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Encyclopedia > Advanced Technology Attachment
ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom
ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom

Advanced Technology Attachment (ATA) is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. Many terms and synonyms for ATA exist, including abbreviations such as IDE, ATAPI, and UDMA. Download high resolution version (1880x546, 86 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1880x546, 86 KB) Wikipedia does not have an article with this exact name. ... An electrical connector is a device for joining electrical circuits together. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Typical hard drives of the mid-1990s. ... The CD-ROM (an abbreviation for Compact Disc Read-Only Memory (ROM)) is a non-volatile optical data storage medium using the same physical format as audio compact discs, readable by a computer with a CD-ROM drive. ...


With the market introduction of Serial ATA in 2003, the original ATA was retroactively renamed Parallel ATA (PATA). In line with the original naming, this article only covers Parallel ATA. SATA ports on a motherboard In computer hardware, Serial ATA (SATA - pronounced sat-uh or say-tah) is a computer bus technology primarily designed for transfer of data to and from a hard disk. ... A retronym is a type of neologism coined for an old object or concept whose original name has become used for something else or is no longer unique. ...


Parallel ATA standards only allow cable lengths up to 46 centimetres (18 inches) although cables up to 91 cm (36 inches) can be readily purchased. Because of this length limit, the technology normally appears as an internal computer storage interface. It provides the most common and the least expensive interface for this application.

Contents


History

ATA connection sockets on a PC motherboard located below RAM sockets
ATA connection sockets on a PC motherboard located below RAM sockets

Although the standard has always had the official name "ATA", marketing dictates caused an early version to be dubbed Integrated Drive Electronics (IDE). This is due to the drive controller being contained on the drive itself as opposed to a separate controller connected to the motherboard. The standard following IDE, Enhanced IDE (EIDE) allowed the support of drives having a storage capacity larger than 528 megabytes (504 mebibytes), up to 8.4 gigabytes. Although these new names originated in branding convention and not as an official standard, the terms IDE and EIDE often appear as if interchangeable with ATA. This may be attributed to the two technologies being introduced with the same consumable devices, these "new" ATA hard drives. With the introduction of Serial ATA around 2003, conventional ATA was retroactively renamed to Parallel ATA (P-ATA), referring to the method in which data travels over wires in this interface. Download high resolution version (1698x1110, 276 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1698x1110, 276 KB) Wikipedia does not have an article with this exact name. ... This article is about a unit of data measurement. ... dyn and The_Decryptors retarded way of saying megabyte. ... A gigabyte (symbol GB) is a unit of measurement in computers of one thousand million bytes (the same as one billion bytes in the short scale usage). ... SATA ports on a motherboard In computer hardware, Serial ATA (SATA - pronounced sat-uh or say-tah) is a computer bus technology primarily designed for transfer of data to and from a hard disk. ... An electrical connector is a device for joining electrical circuits together. ...


The interface at first only worked with hard disks, but eventually an extended standard came to work with a variety of other devices—generally those using removable media. Principally, these devices include CD-ROM and DVD-ROM drives, tape drives, and large-capacity floppy drives such as the Zip drive and SuperDisk drive. The extension bears the name Advanced Technology Attachment Packet Interface (ATAPI), with the full standard now known as ATA/ATAPI. The CD-ROM (an abbreviation for Compact Disc Read-Only Memory (ROM)) is a non-volatile optical data storage medium using the same physical format as audio compact discs, readable by a computer with a CD-ROM drive. ... DVD is an optical disc storage media format that is used for playback of movies with high video and sound quality and for storing data. ... DDS tape drive. ... A floppy disk is a data storage device that is composed of a ring of thin, flexible (i. ... The Zip drive is a medium-capacity Insert non-formatted text here removable disk storage system, introduced by Iomega in late 1994. ... Also known as the LS-120 and the later variant LS-240, the SuperDisk was introduced by 3Ms storage products group (later known as Imation) circa 1997 as a high-speed, high-capacity alternative to the 3. ...


The movement from programmed input/output (PIO) to direct memory access (DMA) provided another important transition in the history of ATA. As every computer word must be read by the CPU individually, PIO tends to be slow and use a lot of CPU. This is especially a problem on faster CPUs where accessing an address outside of the cacheable main memory (whether in the I/O map or the memory map) is a relatively expensive process. This meant that systems based around ATA devices generally performed disk-related activities much more slowly than computers using SCSI or other interfaces. However, DMA (and later Ultra DMA, or UDMA) greatly reduced the amount of processing time the CPU had to use in order to read and write the disks. This is possible because DMA and UDMA allow the disk controller to write data to memory directly, thus bypassing the CPU. The programmed input/output (PIO) intergface was the original method used to transfer data between the CPU (through the ATA controller) and an ATA device. ... Direct memory access (DMA) allows certain hardware subsystems within a computer to access system memory for reading and/or writing independently of the CPU. Many hardware systems use DMA including disk drive controllers, graphics cards, network cards, and sound cards. ... In computing, Input/output, or I/O, is the collection of interfaces that different functional units (sub-systems) of an information processing system use to communicate with each other, or the signals (information) sent through those interfaces. ... SCSI stands for Small Computer System Interface, and is a standard interface and command set for transferring data between devices on both internal and external computer buses. ...


ATA devices have suffered from a number of "barriers" in terms of how much data they can handle. However, new addressing systems and programming techniques have broken most of these barriers. Some of the ATA-specific barriers included: 504 MiB, ~8 GiB, ~32 GiB, and 128 GiB. A variety of other barriers have existed, usually due to device drivers and disk I/O layers in operating systems that did not correspond with ATA standards. dyn and The_Decryptors retarded way of saying megabyte. ... A gibibyte is a unit of information or computer storage. ... A device driver, often called a driver for short, is a computer program that enables another program, typically an operating system (OS), to interact with a hardware device. ... An operating system (OS) is an essential software program that manages the hardware and software resources of a computer. ...


The original ATA specification used a 28-bit addressing mode. This allowed for the addressing of 228 (268,435,456) sectors of 512 bytes each, resulting in a maximum capacity 137 gigabytes (128 GiB). The standard PC BIOS system supported up to 7.88 GiB (8.46 GB), with maximum of 1024 cylinders, 256 heads and 63 sectors. Unfortunately, when the lowest common denominators of the CHS limitations in the standard PC BIOS system and the IDE standard were combined, the system as a whole was left limited to a mere 504 mebibytes. BIOS translation and LBA were introduced, removing the need for the CHS structure on the drive itself to match that used by the BIOS and consequently allowing up to 7.88 GiB. With time, this limitation was itself lifted and first 32 GiB and then the full 128 GiB supported by ATA at that time became supported by PC BIOSes. Cylinder-head-sector, also known as CHS, is a method of addressing data on a hard drive. ... dyn and The_Decryptors retarded way of saying megabyte. ... Logical block addressing in computing maps conceptual data storage onto secondary storage. ...


The newer specification allows 48-bit addressing, and this extends the limit to 128 PiB (or 144 petabytes). Most operating systems have poor support for drives more than 2 TiB because that is the limit of their current file system, so it can be expected that will be the next drive size barrier in the near future. A pebibyte is a unit of information or computer storage. ... A petabyte is a unit of measurement in computers of one thousand million million (short-scale quadrillion) bytes. ... A tebibyte is a unit of information or computer storage, commonly abbreviated TiB. 1 tebibyte = 240 bytes = 1 099 511 627 776 bytes The tebibyte is closely related to the terabyte, which can either be a synonym for tebibyte, or refer to 1012 bytes = 1 000 000 000 000 bytes...


These size limitations come about because some part of the system is unable to deal with block addresses above some limit. This problem may manifest itself by the system thinking the size of a drive is only the limit value, or by the system refusing to boot and hanging on the BIOS screen at the point when drives are initialised. In some cases, a BIOS upgrade for the motherboard will resolve the problem. This problem is also found in older external FireWire disk enclosures, which limit the usable size of a disk to 128GB. By early 2005 most enclosures available have practically no limit. (Earlier versions of the popular Oxford 911 FireWire chipset had this problem. Later Oxford 911 versions and all Oxford 922 chips resolve the problem.) The FireWire color logo FireWire (also known as i. ...


Parallel ATA Interface

Until the introduction of Serial ATA, 40-pin connectors generally attached drives to a ribbon cable. Each cable has two or three connectors, one of which plugs into a controller that interfaces with the rest of the computer system. The remaining one or two connectors plug into drives. Parallel ATA cables transfer data 16 bits at a time. One occasionally finds cables that allow for the connection of three ATA devices onto one IDE channel, but in this case one drive remains read-only (this type of configuration virtually never occurs). IDE ribbon from http://www. ... A drawing of Advanced Technology Attachment (ATA) plug with some pin numbers shown. ... Left: 20-way grey ribbon cable with wire no. ...

Parallel ATA Pins
Pin Function Pin Function
1 Reset 2 Ground
3 Data 7 4 Data 8
5 Data 6 6 Data 9
7 Data 5 8 Data 10
9 Data 4 10 Data 11
11 Data 3 12 Data 12
13 Data 2 14 Data 13
15 Data 1 16 Data 14
17 Data 0 18 Data 15
19 Ground 20 Key
21 DDRQ 22 Ground
23 I/O Write 24 Ground
25 I/O Read 26 Ground
27 IOC HRDY 28 Cable Select
29 DDACK 30 Ground
31 IRQ 32 No Connect
33 Addr 1 34 GPIO_DMA66_Detect
35 Addr 0 36 Addr 2
37 Chip Select 1P 38 Chip Select 3P
39 Activity 40 Ground

ATA's ribbon cables had 40 wires for most of its history, but an 80-wire version appeared with the introduction of the Ultra DMA/66 (UDMA4) mode. All of the additional wires in the new cable are ground wires, interleaved with the previously defined wires. The interleaved ground wire reduces the effects of capacitive coupling between neighboring signal wires, thereby reducing crosstalk. Capacitive coupling is more of a problem at higher transfer rates, and this change was necessary to enable the 66 megabytes per second (MB/s) transfer rate of UDMA4 to work reliably. The faster UDMA5 and UDMA6 modes also require 80-conductor cables. Ground symbols The term ground or earth usually means a common return path in electrical circuits. ... In electronics, capacitive coupling is the transfer of energy from one circuit to another by means of the mutual capacitance between the circuits. ... In telecommunication, the term crosstalk (XT) has the following meanings: 1. ...


Though the number of wires doubled, the number of connector pins and the pinout remain the same as on 40-conductor cables, and the external appearance of the connectors is identical. Internally, of course, the connectors are different: The connectors for the 80-wire cable connect a larger number of ground wires to a smaller number of ground pins, while the connectors for the 40-wire cable connect ground wires to ground pins one-for-one. 80-wire cables usually come with three differently colored connectors (blue, gray & black) as opposed to uniformly colored 40-wire cable's connectors (all black). The gray connector has pin 28 CSEL not connected ; this makes it the slave position for drives configured cable select.


The ATA standard has always specified a maximum cable length of just 46 cm (18 inches). This can cause difficulties in connecting drives within a large computer case, or when mounting several physical drives into one computer, and it all but completely eliminates the possibility of using parallel ATA for external devices. Although longer cables are widely available on the market, it must be understood that they are outside the parameters set by the specifications. The same is true of the "rounded" cables also commonly available: The ATA standard describes flat cables with particular impedance and capacitance characteristics. This is of course not a guarantee that other cables will not work, but an indication that nonstandard cables should be used, if at all, with caution. In electrical engineering, Impedance is a measure of opposition to a sinusoidal electric current. ... // Definition Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. ...


If two devices attach to a single cable, one is commonly referred to as a master and the other as a slave. The master drive generally appears first when the computer's bios and/or operating system enumerates available drives. On old BIOSes (486 era and older) the drives are often misleadingly referred to by the bios as "C" for the master and "D" for the slave. Phoenix AwardBIOS on a standard PC BIOS, in computing, stands for Basic Input/Output System or Basic Integrated Operating System. ... An operating system (OS) is an essential software program that manages the hardware and software resources of a computer. ...


If there is a single device on a cable, in most cases it should be configured as master. However, some hard drives have a special setting called single for this configuration (Western Digital, in particular). Also, depending on the hardware and software available, a single drive on a cable can work reliably even though configured as the slave drive (this configuration is most often seen when a CDROM has a channel to itself). Western Digital Corporation NYSE: WDC (often abbreviated to WD) is a manufacturer of a large proportion of the worlds hard disks, and has a long history in the electronics industry as an IC maker and a storage products company. ...


A drive setting called cable select was described as optional in ATA-1 and has come into fairly widespread use with ATA-5 and later. A drive set to "cable select" automatically configures itself as master or slave, according to its position on the cable. Cable select is controlled by pin 28. The host controller grounds this pin; if a device sees that the pin is grounded, it becomes the master device; if it sees that pin 28 is open, the device becomes the slave device. Cable select is a setting on IDE devices such as hard drives and CDROM that allows the position of the drive on the cable to select whether the drive will act as master or slave. ...


With the 40-wire cable it was very common to implement cable select by simply cutting this wire between the two device connectors. This puts the slave device at the end of the cable, and the master on the "middle" connector. This arrangement eventually was standardized in later versions of the specification. Unfortunately, if there is just one device on the cable, this results in an unused "stub" of cable. This is undesirable, both for physical convenience and electrical reasons: The stub causes signal reflections, particularly at higher transfer rates. Signal reflection occurs because when a signal is transmitted along a transmission medium, such as a copper cable or an optical fibre, there is the possibility that some of the signal power will be reflected back to its origin, rather than being carried all the way along the cable to...


When the 80-wire cable was defined for use with UDMA4, these details were changed. The master device now goes at the end of the cable, so if there is only one device on the cable, there is no cable "stub" to cause reflections. Also, cable select is now implemented in the slave device connector, usually simply by omitting the contact from the connector body. Since 80-wire cables require special connectors anyway, this was a small additional effort. The standard also dictates color-coded connectors for easy identification by both installer and cable maker.


Although they are in extremely common use, the terms master and slave do not actually appear in current versions of the ATA specifications. The two devices are correctly referred to as device 0 (master) and device 1 (slave), respectively. It is a common myth that "the master drive arbitrates access to devices on the channel." In fact, the drivers in the host operating system perform the necessary arbitration and serialization. If device 1 is busy with a command then device 0 cannot start a command until device 1's command is complete, and vice versa. There is therefore no suggestion in the ATA protocols that one device has to ask the other if it can use the channel. Both are really "slaves" to the driver in the host OS.


ATA standards versions, transfer rates, and features

The following table shows the names of the versions of the ATA standards and the transfer modes and rates supported by each. Note that the transfer rate for each mode (for example, 66.7 MB/sec for UDMA4, commonly called "Ultra-DMA 66") gives its maximum theoretical transfer rate on the cable. This is simply two bytes multiplied by the effective clock rate, and presumes that every clock cycle is used to transfer end-user data. In practice, of course, protocol overhead reduces this value.


Congestion on the host bus to which the ATA controller is attached may also limit the maximum burst transfer rate. For example, the maximum data transfer rate for conventional PCI bus is 133 MB/sec, and this is shared among all active devices on the bus. 32-bit PCI expansion slots on a motherboard 64-bit PCI expansion slots inside a Power Macintosh G4 The Peripheral Component Interconnect standard (in practice almost always shortened to PCI) specifies a computer bus for attaching peripheral devices to a computer motherboard. ...


In addition, as of October 2005 no ATA hard drives exist capable of measured sustained transfer rates of above 80 MB/sec. Furthermore, sustained transfer rate tests do not give realistic throughput expectations for most workloads: They use I/O loads specifically designed to encounter almost no delays from seek time or rotational latency. Hard drive performance under most workloads is limited first and second by those two factors; the transfer rate on the bus is a distant third in importance. Therefore, transfer speed limits above 66 MB/sec only really affect performance when the hard drive can satisfy all I/O requests by reading from its internal cache — a very unusual situation, especially considering that such data is usually already buffered by the operating system. Ongoing events • Abramoff-Reed gambling scandal • Atlantic hurricane season • Avian influenza (H5N1) outbreak in Asia • Bali bombings investigation • California wildfires • DeLay political financing scandal • Dengue outbreak in Singapore • FIDE World Chess Championship 2005 • Fuel prices • Gomery Comm. ... Typical hard drives of the mid-1990s. ... Look up cache in Wiktionary, the free dictionary. ...

Standard Other Names Transfer Modes Added (MB/sec) Maximum disk size Other New Features ANSI Reference
ATA-1 ATA, IDE PIO 0,1,2 (3.3, 5.2, 8.3)
Single-word DMA 0,1,2 (2.1, 4.2, 8.3)
Multi-word DMA 0 (4.2)
up to 528 MB X3.221-1994
(obsolete since 1999)
ATA-2 EIDE, Fast ATA,
Fast IDE, Ultra ATA
PIO 3,4: (11.1, 16.6)
Multi-word DMA 1,2 (13.3, 16,6)
up to 8.4 GB 24-bit LBA X3.279-1996
(obsolete since 2001)
ATA-3 EIDE " up to 137 GB 28-bit LBA ()
S.M.A.R.T., Security
X3.298-1997
(obsolete since 2002)
ATA/ATAPI-4 ATAPI-4, ATA-4, Ultra ATA/33 Ultra DMA 0,1,2 (16.7, 25.0, 33.3)
aka Ultra-DMA/33
Support for CD-ROM, etc.,
via ATAPI packet commands
NCITS 317-1998
ATA/ATAPI-5 ATA-5, Ultra ATA/66 Ultra DMA 3,4 (44.4, 66.7)
aka Ultra DMA 66
80-wire cables NCITS 340-2000
ATA/ATAPI-6 ATA-6, Ultra ATA/100 UDMA 5 (100)
aka Ultra DMA 100
up to 144 PB 48-bit LBA
Automatic Acoustic Management
NCITS 347-2001
ATA/ATAPI-7 ATA-7, Ultra ATA/133 UDMA 6 (133)
aka Ultra DMA 133
SATA/150
SATA 1.0, Streaming feature set, long logical/physical sector feature set for non-packet devices NCITS 361-2002
ATA/ATAPI-8 ATA-8 -- -- in progress

In August 2004, Sam Hopkins and Brantley Coile of Coraid specified a lightweight protocol to carry ATA commands over Ethernet instead of directly connecting them to a PATA host controller. This permitted the established block protocol to be reused in Network-attached storage applications. The programmed input/output (PIO) intergface was the original method used to transfer data between the CPU (through the ATA controller) and an ATA device. ... Self-Monitoring, Analysis, and Reporting Technology, or S.M.A.R.T., is a monitoring system for computer hard disks to detect and report on various indicators of reliability, in the hope of anticipating failures. ... SATA ports on a motherboard In computer hardware, Serial ATA (SATA - pronounced sat-uh or say-tah) is a computer bus technology primarily designed for transfer of data to and from a hard disk. ... Coraid, Inc. ... Ethernet is a frame-based computer networking technology for local area networks (LANs). ... Network-attached storage (NAS) A term used to refer to storage elements that connect to a network and provide file access services to computer systems. ...


External links


  Results from FactBites:
 
Advanced Technology Attachment - Wikipedia, the free encyclopedia (2198 words)
This may be attributed to the two technologies being introduced with the same consumable devices, these "new" ATA hard drives.
ATA devices have suffered from a number of "barriers" in terms of how much data they can handle.
Until the introduction of Serial ATA, 40-pin connectors generally attached drives to a ribbon cable.
  More results at FactBites »

 
 

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