ATA Interface Parallel ATA (PATA), originally AT Attachment, is an interface
standard for the connection of storage devices such as hard disks, floppy drives,
and optical disc drives in computers. The standard is maintained by X3/INCITS committee.
It uses the underlying AT Attachment (ATA) and AT Attachment Packet Interface (ATAPI)
standards. Parallel ATA cables have a maximum allowable length of only 18 in (457
mm), and only two devices are supported. As well, PATA does not support hot removal
and add of drives. Because of these limitations, Parallel ATA has largely been replaced
by Serial ATA (SATA) in newer systems, and for Windows Server, is only allowed to be used for CD and DVD devices.
Boot 2.2TB+ Disk Volume
Controllers supporting a boot device with a capacity
greater than 2.2 terabytes must comply with the following requirements:
Small Computer System Interface (SCSI) and SCSI-compatible storage controllers must
comply with section 14, "SCSI Driver Model", of UEFI specification version 2.3.1.
The Internet Small Computer System Interface (iSCSI) boot initiator must comply
with section 15, "iSCSI Boot", of UEFI specification version 2.3.
The storage controller must support T10 SBC3 Read Capacity (16) command in the UEFI
device driver and the Windows device driver. If Advanced Technology Attachment (ATA)
or an Advanced Technology Attachment with Packet Interface (ATAPI) storage controller
or disk drive is used, the controller firmware or driver must implement SCSI ATA
Translation according T10 SAT3 specifications.
The storage controller must report the exact size of the boot disk drive in the
EFI shell and in the Windows operating system.
Option ROMs in host controllers and adapters for any interface
type, including RAID controllers, that provide boot support must fully support extended
Int13h functions (functions 4xh) as defined in BIOS Enhanced Disk Drive Services
- 3 [T13-D1572], Revision 3 or later. Logical block addressing is the only addressing
It is recommended that controllers also support booting using the Extensible Firmware
Interface (EFI) and implement device paths as defined in EDD-3.
SD/eMMC/NAND flash controllers do not have Option ROM, so UEFI support is required.
FibreChannel Interface ANSI developed the FC Standard in 1988 as a practical
and expandable method of using fiber optic cabling to transfer data among desktop
computers, workstations, mainframes, supercomputers, storage devices, and display
devices. ANSI later changed the standard to support copper cabling; today, some
kinds of FC use two-pair copper wire to connect the outer four pins of a nine-pin
FibreChannel-over-Ethernet Interface Fibre Channel over Ethernet (FCoE) is
a computer network technology that encapsulates Fibre Channel frames over Ethernet
networks. This allows Fibre Channel to use Ethernet networks while preserving the
Fibre Channel protocol. The specification was part of the International Committee
for Information Technology Standards T11 FC-BB-5 standard published in 2009. FCoE
maps Fibre Channel directly over Ethernet while being independent of the Ethernet
forwarding scheme. The FCoE protocol specification replaces the FC0 and FC1 layers
of the Fibre Channel stack with Ethernet. By retaining the native Fibre Channel
constructs, FCoE is meant to integrate with existing Fibre Channel networks and
management software. FCoE operates directly above Ethernet in the network protocol
stack, in contrast to iSCSI which runs on top of TCP and IP. As a consequence, FCoE
is not routable at the IP layer, and will not work across routed IP networks. Since
classical Ethernet had no priority-based flow control, unlike Fibre Channel, FCoE
required enhancements to the Ethernet standard to support a priority-based flow
control mechanism (to reduce frame loss from congestion). The IEEE standards body
added priorities in the data center bridging Task Group.
iSCSI Interface iSCSI is an acronym for Internet Small Computer System Interface,
an Internet Protocol (IP)-based storage networking standard for linking data storage
facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate
data transfers over intranets and to manage storage over long distances. iSCSI 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.
The protocol allows clients (called initiators) to send SCSI commands (CDBs) to
SCSI storage devices (targets) on remote servers. It is a storage area network (SAN)
protocol, allowing organizations to consolidate storage into data center storage
arrays while providing hosts (such as database and web servers) with the illusion
of locally attached disks. Unlike Fibre Channel, which requires special-purpose
cabling, iSCSI can be run over long distances using existing network infrastructure.
iSCSI was submitted as draft standard in March 2000
N-Port ID Virtualization N-Port ID Virtualization, or NPIV, is a Fibre Channel
facility that allows multiple N-Port IDs to share a single physical N-Port. N-Port
sharing allows multiple Fibre Channel initiators to utilize a single physical port,
easing hardware requirements in SAN design, especially where virtual SANs are used.
NPIV is defined by the Technical Committee T11 within the INCITS standards body.
NPIV allows end users to effectively virtualize the Fibre Channel HBA functionality
such that each Virtual Machine (VM) running on a server can share a pool of HBAs,
yet have independent access to its own protected storage. This sharing enables administrators
to leverage standard SAN management tools and best practices, such as fabric zoning
and LUN mapping/masking, and enables the full use of fabric-based quality-of-service
and accounting capabilities. It also provides efficient utilization of the HBAs
in the server while providing a high level of data protection.
RAID Adapter RAID (redundant array of independent disks) is a storage technology
that combines multiple disk drive components into a logical unit for the purposes
of data redundancy and performance improvement. Data is distributed across the drives
in one of several ways, referred to as RAID levels, depending on the specific level
of redundancy and performance required. Windows Server Certification Requirements
specify that RAID controllers and RAID systems must support, at a minimum, one of:
RAID1, RAID 5, RAID6 or RAID 1/0, with RAID levels greater than RAID 0 providing
protection against unrecoverable (sector) read errors, as well as whole disk failure.
Serial Attached SCSI (SAS) is a point-to-point serial protocol
that moves data to and from computer storage devices such as hard drives and tape
drives. SAS replaces the older Parallel SCSI (Small Computer System Interface),
bus technology that first appeared in the mid-1980s. SAS uses the standard SCSI
command set. The T10 technical committee of the International Committee for Information
Technology Standards (INCITS) develops and maintains the SAS protocol; the SCSI
Trade Association (SCSITA) promotes the technology. A typical Serial Attached SCSI
system consists of the following basic components:
An Initiator: a device that originates device-service and task-management requests
for processing by a target device and receives responses for the same requests from
other target devices. Initiators may be provided as an on-board component on the
motherboard (as is the case with many server-oriented motherboards) or as an add-on
host bus adapter.
A Target: a device containing logical units and target ports that receives device
service and task management requests for processing and sends responses for the
same requests to initiator devices. A target device could be a hard disk or a disk
A Service Delivery Subsystem: the part of an I/O system that transmits information
between an initiator and a target. Typically cables connecting an initiator and
target with or without expanders and backplanes constitute a service delivery subsystem.
Expanders: devices that form part of a service delivery subsystem and facilitate
communication between SAS devices. Expanders facilitate the connection of multiple
SAS End devices to a single initiator port.
The SAS bus operates point-to-point while the SCSI bus is "multi-drop" (electrically
parallel), reducing contention. SAS has no termination issues and does not require
terminator packs like parallel SCSI. SAS eliminates clock skew. SAS allows up to
65,535 devices through the use of expanders, while Parallel SCSI has a limit of
8 or 16 devices on a single channel. SAS allows a higher transfer speeds than most
parallel SCSI standards. SAS devices feature dual ports, allowing for redundant
SATA Interface Serial ATA (SATA) is a computer bus interface that connects
host bus adapters to mass storage devices such as hard disk drives and optical drives.
Serial ATA replaces Parallel ATA or PATA, offering several advantages over the older
interface: reduced cable size and cost (seven conductors instead of 40), native
hot swapping, faster data transfer through higher signaling rates, and more efficient
transfer through an (optional) I/O queuing protocol. SATA host adapters and devices
communicate via a high-speed serial cable over two pairs of conductors. To ensure
backward compatibility with legacy ATA software and applications, SATA uses the
same basic ATA and ATAPI command-set as legacy ATA devices.