Controlling UDMA in Windows 2000

Microsoft^® Windows 2000 Knowledge Center

Taking Control of UDMA in Windows 2000

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Getting on the Right Track
While the subject of UDMA/Ultra-ATA in Windows 2000 can be confusing and appear daunting or elusive, if you take your time, do your research, and plan your steps you'll be fine.

Here's some points to remember:

Verify which controller your motherboard uses. Generally, computers manufactured two or more years ago will be UDMA or ATA/33. Computers manufactured within the last two years can be either UDMA/ATA/66 or 100.
If your system uses UDMA/ATA/66 and there are no specific controller drivers provided by the motherboard manufacturer, then using the technique outlined above, including the registry hack, may be appropriate. As an example, if you are using an Intel motherboard, you will find an abundance of information, including updated system files and an Ultra-ATA controller driver. You can read more about this here. Intel^® Ultra ATA Storage Driver and the Intel^® Chipset Software Installation Utility.
If you purchase an add-on controller card, make sure that both the card and the drivers are Windows 2000 compatible. Most important though, is to make certain that you have the most current drivers available, even if this means downloading them. Don't assume that the drivers that come with the card are the most current.
Correct placement of the drives on the IDE bus with the correct ribbon cables is critical to the proper operation of UDMA/Ultra-ATA. Ultra-ATA requires special 80 wire ribbon cables and they must be attached correctly. The master drive (drive 0) must be installed at the end of the cable and the slave drive (drive 1) must be installed on the middle connector. The connectors on 80-conductor cables are color-coded to help you attach them correctly to the drives and to the system. The blue connector attaches to the motherboard, the black attaches to device 0 (master) and the gray (middle) connector is attached to device 1 (slave).

In order for an ATA/66 system IDE bus to perform as ATA/66, all drives attached to that system bus must be ATA/66 or ATA/100 capable. In order for an ATA/100 system IDE bus to perform as ATA/100, all drives attached to that system bus must be ATA/100 capable. If you attach an ATA/33 device as a slave on an ATA/66 or ATA/100 system bus, the bus will default to ATA/33 and all devices attached to that bus will run at that speed.
Last but not least, read all of the reference articles you can find about the subject, especially those from Microsoft. We have outlined all of the most current Microsoft Knowledge Base Articles below.

Conclusion
We certainly hope we have alleviated some of your confusion. If any single conclusion can be drawn with regard to UDMA/Ultra-ATA, it should be to do your homework and don't assume that any one "How to" article is conclusive, not even ours. Technology changes almost every day! We believe, however, that we have provided you with the information you will need to safely implement Ultra-ATA on your system providing that it is supported.

If you have created a clean installation of Windows 2000 on your system, and you are unsure of whether your system is UDMA/Ultra-ATA66 or 100 capable, contact the manufacturer and seek their assistance. If you are building your own system and plan on either ATA/66 or ATA/100 performance in Windows 2000, take the time necessary to research your needs. Treat it as a puzzle and assembled the facts before purchasing the parts.

Useful References
These are the most current Microsoft Knowledge Base Articles that we are aware of that relate to ATAPI and UDMA/Ultra-ATA issues.

Q247951 - 10/21/2000 - HOWTO: Enabling UDMA66 Mode on Intel Chipsets

Q251376 - 10/21/2000 - INFO: Miniport Drivers for IDE Controllers in Windows 2000

Q271965 - 10/26/2000 - Stop 0x7b After Moving Windows 2000 System Disk to Another System

Q243018 - 10/30/2000 - Windows Hangs "Loading Machine Info" with UltraDMA ATA/66

Q254769 - 11/15/2000 - Hard Disk Is Misreported as Eight Gigabytes in Size During Setup

Q271274 - 11/15/2000 - Error Message or Unformatted Partitions After Windows 2000 SP1

Q275149 - 12/04/2000 - Err Msg "Stop 0x0000007A" During Setup on ATA66-based computer

Q168483 - 01/21/2001 - ATAPI Reports Event ID: 26 Out-of-Date Firmware Error Message

Q271644 - 02/22/2001 - Cannot Convert FAT32 to NTFS with IDE Drive Larger Than 20 GB

Q266704 - 02/22/2001 - Computer May Hang When Hot-Swapping UDMA IDE Devices

Q279757 - 02/22/2001 - ThinkPad Hangs During Startup Process with ZIP in Dock

Q260233 - 02/23/2001 - Support for ATA 100 (Mode 5 ) in Windows 2000

Q269555 - 01/12/2001 - Device Manager Lists ATA-100 Device Incorrectly as Using PIO Instead of UDMA

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