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.
In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer. A driver provides a software interface to hardware devices, enabling operating systems and other computer programs to access hardware functions without needing to know precise details about the hardware being used.
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.
In computing, iSCSI is an acronym for Internet Small Computer Systems Interface, an Internet Protocol (IP)-based storage networking standard for linking data storage facilities. It provides block-level access to storage devices by carrying SCSI commands over a TCP/IP network. iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances. It can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet and can enable location-independent data storage and retrieval.
Disk formatting is the process of preparing a data storage device such as a hard disk drive, solid-state drive, floppy disk or USB flash drive for initial use. In some cases, the formatting operation may also create one or more new file systems. The first part of the formatting process that performs basic medium preparation is often referred to as "low-level formatting". Partitioning is the common term for the second part of the process, making the data storage device visible to an operating system. The third part of the process, usually termed "high-level formatting" most often refers to the process of generating a new file system. In some operating systems all or parts of these three processes can be combined or repeated at different levels and the term "format" is understood to mean an operation in which a new disk medium is fully prepared to store files. Some formatting utilities allow distinguishing between a quick format, which does not erase all existing data and a long option that does erase all existing data.
In computer hardware, a host controller, host adapter, or host bus adapter (HBA) connects a computer, which acts as the host system, to other network and storage devices. The terms are primarily used to refer to devices for connecting SCSI, Fibre Channel and SATA devices. Devices for connecting to IDE, Ethernet, FireWire, USB and other systems may also be called host adapters.
The USB mass storage device class is a set of computing communications protocols, specifically a USB Device Class, defined by the USB Implementers Forum that makes a USB device accessible to a host computing device and enables file transfers between the host and the USB device. To a host, the USB device acts as an external hard drive; the protocol set interfaces with a number of storage devices.
An Option ROM is a piece of firmware that resides in BIOS or on an expansion card, which gets shadowed into memory and executed to initialise the device and register it with the BIOS. It is essentially a driver that interfaces between BIOS services and hardware.
ATA over Ethernet (AoE) is a network protocol developed by the Brantley Coile Company, designed for simple, high-performance access of block storage devices over Ethernet networks. It is used to build storage area networks (SANs) with low-cost, standard technologies.
SCSI target devices provide a number of SCSI log pages. These can be interrogated by a Log Sense command and in some cases can be set by a Log Select command. The Log Sense and Log Select commands include a 6-bit address field, allowing for 64 possible log pages. There is a standard map of log page addresses below. Note that any given SCSI device type will only support a subset of these log pages.
Most recent SCSI enclosure products support a protocol called SCSI Enclosure Services (SES). The initiator can communicate with the enclosure using a specialized set of SCSI commands to access power, cooling, and other non-data characteristics.
SCSI Enclosure Services (SES) devices contains a number of elements, each of which is defined by a one byte SCSI element code. There are many different element codes defined to cover various devices as shown in the list below.
Parallel SCSI is the earliest of the interface implementations in the SCSI family. SPI is a parallel bus; there is one set of electrical connections stretching from one end of the SCSI bus to the other. A SCSI device attaches to the bus but does not interrupt it. Both ends of the bus must be terminated.
The Enclosure Services Interface (ESI) is a computer protocol used in SCSI enclosures. This is part of a chain of connections that allows a host computer to communicate with the enclosure to access its power, cooling, and other non-data characteristics. This overall approach is called SCSI attached enclosure services:
SCSI standalone enclosure services is a computer protocol used mainly with disk storage enclosures. It allows a host computer to communicate with the enclosure to access its power, cooling, and other non-data characteristics.
Count key data (CKD) is a direct-access storage device (DASD) data recording format introduced in 1964 by IBM with its IBM System/360 and still being emulated on IBM mainframes. It is a self-defining format with each data record represented by a Count Area that identifies the record and provides the number of bytes in an optional Key Area and an optional Data Area. This is in contrast to devices using fixed sector size or a separate format track.
The introduction of Serial Attached SCSI (SAS) as the most recent evolution of SCSI required redefining the related standard for enclosure management, called SCSI Enclosure Services. SES-2, or SCSI Enclosure Management 2 first revision, was introduced in 2002 and is now at revision 20. SES-2 SCSI Enclosure Services (SES) permit the management and sense the state of power supplies, cooling devices, LED displays, indicators, individual drives, and other non-SCSI elements installed in an enclosure. SES2 alerts users about drive, temperature and fan failures with an audible alarm and a fan failure LED.
In computer storage, SAF-TE is an industry standard to interface an enclosure to a (parallel) SCSI subsystem to gain access to information or control for various elements and parameters. These include temperature, fan status, slot status (populated/empty), door status, power supplies, alarms, and indicators. Practically, any given SAF-TE device will only support a subset of all possible sensors or controls.
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.
The bio(4) pseudo-device driver and the bioctl(8) utility implement a generic RAID volume management interface in OpenBSD and NetBSD. The idea behind this software is similar to ifconfig, where a single utility from the operating system can be used to control any RAID controller using a generic interface, instead of having to rely on plentiful of proprietary and custom RAID management utilities specific for each given hardware RAID manufacturer. Features include monitoring of the health status of the arrays, controlling identification through blinking the LEDs and managing of sound alarms, and specifying hot spare disks. Additionally, the softraid configuration in OpenBSD is delegated to bioctl as well; whereas the initial creation of volumes and configuration of hardware RAID is left to card BIOS as non-essential after the operating system has already been booted. Interfacing between the kernel and userland is performed through the ioctl system call through the /dev/bio pseudo-device.
