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.


Q1. What is the Ultra DMA protocol and what does it do?

A1. 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:

  1. 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).
  2. Ultra DMA compatible BIOS
  3. an Ultra DMA-aware device driver for your operating system
  4. an Ultra DMA compatible IDE device (disk drive, CD-ROM)

Q2. Do I need the 430TX or the 440LX to use an Ultra DMA drive or vice-versa?

A2. 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.

Q3. How does Ultra DMA affect my system performance?

A3. 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.

Q4. How can I purchase a system with Ultra DMA capability?

A4. Contact your PC manufacturer and request a list of PC models that have an Ultra DMA hard drive or can be upgraded without the extra cost of a controller card. For specific disk drive availability, contact individual drive manufacturers or their authorized sales outlets.

Q5. Do I already have an Ultra DMA drive in my system?

A5. Contact your PC manufacturer or disk drive vendor to determine if your system contains an Ultra DMA disk drive.


Q1. What hardware is needed to install an Ultra DMA drive on a system?

A1. 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.

Q2. Can I use Intel's Bus Master IDE drivers with an Ultra DMA drive?

A2. 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.

Q3. Which Ultra DMA host controllers are supported by Intel's Bus Master IDE drivers?

A3. 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.

Other Ultra DMA host controllers are not supported by the Intel Bus Master IDE drivers.

Q4. Can I use Ultra DMA capable and standard IDE drives in the same system?

A4. Yes, an Ultra DMA capable and standard IDE drives can be used in the same system. Ultra DMA drives are also fully backward compatible with existing IDE drives and CD-ROM drives.


Q1. What software requirements are needed to support Ultra DMA drives?

A1. 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.

Q2. How do I know if my system BIOS supports Ultra DMA IDE?

A2. 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.

Q3. Which Applications benefit from Ultra DMA?

A3. Any disk intensive applications will see the benefits of Ultra DMA's increased throughput. Applications that reside on the local Ultra DMA hard drive will load faster.

Q4. How do I ensure that the IDE host controller on my Intel 430TX PCIset or Intel 440LX AGPset based system is recognized and configured by Windows* '95?

A4. First, confirm that your system contains either the Intel 430TX PCIset or the Intel 440LX AGPset. If your computer's mainboard contains Intel devices marked 82439TX and 82371AB, then your system is based on the 430TX. If your computer's mainboard contains Intel devices marked 82439LX and 82371AB, then your system is based on the 440LX. You should contact your system manufacturer if you are unsure. If you do have a 430TX of 440LX based system, look in the Windows* '95 Device Manager. The drivers listed should appear as such:

Hard Disk Controllers

  • Intel 82371AB PCI IDE Controller
  • Primary IDE Controller (dual fifo)
  • Secondary IDE Controller (dual fifo)

Other Max. Transfer Rates :

  • IDE/ATA = 8.3 MB/s
  • EIDE/ATA-2 = 16.6 MB/s
  • Ultra SCSI = 20 MB/s
  • Ultra Wide SCSI = 40 MB/s

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