Ata, Ide, Ultra Ata, Ultra Dma
ATA, IDE, ULTRA ATA , ULTRA DMA
Overview
The ATA (Advanced Technology Attachment) standard is a standard interface that allows you to connect storage peripherals to PC computers. The ATA standard was developed on May 12, 1994 by the ANSI (document X3.221-1994).
Despite the official name "ATA", this standard is better known by the commercial term IDE (Integrated Drive Electronics) or Enhanced IDE (EIDE or E-IDE).
The ATA standard was originally intended for connecting hard drives, however an extension called ATAPI (ATA Packet Interface) was developed in order to be able to interface other storage peripherals (CD-ROM drives, DVD-ROM drives, etc.) on an ATA interface.
Since the Serial ATA standard (written S-ATA or SATA) has emerged, which allows you to transfer data over a serial link, the term "Parallel ATA" (written PATA or P-ATA) sometimes replaces the term "ATA" in order to differentiate between the two standards.
The newest ATA-related standard is Ultra ATA, which also goes by several other names including Ultra DMA, ATA-33, and DMA-33. It is also sometimes called ATA-3, which it is not. Ultra ATA is not a formal standard but rather a term that refers to the use of the higher-speed DMA-33 transfer mode (multiword DMA mode 3), running at 33.3 MB/s. Special error detection and correction logic (CRC) is used to support the use of this high-speed mode over a standard IDE/ATA ribbon cable (which has not changed since transfer rates were below 5 MB/s and can now be a problem in terms of corruption when used at very high speeds). Ultra ATA maintains backward compatibility with the older standards upon which it is based (ATA-2 and ATA).
Drives that support Ultra ATA allow the use of the high-speed DMA-33 transfer mode, but are otherwise the same as other ATA-2/EIDE drives. Ultra ATA requires both a hard disk and a system BIOS/chipset that support the Ultra ATA protocol.
The Principle
The ATA standard allows you to connect storage peripherals directly with the motherboard thanks to a ribbon cable, which is generally made up of 40 parallel wires and three connectors (usually a blue connector for the motherboard and a black connector and a grey connector for the two storage peripherals).
On the cable, one of the peripherals must be declared the master cable and the other the slave. It is understood that the far connector (black) is reserved for the master peripheral and the middle connector (grey) for the slave peripheral. A mode called cable select (abbreviated as CS or C/S) allows you to automatically define the master and slave peripherals as long as the computer's BIOS supports this functionality.
PIO Modes
Data transmission occurs thanks to a protocol called PIO (Programmed Input/Output), which allows peripherals to exchange data with the RAM with the help of commands managed directly by the processor. However, large data transfers can quickly impose a large workload on the processor and slow down the whole system. There are 5 PIO modes that define the maximum throughput:
DMA Modes
The DMA (Direct Memory Access) technique allows computers to free up the processor by allowing each of the peripherals to directly access the memory. There are two types of DMA modes:
* The "single word" DMA, which permits the transfer of one single word (2 bytes or 16 bits) during each transfer session
* The "multi-word" DMA, which permits the successive transfer of several words in each transfer session
The following table lists the different DMA modes and their associated throughputs:
Ultra DMA
The ATA standard is originally based on an asynchronous transfer mode, i.e. sending commands and sending data are clocked to the bandwidth of the bus and occur at each rising edge of the clock signal. However, sending commands and sending data do not occur simultaneously, i.e. a command cannot be sent as long as the data has not been received and vice versa.
In order to increase the data throughput, it may seem logical to increase the clock signal frequency. However, on an interface where data are sent in parallel, increasing the frequency poses problems of electromagnetic interference.
Thus, Ultra DMA (sometimes abbreviated as UDMA) was designed with the goal of optimising the ATA interface as much as possible. The first concept of Ultra DMA consists in using the rising edges as well as the falling edges of the signal for the data transfers, meaning an increase in speed of 100% (with the throughput increasing from 16.6 Mb/s to 33.3 Mb/s). Moreover, Ultra DMA introduces the use of CRC codes for the detection of transmission errors. Thus, the different Ultra DMA modes define the frequency of data transfer. When an error occurs (when the received CRC does not correspond to the data), the transfer occurs in a lower Ultra DMA mode, or even without Ultra DMA.
With the introduction of Ultra DMA mode 4, a new type of cable ribbon was introduced in order to limit crosstalk. This type of ribbon cable adds 40 wires (for a total of 80) that are interleaved with the data wires in order to isolate them and have the same connectors as the 40-wire cable ribbon.
Only Ultra DMA modes 2, 4, 5 and 6 are truly implemented by hard drives.
ATA Standards
The ATA standard comes in several versions, which were introduced successively:
ATA-1
The ATA-1 standard, better known as IDE, allows you to connect two peripherals on a 40-wire cable and offers an 8 or 16-bit transfer rate with a throughput of the order of 8.3 Mb/s. ATA-1 defines and supports PIO modes (Programmed Input/Output) 0, 1 and 2 as well as multi-word DMA mode (Direct Memory Access) 0.
ATA-2
The ATA-2 standard, better known as EIDE (or sometimes Fast ATA, Fast ATA-2 or Fast IDE), allows you to connect two peripherals on a 40-wire cable and offers an 8 or 16-bit transfer rate with a throughput of the order of 16.6 Mb/s.
ATA-2 supports PIO modes 0, 1, 2, 3 and 4 and multi-word DMA modes 0, 1 and 2. In addition, ATA-2 allows you to increase the maximum disk size from 528 Mb, which is imposed by the ATA-1 standard, to 8.4 Gb thanks to LBA (Large Block Addressing).
ATA-3
The ATA-3 standard (also called ATA Attachment 3 Interface) represents a minor revision of ATA-2 (with downward compatibility) and was published in 1997 under the standard X3.298-1997. The ATA-3 standard brings the following improvements:
* Improved reliability: ATA-3 enables the increased reliability of high-speed transfers
* S.M.A.R.T (Self-Monitoring Analysis and Reporting Technology: a function intended to improve reliability and prevent against failures
* Security function: the peripherals can be protected by a password added to the BIOS. When the computer is started, it verifies that the password encoded in the BIOS corresponds to the one stored on the drive. This allows you to prevent the drive from being used on a different computer.
ATA-3 is not a new mode but supports PIO modes 0, 1, 2, 3 and 4 as well as DMA modes 0, 1 and 2.
ATA-4
The ATA-4 standard, or Ultra-ATA/33, was defined in 1998 under the standard ANSI NCITS 317-1998. ATA-4 modifies the LBA mode in order to increase the disk size limit to 128-Gb drives.
LBA addresses in ATA-4 are 28-bit. Each sector represents 512 bytes, so the exact disk size limit in LBA mode is as follows:
228*512 = 137 438 953 472 bytes
137 438 953 472/(1024*1024*1024)= 128 Gb
ATA-5
In 1999, the ATA-5 standard defined two new transfer modes: Ultra DMA modes 3 and 4 (mode 4 is also called Ultra ATA/66 or Ultra DMA/66). What is more, it offers automatic detection of the type of ribbon cables being used (80 or 40 wires).
ATA-6
Since 2001, ATA-6 defines Ultra DMA/100 (also called Ultra DMA mode 5 or Ultra-ATA100), which allows drives to theoretically reach throughputs of 100 Mb/s.
In addition, ATA-6 defines a new functionality, called Automatic Acoustic Management (AAM), which allows drives that support this function to automatically adjust access speeds in order to reduce running noise.
Finally, the ATA-6 standard allows a 48-bit LBA of the sectors of the hard drive, called LBA48 (Logical Block Addressing 48 bits). Thanks to LBA48, it is possible to use 2^48 hard drives with 512 bytes per sector, which equals a disk size limit of 2 petabytes.
ATA-7
The ATA-7 standard defines Ultra DMA/133 (also called Ultra DMA mode 6 or Ultra-ATA133), which allows drives to theoretically reach throughputs of 133 Mb/s.
Re: Ata, Ide, Ultra Ata , Ultra Dma
GENERAL INFORMATION
Ultra DMA is a new protocol for the ATA/IDE hard disk drive interface that doubles the current burst data transfer rate to 33 megabytes (MB) per second. This technology is capable of transferring twice as much data per clock cycle and provides a path for disk drive vendors to scale the performance of their products. A user can potentially benefit from faster disk reads and writes, resulting in less waiting time when starting a system or application. The Ultra DMA protocol is implemented in all new Intel PCIsets (beginning with the 430TX), Intel AGPsets (beginning with the 440LX), and disk drive products from all leading vendors.
To utilize Ultra DMA your system must have all of the following elements:
- Ultra DMA compatible logic on your system motherboard (the Intel 430TX PCIset and 440LX AGPset both contain this logic) or on an Ultra DMA PCI adapter card (for installed systems).
- Ultra DMA compatible BIOS
- an Ultra DMA-aware device driver for your operating system
- an Ultra DMA compatible IDE device (disk drive, CD-ROM)
A platform based on either the Intel 430TX PCIset or the Intel 440LX AGPset is a very cost effective method of employing an Ultra DMA drive, as the control logic is integrated onto the motherboard. New systems based on earlier PCIsets or installed systems can take advantage of Ultra DMA's 33 MB/s transfer rate by installing a PCI Ultra DMA IDE controller card.
Both the Intel 430TX PCIset and the Intel 440LX AGPset continue to support legacy IDE/ATA drives at 16.6 MB/s.
The Ultra DMA protocol is a "wider" channel for data traffic to flow to and from your hard drive. Performance gains due to Ultra DMA are dependent on the rate at which your specific drive sends data through the channel. Because legacy IDE protocol (16.6 MB/s) has become a speed limiter, initial Ultra DMA hard drive products with current mechanical designs will achieve moderate performance increases (< 10 %). New hard drive products that transmit and receive data at higher rates will result in greater performance.
HARDWARE REQUIREMENTS
An Ultra DMA capable system includes an IDE host controller that is capable of transferring data between a system and IDE drives utilizing the Ultra DMA protocol. This may reside on a motherboard in an integrated core logic solution (such as the Intel 430TX PCIset or Intel 440LX AGPset) or on a PCI add-on card. The system must also have a disk drive which supports the Ultra DMA protocol. Cables for an Ultra DMA solution are identical to those used for legacy drives.
If the Ultra DMA drive is enabled by the integrated logic in an Intel PCIset directly on your motherboard, it can be used in conjunction with the latest Intel Bus Master IDE driver (Intel's Bus Master IDE driver for Windows* '95 ver 3.0 - or later). Contact you operating system vendor or system manufacturer for bus master drivers for other operating systems.
The IDE host controller supported is the PCI to ISA bridge component included in both Intel's 430TX PCIset and Intel's 440LX AGPset. Specifically, the 82371AB PCI Bus Master IDE Controller in both the Intel 430TX PCIset and the Intel 440LX AGPset.
SOFTWARE REQUIREMENTS
Ultra DMA disk drive supporting software must include the following for a system to function correctly:
1. Ultra DMA compatible BIOS
2. A multi-tasking operating system (OS) such as Windows* '95
3. An Ultra DMA-aware device driver for your operating system
Contact your PC and/or disk drive manufacturer for more information in determining a system's ability to support Ultra DMA.
System BIOS is responsible for configuring the IDE host controller and IDE drives based on the capabilities of the IDE drives. There is no convenient way to find out if your system BIOS is Bus Master or Ultra DMA compatible. Contact your system manufacturer to determe if your BIOS supports Ultra DMA and has been validated with Ultra DMA and Bus Master IDE.
