between the rest of the computer and the physical hard disk platter that is used for storage. Modern hard disk drives come with 8 to 256 MiB of such memory, and solid-state drives come with up to 4 GB of cache memory.
The most widespread standard for configuring multiple hard disk drives is RAID, which comes in a number of standard configurations and non-standard configurations. Non-RAID drive architectures also exist, and are referred to by acronyms with similarity to RAID, several tongue-in-cheek
The floppy disk is a data storage and transfer device which was ubiquitous from the mid-1970s well into the 2000s. Besides the 3½-inch and 5¼-inch formats used in IBM PC compatible systems, or the 8-inch format that preceded them, many proprietary floppy disk formats were developed, either using a different disk design or special layout and encoding methods for the data held on the disk.
Hard disk drives are accessed over one of a number of bus types, including parallel ATA, Serial ATA (SATA), SCSI, Serial Attached SCSI (SAS), and Fibre Channel. Bridge circuitry is sometimes used to connect hard disk drives to buses with which they cannot communicate natively, such as IEEE 1394, USB, SCSI and Thunderbolt.
